To assess the action of pentoxifylline, administered by subcutaneous route, on skin flap tissue repair in rats, and to verify the histological aspects and biomarkers.Thirty-two male Wistar rats were divided into four groups: control (CT) and treated with pentoxifylline . Modified McFarlane technique flap was used. Ten days later, the animals were euthanized and the areas of viable and necrotic tissue were evaluated. Hematoxylin/eosin staining was used to assess the morphometric characteristics of the number of vessels and epithelial thickness. Picrosirius red was used to assess collagen density. VEGF and TGF-?1 levels on the skin flap and serum of the animals were measured by the ELISA method.The macroscopic evaluation of the skin flap dimensions showed reduced necrotic tissue in the pentoxifylline (p < 0.05) treated groups. There was an increase in angiogenesis and reepithelization, demonstrated by analyses with an increased number of vessels (p < 0.05), VEGF and epithelial thickness. Fibrogenic effect showed decreased collagen density and TGF-β1 in the skin flap and serum.The benefits of pentoxifylline administered by subcutaneous route, at dose 100 mg/kg, which was effective to improve the survival of skin flap by acting on tissue repair components, stimulating angiogenesis and reepithelization, in addition to reducing fibrogenesis The skin flap surgical procedure involves complex healing and circulatory processes, which start immediately upon incision, when the integrity of the skin is broken with vessel damage and consequent activation of the coagulation cascade pathwaysThe return of the oxygen supply to the ischemic tissue generates reactive oxygen species. Products resulting from the reperfusion mechanism influence and cause inflammatory and metabolic changes mediated by free radicals, which cause structural and functional cellular changes, which may contribute to tissue necrosis35,The skin flap needs to survive and overcome all stages that lead to decreased perfusion and changes in the complex and sequential healing stages and, finally, achieve vitality throughout its extension, thus avoiding necrosisThe loss of vitality, especially in the distal segment, ranges from 9 to 65%, resulting in an impact on the patient’s quality of life, and is one of the reasons for increased health care costs, which must be avoidedIn several experimental studiesPentoxifylline is administered by oral or parenteral route for circulatory disorders and occlusive peripheral arterial diseasesThe experimental project was approved by the Animal Use Ethics Commissions  of the Universidade Federal de Minas Gerais (UFMG), Protocol No. 097/2016, and by the CEUA of the Universidade Federal de Juiz de Fora (UFJF), Protocol No. 036/2016. The ethical principles for animal experimentation were followed according to the guidelines provided by the National Council for the Control of Animal Experimentation , Brazilian Society of Laboratory Animal Science  and the Council for International Organizations of Medical Sciences (CIOMS). All protocols and procedures are in accordance with Act No. 11734, as of Oct 8 2008, and CONCEA-MCTICSurgical procedures were performed with laboratory animals at the Center for Reproduction Biology  at UFJF. The samples analyses were conducted at the Apoptosis and Angiogenesis Laboratory of the Institute of Biological Sciences at UFMG, and the other financial costs were supplemented with personal resources.ad libitum filtered water and animal feed . Each animal was kept in an individual polypropylene 49 × 34 × 16-cm cage with a stainless-steel cover, and the floor was covered with wood shavingsThe animals were kept in an air-conditioned shelf, under controlled lighting conditions (12-hour light/dark cycle), at an average temperature of 22 °C, 40–70% relative humidity, and Rattus norvegicus albinus, Rodentia, Mammalia), with an average weight of 310 g and average age of 3 months, were randomly distributed into four groups of 8 animals, namely: control group (CT) and treated groups .Thirty-two male Wistar rats . The surgical flap preparation technique was applied as proposed by Modified McFarlane et al.R, Curvelo/MG, Brazil) in the four groups. The wounds were cleaned with a 100 mL bottle of 0.9% saline solution  and gauze IV .The animals were intraperitoneally anesthetized with ketamine hydrochloride 10% at a dose of 90 mg/kg, and xylazine 2% at a dose of 10 mg/kg  underwent skin flap preparation and received a 0.9% saline solution-soaked gauze to moisten the flap bed for 30 s . The treThe animals in group P1 received 1 mL of the pentoxifylline solution by subcutaneous route in the perioperative period (D1) after the flap was prepared and before it was sutured. The animals in group P3 received 1 mL of the pentoxifylline solution on days D1, D2 and D3 in the perioperative period, 24 and 48 h after the operation, respectively. The animals in group P5 received 1 mL of the pentoxifylline solution on days D1, D2, D3, D4 and D5 in the perioperative period, 24, 48, 72 and 96 h after the operation, respectively .R, Cristália – Produtos Químicos Farmacêuticos Ltda. – Butantã-SP, Brazil). The prescription was with an administration interval of 8/8 h, for up to 3 days, as needed. In order to avoid overlapping doses, animals in groups P1, P3 and P5 received the pethidine analgesic (10 mg/kg) 30 min before pentoxifylline administration on days D1, D2, D3, D4 and D5, according to the animal groupThe animals operated on in the four groups  received the analgesic pethidine – 10mg/kgby subcutaneous route, on the left side, 3.0 cm from the flap and tail, in the perioperative period .The macroscopic aspect of the skin flap of each animal was observed, and the tissue was considered viable if it had few or no changes in the superficial layer of the rat’s skin, i.e., similar to normal tissue. The tissue was considered necrotic if the rat’s skin had a hardened texture with a dark color ranging from brown to black, as well as crustsThe animals were euthanized by increasing the ketamine dose to 180 mg/kg (90 + 180 = 270 mg/kg) and the xylazine dose to 20 mg/kg (10 + 20 = 30 mg/kg) intraperitoneally.in vivo, with a digital caliper, and the macroscopic features of the flap on the tenth day (D10) after the operation were recorded and reported to the database for statistical analysisTotal flap, necrotic tissue and viable tissue area were measured, Three animals from each group were randomly chosen to collect approximately 2 mL of blood  10% buffered formaldehyde solution vial for 48 h, labeled and sent for histological analysis. The vials containing serum and skin fragments from the proximal flap segment of the three randomly selected animals from each group were submitted for the biochemical measurement of VEGF and TGF-ß1.The sections were stained with hematoxylin-eosin (HE) and Picrosirius Red (PSR) for histological evaluation and morphometric quantification of the number of vessels, epithelial thickness, and collagen density.Tissue repair phases in the flap segments were assessed at the transition from the viable tissue to the necrotic tissue on the skin flap. The histological evaluation and morphometric analyses were performed in the central portion of all slides in the three skin flap segments. Morphometry quantification of the number of vessels and the epithelial thickness for the proximal, intermediate, and distal segments were performed. Collagen density in the four groups was obtained from the capture and binarization of the images and densitometry of all histological section fields of the skin flap fragment2) for the number of vessels, 10 fields (30.815 µm2) for epithelial thickness, and 20 fields (137.910 µm2) for collagen densityFor the morphometric analysis of the histological elements, images of sequential sections of each skin segment were obtained: 25 fields , × 20  and × 100 , respectively; they were subsequently digitized with a JVC TK-1270/JCB microcamera and transferred to an analyzer  with the screen morphometry program Image Pro-Plus 4.5 with the thickness of the epithelium.The PSR stain was used to quantify the collagen density. This stain is an anionic compound that differentiates the thickness and density of the collagen fibers based on the color that is emitted under polarized light. Light was used to view and identify the density of the collagen fibers based on the PSR staining in the center of each of the three flap segments . While the thin dissociated fibers are weakly birefringent and stained green, the denser, strongly associated fibers are intensely birefringent and emit longer-wavelength colors, such as red and yellow. The slides were analyzed with a ×10 objective. Images were obtained out of every 20 fields/slides in areas with a higher concentration of collagen fibers. Pixel densities for the regions occupied by the collagen fibers were selected on the real image for subsequent creation of a binary image for densitometric quantificationThe biochemical measurements of VEGF levels were used to quantify angiogenesis stimulation. The TGF-ß1 level was used to quantify the stimulation to collagen depositionEighty microliters of the remaining supernatant from the flap skin fragment sample were used to find VEGF and TGF-ß1 in the skin flaps and serum of the animals. Eighty microliters of the animal serum were used to measure the systemic levels. The VEGF and TGF-1 levels were measured in the skin flap sample (mean weight of 20 g) and in the blood serum of three animals (n = 3) from each group.The enzyme assay followed the steps in the standardized protocol provided by the Kit Duoset (R&D Systems) supplier. Dilutions of cell-free supernatants were added in duplicate to the enzyme-linked immunoabsorbent assay (ELISA) plate, which had a rat-specific monoclonal antibody against the cytokine, followed by the addition of a second detection antibody. After washing to remove unbound antibodies, a substrate solution was added to the ELISA plate (50 µL of 1: 1 hydrogen peroxide solution and 10 mg/mL OPD). The reaction was stopped after 20 min of incubation with 2 N sulfuric acid (50 µL), and the color intensity was quantified at 540 nm in a microplate reader (Thermoplate). The standards were dilutions of recombinant rat cytokines from 7.5 pg to 1.000 pg/mL (100 µL). The results were expressed as cytokine picograms per milligrams of wet weight or milliliter of serumThe sample calculation was based on enough investigated animals to achieve statistical representativeness for the analysis of the variables: total flap size, necrotic tissue size, viable tissue size, number of vessels, reepithelialization, and collagen densityAll data were expressed as mean ± standard error of the mean (SEM). The assumptions of normality and homoscedasticity were determined by Kolmogorov–Smirnov tests for subsequent statistical analysis.The level of significance was considered of 0.05, with a variation coefficient of 15 to 20% for the differences between the group CT and the pentoxifylline-treated groups P1, P3 and P5. The weight variable was evaluated to verify the animals’ health, as measured on the day of the operation (D1) and on the day of euthanasia (D10). The Newman–Keuls post-test was used to compare and detect significant differences between the averages in the four groups and variables with a parametric distribution, which are the measures of total flap size, viable tissue, necrotic tissue, collagen density, VEGF and TGF-ß1. The Kruskal–Wallis test and the Dunn’s post-test were used for nonparametric distribution data to compare and detect significant differences between the averages in the four groups.The quantified tissue-repair variables were the number of vessels, epithelial thickness, and collagen density with eight animals per group. For the VEGF and TGF-ß1 measurements, there were three animals per group. The results were analyzed using the GraphPad Prism 5.0 software, and graphs were created based on the data in the tables.All animals remained healthy during the experiment.Total flap area measured after 10 days of experiment were significantly reduced between CT and P5, p < 0.05. Significant differences were observed in the necrotic tissue area of CT compared with P3 and P5, showing that the necrotic tissue was reduced in treated groups P3 and P5 . Viable When comparing the groups CT and P5, there was a significant difference in the proximal, intermediate, and distal segments of the skin flap, p < 0.05 . The phoEpithelial thickness increased in the three skin flap segments of the treated groups when compared with the control group. A revieWhen comparing groups there was a decrease in collagen density in the three segments of the skin flap in the pentoxifylline-treated groups . A higheVascular endothelial growth factor levels were higher in the skin compared with the serum of the animals, but it levels was increased in group P5 compared with P1 with a significant difference, p < 0.05 . The TGFThe animals were observed throughout the 10 days of the experiment to evaluate tissue repair, as the complete formation of the secondary vascular pedicle occurs around the 9th dayPentoxifylline has a classical therapeutic indication for the treatment of circulatory disorders and occlusive peripheral arterial diseases, studies have administration included a protective effect against flap necrosis, when administered orally and parenterally. Even though, administration of pentoxifylline by subcutaneous route has minimal systemic repercussions, over the oral route, and it does not require repeated doses to reach the desired serum levelImportantly, a significant improvement in tissue repair was observed in previous research, when 20 mg/kg of pentoxifylline and 5% dimethyl sulfoxide were administered by subcutaneous route in the perioperative period in the flap skin modelThe safety of the pentoxifylline dose was based on the median lethal dose (LD50), which is 195 mg/kg after intraperitoneal administration and 1.385 mg/kg after oral administration in mice. The LD50 of the drug in rats is 230 mg/kg after intraperitoneal administration and 1.770 mg/kg body weight after oral administrationIn the present study, the macroscopic analysis of the skin flap vitality showed an increase in the viable tissue area with a consequently decrease in the necrosis area in the pentoxifylline-treated groups. It is important to note that granulation tissue was composed of an exuberant vascular component in the dermis and hypodermis under the necrotic area, thus characterizing necrosis of the epidermis only. The presence of granulation tissue in the layers underlying the necrotic tissue may be an important factor for secondary surgical procedures when necessary in medical practice.OtherIn this research, the histological evaluation of the skin flaps showed an increase in the number of vessels in the proximal, intermediate and distal segments of groups P3 and P5 compared with P1, i.e., in the groups with a long administration period of pentoxifylline during the postoperative period. Moreover, an increase in angiogenesis occurred in the three skin flap segments, and the effects of pentoxifylline were observed already with three days of pentoxifylline administration, including in the distal segment of the flap, which is the one furthest away from the vascular pedicle. An increase in the number of vessels was also observed under the flap necrotic area compared with group CT.The proangiogenic effects of pentoxifylline on ischemic tissues have been observed in several studies. The administration of intradermal hyaluronidase combined with intraperitoneal pentoxifylline for 14 days showed a decrease in the cellularity of macrophages on the dermis, while the administration of pentoxifylline alone stimulated angiogenesisConsidering skin flap reepithelialization in this study, the pentoxifylline-treated groups of animals had an increase in epithelial thickness in the three segments of the skin flap analyzed, and in the proximal segment there was an increase after the third day of drug administration. The morphometric analyses of epithelial thickness in the four study groups showed an influence and action of pentoxifylline, such as in the migration of keratinocytes that stimulated reepithelization, to complete the repair of the flaps, as the drug was administered for a long period of time. The flap necrosis area also showed increased epithelial thickness with granulation tissue formation in the dermis to the hypodermis.In this study, the morphometric analysis showed a decrease in collagen density and greater organization of the connective tissue in the proximal, intermediate, and distal segments of the skin flaps, especially when pentoxifylline was administered for a long period of time. Evidence of these alterations was found after the third day of administration on all flap segments, and from the first day on in the distal segment. The flap necrosis area also showed decreased collagen density in the granulation tissue from dermis to hypodermis, suggesting pentoxifylline had an antifibrogenic action.in vitro researchDespite different methodologies, the literature has published researchesMeasurements of growth factors VEGF and TGF-ß1 were performed in the proximal segment of the flap in three animals only in each group, since the scope of the research was to verify the action of pentoxifylline on the elements of tissue repair. The results of these measurements were aligned with the investigation on the actions of pentoxifylline on the skin flap tissue repair in rats.The VEGF levels were higher in the skin flap than in the serum of the animals, and both showed a significant increase in this protein in the treated groups. This result suggests that pentoxifylline stimulated the production/liberation of this important angiogenic molecule and corroborate with the results in the literatureThe measurement of TGF-ß1 levels showed a significant decrease in the level of this growth factor in the skin and in the serum of pentoxifylline-treated animals. This fact suggests that the drug acted by reducing the release of TGF-ß1at the local and systemic level and is more pronounced in the groups of animals receiving pentoxifylline, administered by subcutaneous route, for more days, suggesting an antifibrogenic role for the drug. The granulation tissue in groups P3 and P5 had exuberant vascularization and greater organization of the collagen fibers, when compared with groups CT and P1. Other studiesThe morphometry of epithelial thickness, number of vessels, collagen density, VEGF and TGF-ß1 levels, as well as the morphological analyses of the flap segments showed that pentoxifylline acts on the angiogenesis, with benefits in the survival and tissue repair of the flaps and, consequently, decreased necrosis.These findings may help to enhance flap survival with the pharmacological strategy of an available drug administered by subcutaneous route, in addition to benefits such as affordable cost, easy administration, high therapeutic index, effective results, treatment feasibility, known mechanism of action when administered via oral and parenteral routes, bioavailability and protective effects on necrosis. Pentoxifylline suggests that it is dose-dependent, with a possible variability in the different effects based on the dose, schedule, route, and administration periodHowever, these results showed that the proposed scheme at a subcutaneous dose of 100 mg/kg/day, administered by subcutaneous route, was effective in increasing flap vitality and survival. Angiogenesis was stimulated, with increased number of vessels, increased VEGF, increased epithelial thickness – phases that integrate tissue repair, with a consequent decrease in tissue necrosis. It showed an antifibrogenic effect with decreased collagen density and decreased skin flap TGF-ß1 in rats. The relevance of the benefits provided by pentoxifylline, administered by subcutaneous route, in skin flaps of rats allows the inference of its effectiveness in the survival, protective effect on necrosis, angiogenesis stimulation, and decreased fibrogenesis.There are certainly several other ways to investigate in order to elucidate and expand the knowledge on pentoxifylline and its applicability. The exact mechanisms of action when it is administered by subcutaneous route require further research to clarify the dose. The contribution of this research was to corroborate that pentoxifylline at a dose of 100 mg/kg, when administered by subcutaneous route, is an adequate option for another route of administration of the drug, which so far had been used via parenteral and oral routes.The purpose of this study was to evaluate the action of subcutaneous pentoxifylline on tissue repair and the benefits of the drug, such as increasing tissue survival and decreasing skin flap necrosis in rats – which is a proven fact. However, even in the presence of necrosis in the epidermis, granulation tissue was formed in the layers of the deep dermis and hypodermis. This fact is important for the successful skin coverage in subsequent procedures, as it will decrease hospitalization time, patient distress, and the financial costs in future, if. In view of the antifibrogenic effect of pentoxifylline, studies with the drug at a dose of 100 mg/kg by subcutaneous route with a diversified scheme may also be proposed.Pentoxifylline administered by subcutaneous route, at dose of 100 mg/kg, increased survival and tissue repair in rats treated for a three and five days. The benefits of pentoxifylline, were characterized by an evident increase in angiogenesis shown by increase in the number of vessels, corroborated by higher levels of VEGF in skin and serum, increased epithelial thickness with increased reepithelization in the skin flap. There was also an antifibrogenic effect with decreased collagen density, corroborated by diminished of TGF-ß1 levels in the skin and animal’s serum.


In this study, the carrier effect of zeolite sands in reducing the autogenous shrinkage and optimizing the microstructure of ultra-high-performance concrete (UHPC) is studied. Pre-wetted calcined zeolite sand (CZ), calcined at 500 °C for 30 min, and natural zeolite sand (NZ), with 15 wt.% and 30 wt.% in UHPC, are used to partially replace standard sands. On that basis, a series of experiments are executed on the developed UHPC, including compressive strength, autogenous shrinkage, X-ray diffraction (XRD), and isothermal calorimetry experiments. With the increase of the zeolite sand content, the autogenous shrinkage of UHPC decreases gradually. Moreover, when the added CZ content is 30 wt.% (CZ30 specimen), it is effective in reducing autogenous shrinkage. Meanwhile, at the age of 28 days, the compressive strength of CZ30 is 97% of the control group. In summary, it is possible to effectively reduce the autogenous shrinkage of UHPC containing 30 wt.% CZ, without sacrificing its mechanical properties. In recent years, due to the increasing demand for concrete, ordinary and high-performance concrete (HPC) may not meet actual engineering needs. Thus, ultra-high-performance concrete (UHPC) is of increasing interest to researchers. Compared with ordinary concrete, UHPC shows a more dense microstructure and excellent compressive strength, because it contains a large amount of cement-based materials, has a low water/binder (w/b) ratio, and uses a large number of superplasticizers ,2. In adResearchers have studied the following five methods to reduce the occurrence of the autogenous shrinkage of UHPC: (1) the control of the hydration reaction; (2) reduction of the internal restraint; (3) reduction of the surface tension of the pore solution; (4) formation of expansive products; and (5) replenishment of water through internal curing. Of these five methods, internal curing is considered to be the most effective and straightforward method . SuperabIn practical engineering applications, most construction workers are highly interested in maintaining a similar compressive strength while reducing the autogenous shrinkage of concrete. The aim of this paper is to use pre-wetted zeolite sand to replace a portion of the standard sand in UHPC in order to significantly reduce the autogenous shrinkage of UHPC, without a significant loss of strength caused by adding the zeolite sand. The research methods implemented include water absorption, autogenous shrinkage, compressive strength, X-ray diffraction, and isothermal calorimetry tests.The innovations of this paper are summarized as follows: Firstly, we find the use of 30 wt.% calcined zeolite sand can reduce the autogenous shrinkage of UHPC without reducing its compressive strength. Secondly, we find zeolite sand is not chemically inert, and the dissolution of fine zeolite sand particles changes the alkali ion concentration of the solution, accelerates the early binder hydration, and promotes the setting of the binder. Finally, the calcination can increase the water-absorbing capacity of zeolite sand and the internal curing effect of zeolite sand is enhanced after calcination.In this paper, zeolite sands with minimum and maximum particle sizes of 1 mm and 3 mm, respectively, were used as internal curing agents of UHPC. To observe the influence of calcined zeolite sand on UHPC, natural zeolite sand particles were heated for 30 min in a muffle furnace at 500 °C. The chemical compositions of cement, silica fume, and zeolite sand, measured by X-ray fluorescence (XRF), are shown in The XRF fused cast bead method (ISO 12677:2003) was used in the sample preparation . Samples of lithium tetraborate and lithium metaborate (each ~4 g) and a test sample (~0.8 g) were mixed for preparing the beads. The resistance furnace was heated to a fixed temperature of 1025 ± 25 °C .The SEM images of the natural zeolite sand and calcined zeolite sand are shown in Microscopic observation of the sheet samples was performed using a high-resolution field emission scanning electron microscope  with an acceleration voltage of 1.5 kV and an emission current of 7000 nA. The zeolite sands were broken, and the inner sheet was selected for testing. Prior to microscopic observation, the surface of the samples was coated with platinum for 30 min using a Hitachi E-1010 ion sputterer  . As showTo achieve the objectives of this study, two sets of tests were conducted. In the first test group, the natural zeolite sand was used as the internal curing agent, and the additional amounts were 15 wt.% and 30 wt.% of standard sand, respectively. The UHPC specimens are marked as NZ15 and NZ30. In the second test group, calcined zeolite sand was used as an internal curing agent, and the additional amounts ware 15 wt.% and 30 wt.% of standard sand, respectively. The UHPC specimens are marked as CZ15 and CZ30. The water absorbed by the zeolite sands, before setting, has no effect on the porosity of the concrete and is therefore not considered to be part of the ‘water/cement ratio’ of a particular concrete mixture . The mixThis paper focuses on the internal curing effect of zeolite sand on strength and autogenous shrinkage. Since steel fiber is mainly used to improve the ductility of UHPC, and ductility is not the aim of this paper, we did not use fiber.The natural zeolite sand and calcined zeolite sand, soaked in water for 48 h, were taken out. The soaked zeolite sands were unfolded with a paper towel, and a paper towel was placed on the surface of the zeolite sands to dry the surface of the zeolite sands . The aboSince the absorption of water by the zeolite sand specimens occurs over time, to determine the absorption of water changing with time, the volumetric flask test was used to determine the saturation of the zeolite sand specimens for 24 h. The specimens were placed in an oven at 105 °C for 24 h and cooled for another 24 h. The measuring method of water absorption was the same as that used in . Of the A corrugated tube method, based on ASTM C1698–09 , was useThe compressive strength of the designed UHPC was tested , based on the ASTM C39 . The cemX-ray powder diffraction (XRD) analysis was conducted on the raw materials  and the samples (after 28 days of curing) after the hydration stoppage treatment. The solvent exchange method was used for hydration stoppage of the hydrated samples . We grouIn previous studies, most of the specimens for isothermal calorimetry were pastes, without a fine aggregate. These studies ignored the effect of fine aggregates on the heat of hydration. Conversely, in this study, to clarify the effect of fine zeolite aggregates on the heat of hydration, a mortar specimen with a fine zeolite aggregate was used for isothermal calorimetry. The heat release rate and accumulated hydration heat of the adhesives were measured using a TAM-Air  for 72 h at 20 °C. Due to the low water binders (w/b = 0.2), all mortars were mixed by a mortar mixer and transferred to glass bottles .The water absorption of the natural zeolite sand reached 7.78% in the first 6 h, while the calcined zeolite sand reached 22.67%. The total water absorption increased with time, and the final water absorption of the natural zeolite sand reached 8.08%, while the calcined zeolite sand reached 23.43%. The water absorption of the calcined zeolite sand was higher than that of the natural zeolite sand. This is due to the initial physical bonding water present in the natural zeolite sand being evaporated during heating, resulting in more pores becoming empty. Similar results were obtained in . The expAll the mortars are placed in a corrugated tube, and the autogenous shrinkage of the mortars, during the 7-day period, was measured using the deformation measurement setup. The test data are shown in The control group is labeled as Z0, and the test pieces with the calcined zeolite sand, containing 15 wt.% and 30 wt.%, are labeled as CZ15 and CZ30, respectively. The test pieces with natural zeolite sand, containing 15 wt.% and 30 wt.%, are labeled as NZ15 and NZ30, respectively. It is observed in First, the shrinkage of Z0 increases rapidly within the first 12 h and slowly increases after 12 h. However, specimens containing calcined or natural zeolite sand remain unchanged after the inflection point. This is because the addition of zeolite sand is equivalent to adding a reservoir to the cement and, with the binder hydration, the internal curing water of zeolite sand is released and continues to participate in the hydration reaction, thus slowing down the occurrence of autogenous shrinkage. Similar results have been confirmed in previous studies ,41.Second, calcined zeolite sand is more effective in reducing the autogenous shrinkage of the specimens. The shrinkage of the specimens containing calcined zeolite sand  is lower than that of specimens containing natural zeolite sand . This means that the modification of zeolites is more helpful in improving the storage capacity of pores. While the specimens contain the same amount of zeolite sand, the calcined zeolite sand absorbed more internal curing water than the natural zeolite sand. The specimens containing the calcined zeolite sand released more internal curing water, and the released internal curing water increased the relative humidity inside the UHPC. Consequently, the shrinkage of the specimens with calcined zeolite sand is smaller than that of the specimens with natural zeolite sand.XRD measurements were conducted on both the natural zeolite sand and calcined zeolite sand, and the experimental results are shown in 2O3·7SiO2·5H2O), synthesized by CaO·Al2O3·7SiO2 in the temperature range of 250–360 °C. The calcined zeolite sand belongs to the epistilbite series (CaO·Al2O3·5.5SiO2·5H2O), synthesized by the CaO·Al2O3·5.5SiO2 composite [Calcined zeolite sand belongs to the heulandite series, which includes a kind of thermally stable heulandite zeolite 2 peaks in CZ15/30 and those in NZ15/30 are not obvious. XRD qualitative analysis method can determine the type and relative quantity of hydration productions, but it cannot determine the specific amount of hydration products. Therefore, the XRD qualitative analysis is not the best method of analyzing the degree of hydration. TGA can be used as a quantitative analysis method to measure the content of chemically bound water and calcium hydroxide. Compared with XRD qualitative analysis, TGA is a much better way to determine the degree of hydration, and a TGA experimental study will be conducted in the future.This is because the specimens containing zeolite sands contain more internal curing water . With thAll mortars were mixed by a mortar mixer and transferred to a TAM-Air. The heat release rate and accumulated hydration heat of the adhesives were measured using a TAM-Air for 72 h at 20 °C. According to the hydration heat release curve of mortars, the cement hydration could be divided into five periods: (1) initial (pre-induction) period; (2) induction period; (3) acceleration (post-induction) period; (4) deceleration period; and (5) diffusion period . BecauseAs shown in For the UHPC containing calcined zeolite sand, as the content of calcined zeolite sand increased, the heat release rate of mortars accelerated. The heat release rate of mortars containing 30 wt.% of zeolite sand was the highest in the same group, which may be due to the addition of a large amount of zeolite sand, since soluble zeolite sand particles increase the content of alkali ions . The samIn the acceleration period, the time at which heat flow peaks of each hydration heat level appear are in the order of NZ30 > CZ30 > NZ15 > CZ15 > Z0. This is because some small zeolite sand particles are dissolved, and the alkali ion concentration is increased, which accelerates the binder hydration, causing the setting time to increase. During the deceleration period, it could be observed that the slope of the heat release rate curve of CZ15 was the same as that of CZ30 with respect to the hydration reaction. The slope of the heat release rate curve of NZ15 was the same as that of NZ30 with respect to the hydration reaction. Finally, in the diffusion period, the heat release rates of the mortars containing calcined zeolite sand and natural zeolite sand were higher than those of the control group, Z0.The compressive strength, measured by cube specimens with dimensions of 50 mm × 50 mm × 50 mm, of UHPC at 3, 7, and 28 days, is shown in At an age of 3 days, compared with the Z0, with the addition of zeolite sand, the compressive strength decreased. This is because zeolite sand is a porous material, and the addition of zeolite sand increases the porosity of concrete. Moreover, with the content of natural zeolite sand increasing from 15 wt.% to 30 wt.%, the compressive strength decreased because of the negative effect of porous zeolite sands. The compressive strengths of the NZ15 and NZ30 specimens are similar to those of CZ15 and CZ30 at early ages.However, up to the age of 28 days, the compressive strengths of NZ15 (87.13 MPa) and NZ30 (83.56 MPa) are smaller (15.51% and 18.97%) than those of Z0 (103.12 MPa). The negative effect seems to have been compensated for. The compressive strength of CZ30 increases significantly, achieving 99.29 MPa, which is close to the compressive strength of Z0—about 103.12 MPa. The compressive strengths of CZ15 and CZ30 are 6% and 3.7%, which are lower than that of Z0. This may be due to the release of internal curing water in the zeolite sands, which fills the pores in the zeolite sands and improves the compressive strength of UHPC .From 3 to 28 days, the incremental degree of strength for Z0 and CZ30 is different due to the effect of internal curing. The incremental degree of strength equals the ratio of the strength at 28 days to the strength at 3 days, and, regarding the increment degree of strength, Z0 increased by 1.64 (103.12/62.93 MPa) and CZ30 increased by 2.06 (99.29/48.18 MPa). The compressive strength of CZ30 increased more obviously. This is mainly because the addition of zeolite sand increased the porosity of the specimens. However, as the hydration reaction proceeds, the release of the internal curing water of the reservoir promotes the hydration of the cement, which significantly increases the compressive strength of the specimen at a later age. Therefore, the use of calcined zeolite sand as an autogenous curing agent has no obvious impairing effect on the compressive strength of UHPC.UHPC can be divided into two types, namely, precast UPHC and cast-in-place UHPC. For cast-in-place UHPC, autogenous shrinkage is an essential constraint because UHPC has a very low water-to-binder ratio. Construction companies are urgently seeking a solution to mitigate or minimize autogenous shrinkage without impairing the strength. In this study, we find the calcined zeolite sand is an effective internal curing material for UHPC. Compared with the control specimen, the autogenous shrinkage of concrete with 30% calcined zeolite sand is significantly lower while the 28-day compressive strength is similar.On the other hand, the compressive strength of the UHPC designed in this paper did not reach 150 MPa . This may due to many factors affecting the strength of UHPC, such as: fibers , binder Compared with natural zeolite sand, the water absorption of calcined zeolite sand is obviously increased. This is due to the initial physical bonding water present in the natural zeolite sand being evaporated during heating, resulting in more pores becoming empty.The autogenous shrinkage of self-curing UHPC is significantly reduced due to the addition of zeolite sands. Among the resulting outcomes, the effect of adding calcined zeolite sand to UHPC is the most obvious. This is because calcined zeolite sand can absorb more internal curing water before mixing. With the occurrence of the hydration reaction, internal curing water is released to continue to participate in the hydration reaction, thereby reducing autogenous shrinkage.For specimens with zeolite sand additions, XRD analysis showed that there were no new hydration-product peaks, indicating that zeolite sand particles do not participate in binder hydration. The peak of calcium hydroxide increased significantly with the addition of the zeolite sands. This is because the specimens containing zeolite sands contain more internal curing water. With the occurrence of the cement hydration reaction, the water in the reservoir is released to further promote cement hydration, and more hydration products are obtained.It could be observed that the total heat released from self-curing UHPC is higher than that from the control group, Z0. In the initial period, the heat release rate of self-curing UHPC increased because of the addition of zeolite sand. As the content of calcined zeolite sand increased, the heat release rate of the mortars accelerated. In the acceleration period, the time at which heat flow peaks of each hydration heat level appeared is in the order of NZ30 > CZ30 > NZ15 > CZ15 > Z0. During the deceleration period, it could be observed that the slope of the heat release rate cures of CZ15 is the same as that of CZ30 with respect to the hydration reaction. The slope of the heat release rate cures of NZ15 is the same as that of NZ30 with respect to the hydration reaction.At the age of 3 days, UHPC has a negative effect due to the addition of zeolite sands with pores, which reduces the compressive strength. However, at the age of 28 days, UHPC with calcined zeolite sand showed a good compressive strength, compared with the control group. This is due to the fact that calcined zeolite sand absorbs more internal curing water, and the internal curing water is released to participate in binder hydration and contributes to the development of compressive strength.Studying the effects of natural zeolite sand and calcined zeolite sand on the properties of UHPC, the following conclusions can be drawn from the present study:In summary, adding 30 wt.% of calcined zeolite sand as an internal curing agent has a positive effect in reducing the autogenic shrinkage strain of UHPC, without sacrificing compressive strength.


Zone of inhibition studies of TiO2-infused cementitious samples showed efficacy toward both Gram-negative and Gram-positive bacteria.The formation of biofilms on cementitious building surfaces can cause visible discoloration and premature deterioration, and it can also represent a potential health threat to building occupants. The use of embedded biofilm-resistant photoactivated TiO At the fectants ,9,10,11.2 were discovered in the 1950s, but their exploitation in practical applications began only in 1972, when Fujishima and Honda used it for water splitting. Another very important property of TiO2 is its photoinduced superhydrophilicity, which was unexpectedly discovered in 1995 in SiO2/TiO2 composites illuminated by ultraviolet (UV) light.The specific properties of TiO2-SiO2 compounds is that, unlike TiO2, whose photocatalytic activity ceases without UV illumination, their photocatalytic effect continues for hours or even days after the removal of the UV source. In 1997, the first publication by Luigi Cassar et al. focused on the production of cementitious materials with self-cleaning properties [2 nanoparticles on the performance of cement composites: reduction of intake time, increase of the degree of cement hydration, increase of mechanical resistances , adhesion to the reinforcement and resistance to its corrosion, and improvement of durability and freeze–thaw resistance [An important feature of TiOoperties . A signisistance ,14,15,16Saccharomyces cerevisiae (yeast), Lactobacillus acidophilus and Escherichia coli (bacteria), and Chlorella vulgaris  in water [2 (which occurs for UV radiation), photogenerated electrons (e−) and holes (h+) react with O2 and H2O, forming anionic radicals (O2−) and (OH). These oxidative species  are highly reactive, contributing to the destruction of the cells of microorganisms [In 1985, Matsunaga et al. first demonstrated the photocatalytic cytotoxic mechanisms in microbial cells from in water ,19,20,21rganisms ,24,25,26Escherichia coli bacteria. Saito et al. [2. Oguma et al. [2. Evidences highlight that wavelengths in the range of 320–400 nm are the most efficient to activate the photo-cytotoxic activity of TiO2. Gogniat et al. [2 is positively correlated with its biocidal effect. Adsorption has been consistently associated with a reduction in the integrity of the bacterial membrane, as indicated by flow cytometry. The authors suggested that the adsorption of cells on photoactivated TiO2 is followed by a loss of membrane integrity, which was key to the biocidal effect. Mazurkova et al. [2 on the influenza virus, indicating the destruction of the virus in the presence of nanoparticles. After 15 min of incubation, the nanoparticles adhered to the outer surface of the virus, the surface spinules of the virus were glued together, and its outer membrane, of a lipoprotein nature, was torn. After 30 min, the degree of destruction increased, and after 1–5 h of incubation, the virus that came into contact with the nanoparticles was completely destroyed. It is considered that this effect depends on the duration of exposure/incubation, the viral concentration, and the concentration of nano-TiO2. The tests were carried out in three lighting conditions: dark, UV radiation, and natural light. Adams et al. [Bacillus subtilis and Escherichia coli were reduced upon contact with a suspension of nano-TiO2 under natural light illumination. A similar effect on Bacillus subtilis has been reported by Armelao et al. [2 indicated their biocidal effect in the presence of Escherichia coli, Enterococcus faecalis, and Pseudomonas Aeruginosa, after 2 days of exposure to artificial light. Results were also consistent with those of Gurr [2 composites is manifested in the presence of natural light, without necessarily requiring UV photoactivation. The study carried out by Hamdani [2-based type-Aeroxide P25, when in contact with E. coli, they were able to reduce the viability of bacteria after 24 h of exposure by 60–70%. The main observation, based on results in the literature [2 have the ability to inhibit biofilm growth, destroying the E-coli bacteria with which they come in contact. This is also supported by results obtained by Daly et al. [2 (OH● and O2−), at the cellular level, plasma components such as DNA, RNA, lipids, and proteins are destroyed, and cell membranes are broken.A number of studies have been carried out in this direction. Sunada et al.  have shoo et al.  proposeda et al.  discusset et al.  showed ta et al.  analyzedo et al. . Researco et al.  on sampl of Gurr , who ass Hamdani  has showterature ,38,39, iy et al. , and Kuby et al. , which cThe easiest method of studying the resistance capacity of various building materials to the attack of microorganisms is the adapted antibiogram method, which is already used in medicine. This method is known as the halo inhibition method  or the K2, there is still controversy about maintaining the bactericidal capacity in the absence of light (during the night), as well as the influence of the type of bacteria that contaminate the surface. Results show that their destruction begins after only 20 min of UV radiation exposure and 60–120 min is sufficient to destroy all the bacteria [Escherichia coli bacteria which is 103–104 times more effective than chemical disinfection products [Although a large number of authors confirm the anti-bactericidal capacity of cement compounds with nano-TiObacteria , since hproducts .2, using the zone of inhibition to get a quick test of the antibacterial efficiency, and to identify the nanoparticle-functionalized regions in relation to the amount of cement, which ensure a successful effect of resistance from a biological point of view. For this purpose, four types of bacteria were used, which were chosen because of the frequency with which they are encountered in the building environment: Escherichia coli, Pseudomonas Aeruginosa, Staphylococcus Aureus, and Streptococcus Pyogenes.The aim of this work is to analyze the potential of inhibiting the growth of bacterial films on the surface of cementitious composites by adding different amounts of nano-TiO2, concrete covered by a thick layer of photoactive concrete on the top, and finally, different weight percentages of TiO2 in the concrete mass (when TiO2 substitutes cement or is present as additive) [2 nanoparticles into the cementitious mass) and even economic impact in terms of costs [In order to study the self-cleaning and anti-bacterial properties of cementitious composites, the literature shows three types of concrete modifications: concrete covered with a thin layer of TiOdditive) . Each ofof costs . The metof costs .2 nanoparticles as addition in different mass percentages, relative to cement quantity. Preliminary results obtained on the same mix-design ratios, when subjected to the method of staining with Rhodamine B and methylene blue, extended even for the situation of staining with exhaustion gas particles on the surface of the samples [2 addition in the cementitious matrix and thus the self-cleaning capacity of the samples. Furthermore, the influence of added TiO2 nanoparticles on the hydrophilicity of the cementitious composites surfaces was studied on the same mixtures [The preparation of the cementitious composites was performed by using white Portland cement as binder and by adding TiO samples ,49, havemixtures .2 nanoparticles, 99.5% purity , containing more than 70% anatase, with a minor amount of rutile and a small amount of amorphous phase anatase and rutile crystallites, with a reported ratio of 70:30 or 80:20, were used in the production of the samples. Both phases play an important role in industrial applications and contribute to the photoactivation mechanism [2 particles is 21 nm, with a specific surface of 35–65 m2/g. The test specimens were prepared and conditioned as shown in Commercial Aeroxide P25 TiOThen, the cementitious composite paste was cast into rectangular molds from which small, 17.4 mm circular samples were cut. Then, the samples were subjected to photoactivation, undergoing a 24 h UV ray treatment by using a light source with 400–315 nm spectrum emission (corresponding to the UVA band), which was located at a distance of 10 cm above the surface of the specimens, which determined a luminous flux intensity of 860 lux.2 cementitious composite samples, Escherichia coli (ATCC 25922), Pseudomonas Aeruginosa (ATCC 27853), Staphylococcus Aureus (ATCC 25923), and Streptococcus Pyogenes (ATCC 19615) solutions have been used. These solutions were prepared by harvesting them from reference bacteria cultures and introducing 2 colonies (2 loops of 1 µL each) of biological material into 1 mL of physiological serum. The biological load of the prepared solutions was semi-quantified by the contact plate method, using the specifications of MicroKount® microbilogic load test . This was considered the primary control sample and was used to demonstrate the viability of the used bacteria in the suspensions.Romanian STAS 12718 offers the possibility of semi-quantitative quantification of the microbiological load of the system, providing a quantification grid as follows: 0 (−) no growth (sterile); 1 (+) 1–10 colonies of microorganisms; 2 (++) over 10 colonies of microorganisms; 3 (+++) areas with confluent colonies; 4 (++++) growth throughout the surface.Then, the farming systems were placed in the laboratory, at a temperature of 30 °C, under natural light conditions. As a result of exposure to natural light, the photoactivation process initially induced by UV exposure was continuously refreshed throughout 21 days, similarly to the alternation of day/night periods. Moreover, the initial UV exposure, for 24 h, ensured the sterilization of the cementitious samples so that there was no pre-existing contamination. At regular intervals of time, i.e., 2, 3, 4, 6, 7, 14, and 21 days, the development of the systems was examined visually and microscopically for signs of growth/development of the material (the colonies). The presence/development of the halo of inhibition was also studied. The quantification of the behavior of the bacteria contaminated samples was carried out qualitatively, according to STAS 12718  and usin2 photoactivation was assessed quantitatively by introducing a quantifiable parameter, EEA, which represents the percentage change in the diameter of the inhibition halo of the analyzed sample , according to Equation (7).%TiO2—inhibition halo diameter measured for the sample with TiO2% > 0 (mm); φcontrol—inhibition halo diameter measured for TiO2 0% control sample (mm).The effectiveness of the antibacterial effect induced by nano-TiO2 in an environment contaminated with Escherichia coli are presented in Pseudomonas Aeruginosa, results are presented in Staphylococcus Aureus, results are shown in Streptococcus Pyogenes, results are shown in Experimental results on the behavior of cementitious composites with the addition of TiONo traces of contamination/development of bacterial colonies were observed on the surface of any of the tested cementitious material samples during the entire test period (21 days).Pseudomonas Aeruginosa, for which no inhibition halo was identified in the cementitious composite control system.In the first 48 h after exposure in the contaminated environment, the formation of inhibition haloes was observed, which remained constant in size and shape throughout the test. The systems presented a concentric shape: the cementitious composite sample being surrounded by a circular area with microbiological load, evaluated according to STAS 12718/1989, in Class 0 (-). This was followed by a zone of growth and the development of biological material. This increase was more intense as the distance from the edge of the cementitious composite increased . The onl2) had in general a smaller halo diameter than samples with lower nanoparticle content. This behavior can be attributed to the inhomogeneity and the improper dispersion of nanoparticles in the cementitious matrix, which may tend to agglomerate.Sample P10  also indicated resistance to the development of bacteria. This mainly happened because of the chemical composition of white Portland cement, which usually contains a certain quantity of TiO2.The formation of the inhibition halo for the control composite system  of more than 10% (2 addition.Cementitious composites with nano-TiOthan 10% . The hig2—(Class 0 (-))—maintain this sterile behavior longer (even after 7 days of exposure in contaminated environment—sample P6 (4% TiO2)). In addition, the P3 sample (2% TiO2) had a distinguished behavior, by keeping Class 1 (+) constant until the end of the test period.When evaluating the entire system by quantifying the microbiological load of the system, according to STAS 12718 , ClassesIn the case of the P0 system, the formation of zones with confluent colonies (Class 3 (+++)) was observed earlier, after only 4 days at exposure in the contaminated environment. This confirmed the viability of the inoculated bacterial material.In case of contamination with Pseudomonas Aeruginosa, the following aspects can be identified:2, large inhibition halos have been observed.Due to the lack of visible and measurable inhibition halo in the control sample, the effectiveness of the antibacterial effect (EEA) could not be calculated, thus indicating a resistance effect to these bacteria of the cementitious composite matrix . However2, the framing Class 2 (++) was maintained throughout the 21 days of testing. This also happened for sample P4 (3% TiO2), whose framing class changed from 2 (++) to 3 (+++) only at the last stage of testing (during 14–21 days of exposure in the contaminated environment).When evaluating the entire system by quantifying the microbiological load of the system, according to STAS 12718 , Class 22), the formation of areas with Class 3 (+++) confluent colonies was rapidly observed after 2 days of exposure in the contaminated environment, which on the one hand indicates the pre-viability of the bacterial inoculum material and on the other hand indicates the lack of antibacterial activity in the case of the P1 control composite matrix (0% TiO2) (In the case of the P0 system and the P1 control sample system (0% TiO0% TiO2) .In the case of contamination with Staphylococcus Aureus, the following aspects could be identified:2 in the range of 1% to 5% had the most satisfactory behavior, i.e., an efficiency of the antibacterial effect (EEA) of more than 25%  was observed after 3 days of exposure, which confirms the viability of the inoculated bacterial material .In the case of contamination with Streptococcus Pyogenes, the following aspects could be identified:2 content in the range of 3–6% showed better behavior in terms of the ability to inhibit colony growth.Samples with nano-TiO2, this classification was kept constant for up to 3 days. In these cases, the EEA quantifiable parameter reached the maximum value, i.e., 31%, for the 6% nano-TiO2 composition , P2 (1% TiO2), and even the system with the maximum nanoparticle content, P10 (12% TiO2).In the case of the P0 system, the formation of more than 10 colonies, Class 2 (++) was observed after 2 days, Class 3 (+++) confluent colonies were observed after 3 days, and also Class 4 (++++) growth was observed throughout the surface . Almost In the case of contamination with 2 in the samples.The viability of the contaminants, selection of nutrients, and temperature conditions were proven. Therefore, the identification, quantification, and comparison between their action and the results regarding the growth of the biological material, when subjected to the cementitious composites, was demonstrated, based on the retention time of the samples in the contaminated environment and the content of nano-TiOEscherichia coli, Pseudomonas Aeruginosa, and Staphylococus Aureus bacteria, namely, Streptococcus Pyogenes has also been confirmed for samples containing nano-TiO2 in the range of 2% to 5%. However, the introduction of large quantities of nanoparticles in the matrix of the composite may be on one hand beneficial in terms of antibacterial effects but, on the other hand, it is harmful as a result of the tendency of agglomeration of the nanoparticles in the matrix of the composite. Therefore, the effect of the antibacterial agent is considerably reduced.The effect of the development of the inhibition halo, when subjected to Escherichia coli, Pseudomonas Aeruginosa, Staphylococcus Aureus, and Streptococcus Pyogenes, the content of TiO2 nanoparticles in the cementitious composite matrix should be at least 2% and not more than 5% relative to the amount of cement. The possibility remains open that composite samples with more than 5% nano-TiO2 are antibacterial effective if adequate nanoparticle dispersion is ensured. This range of identified nano-TiO2 amount is consistent with reports in the literature [It was considered that for a good inhibiting activity against the development of contaminants of type terature ,54,55,56From the research performed, we can draw the following conclusions:2. Through the work process adopted, it was also possible to highlight the antibacterial efficiency of cementitious composites with different nano-TiO2 percentages and to open new perspectives in the development of self-cleaning construction materials.The results and observations presented in this paper can be a starting point for further research, consisting of a relatively fast and inexpensive semi-quantitative method for evaluating the antibacterial performance of cementitious composites with nano-TiO


The aim of this case report is to present an innovative combined orthodontic-surgical technique to disimpact mandibular second molar (MM2) using an orthodontic miniscrew and an elastic chain. The impact on the Oral health-related quality of life (OHRQoL) was also evaluated. Using the present techinique, it is possible to expose the impacted tooth, insert a self-drilling miniscrew in the retromolar area, and remove the bud of third mandibular molar. At the same time the orthodontic force is applied with the use of an elastomeric chain that connects the head of miniscrew and vestibular and oral buttons bonded on MM2. A close traction is performed for the whole treatment time without the reactivation of the elastic force. The use of skeletal anchorage allowed the disimpaction of impacted MM2 in a short treatment time (about three months) avoiding the typical biomechanical side effects of traditional orthodontic appliance and increasing the effectiveness of the treatment. Further studies are necessary to evaluate the real advantages and disadvantages of this combined orthodontic-surgical approach. Mandibular second molar MM2) impaction is an infrequent event  compared impactioto show an innovative combined orthodontic-surgical procedure to solve a moderately mesially-impacted mandibular second molar (MM2) using an orthodontic miniscrew with an elastic chain;to evaluate the impact of this procedure on the Oral health–related quality of life (OHRQoL).Management of mesially-angulated impacted MM2 often requires an interdisciplinary approach. The treatment options depend both on the degree of tooth inclination and the required tooth movement. The position of a slightly-tipped MM2 can be corrected by placing a brass wire separator between the teeth ,8,9. A mThe present procedure, used at the Department of Oral and Maxillo-Facial Sciences of “Sapienza” University of Rome, allows MM2 disimpaction employing a submucosal orthodontic miniscrew with an elastic chain. A 12-year-old Caucasian female patient was referred to the Department of Orthodontics of “Sapienza” University of Rome to solve several tooth impactions. The patient’s medical history showed nothing remarkable. The patient referred to a previous orthodontic treatment with a lingual arch in the mandible to gain space. Intraoral examination revealed a molar Class II malocclusion with not centered midlines, an overjet of 2 mm and an overbite of 5 mm. The patient showed a severe crowding of maxilla (7 mm) with no space for maxillary canines eruption. A moderate crowding was present in the mandible (6 mm). Temporomandibular joints were healthy.The panoramic radiograph showed the presence of several impacted teeth . Angle omaxillary canines impaction (1.3 and 2.3);MM2 impaction (3.7 and 4.7)The objectives of treatment were to solve:The following three treatment options to solve MM2 impaction were presented: a conventional orthodontic treatment with lingual arch with a posterior arm; a cantilever arm supported by a miniscrew or teeth; a close traction with a retromolar miniscrew connected to an elastic chain.The patient’s need was to solve the dental impactions in the shortest possible time without masticatory limitation. The treatment plan was to remove the impacted maxillary canines and to solve MM2 impaction using a combined orthodontic-surgical technique with orthodontic miniscrews and an elastic chain. The patient was informed of the risks, advantages and disadvantages of this therapeutic approach and provided written informed consent to undergo the procedures.The advantages of this technique are: the absence of orthodontic device in the oral cavity (submerged technique) allowing the maintenance of good oral hygiene without masticatory limitation. Furthermore, the orthodontic traction was not reactivated, reducing the number of appointments and improving the patient’s comfort.The main disadvantage was the need to perform a flap to remove the miniscrew.The guidelines of the declaration of Helsinki were followed. The investigation was independently reviewed and approved by the local ethics committee of Policlinico Umberto I-Sapienza University of Rome (Rif. 5951 on date 22 April 2020).The day of surgery the patient was treated by a single operator, an expert orthodontist and oral surgeon (MC). Local anesthesia with mepivacaine (20 mg/mL) associated with epinephrine in the ratio 1:100,000  was administered. A mucoperiosteal flap extending from the first molar to the retromolar area both on the buccal and lingual side was reflected to expose the bone surrounding the impacted MM2 (3.7) and the third mandibular molar (MM3) bud. Bone was carefully removed, as required, for the MM3 germectomy. Immediately afterwards, a self-drilling miniscrew was inserted in the retromolar area by a cordless screwdriver with a torque calibration system . The fixture insertion torque was set at 40 N/cm.The site and angle of insertion, the length and the diameter of titanium miniscrew  were determined in the planning phase on a panoramic radiograph  and clinically confirmed during the surgery. After the self-drilling miniscrew insertion, two metal brackets were bonded on the buccal and oral surfaces of MM2 crown. At the end of surgery an elastic chain was secured to the miniscrew head and connected to the metal brackets bonded on buccal and oral surfaces of MM2 crown A,B; a clOral health–related quality of life (OHRQoL) was assessed using the Italian version of the short-form oral health impact profile with 14 questions (OHIP-14) that represent 7 dimensions of OHRQOL: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap ,19. The Ibuprofen was recommended for pain control. Antibiotic therapy (1 gr of amoxicillin) was prescribed 1 h before intervention and twice a day for 5 days.The patient was checked every month until the uprighting of MM2 was complete.The same elastic chain was not changed for the whole time of therapy.The MM2 was considered upright when the mesial marginal ridge was above the distal contours of first mandibular molar (MM1) .At the end of therapy the miniscrew was removed  and the No important adverse events or side effects were recorded.The OHIP-14 filled out by the patient before the treatment (T0), and 3 (T1) and 7 (T2) days after surgery had a total score of 15 points . A deterioration in OHRQoL was observed only after 3 days of surgery; an improvement in OHRQoL was observed after 7 days of the procedure with almost a complete restoration (OHIP-14 = 4) of pre-treatment value.The MM2 impaction was corrected in 92 days.Management of MM2 impaction is considered very difficult and unpredictable and is a challenge for both orthodontist and oral surgeon. Close collaboration between the two specialists is needed to achieve the MM2 disimpaction. An early diagnosis and early treatment are the keys for successful correction of MM2 impaction. In addition, it is important to disimpact the MM2 as soon as it is diagnosed because of the contact with the MM1 that could cause root resorption, caries, and periodontal problems.Treatment options for an impacted MM2 can include extraction, orthodontic uprighting, surgical uprighting, and surgical-orthodontic approach ,21,22. MThe present technique allows, in a single appointment, the exposure of the impacted tooth, the insertion of the screw, the extraction of the third molar bud and the activation of the orthodontic traction.Regarding the combined use of miniscrews and elastic chains, few similar studies exist in the literature ,25. MiyaZen et al.  describeUnlike the techniques described above, the present procedure is a close traction technique. A miniscrew is inserted in the retromolar area and two brackets or buttons attachments are bonded on the crown of MM2; an elastic chain is connected from the head of the miniscrew to the two buttons, minimizing the size of the orthodontic device, reducing chair time and improving the patient comfort compared to complex segmental biomechanics. The force application generates a counterclockwise moment, allowing control of the movement and the collateral effects and, consequently, promoting rapid disimpaction and distalization of the crown.Moreover, this procedure allows an absolute control of the anchorage and no unwanted movement of adjacent teeth ,24,25.The retromolar area seems particularly suitable for screw insertion, considering the presence of compact cortical bone tissue which immediately provides excellent primary stability. According to Finotti et al., after third molar extraction, the creation of a cortico-medullar void distal to the second molar, or appositely surgically performed is important to reduce the treatment time .Nowadays, computer-guided miniscrew-supported orthodontic appliances can be realized ,28 thankIn conclusion, it can be stated that the combined use of miniscrew and elastic chains could be a valid procedure for moderate mesially-impacted MM2. In a single surgical time the MM3 germectomy, the miniscrew insertion and the orthodontic traction are performed, without a negative impact on the OHRQoL. Certainly, an early diagnosis can prevent impaction of these teeth, enabling a more conservative treatment approach, so a radiographic follow-up of the dental eruption process should be encouraged to observe an early delay in the eruption of the MM2. It must be highlighted that the efficacy of this approach must be further investigated to evaluate the real advantages and disadvantages of this technique.


When an additive is used to replace a certain amount of cement, a concrete pore structure becomes dense. Thus, it results in inhibiting the penetration of chlorine ions and suppressing corrosion of reinforcing bars. However, the pH level of the concrete decreases, and it deteriorates the performance of the passive film formed on the surface of the rebars embedded in the concrete. Therefore, in this study, the service lives of reinforced concrete containing different types of concrete binders were predicted and compared. The chloride ion diffusion coefficients of concretes with various binders were measured, and the critical chloride content of the rebar was assessed by the real-time monitoring on the corrosion initiation time of the rebar embedded in concrete. Moreover, Fick’s 2nd law was applied to predict when the chloride content at the 40 mm depth of cover reached the critical chloride content based on the chloride ion diffusion coefficient. It was observed that the service life of S6 (OPC 40% + GGBFS 60%) was the highest, followed by TBC (OPC 40% + GGBFS 40% + FA 20%), S3 (OPC 70% + GGBFS 30%), and OPC (OPC 100%). With the durability of concrete emerging as a social issue, the need to develop concrete with high durability has been coming to the fore. Of particular concern are concrete structures in areas affected by the marine environment are subject to immense maintenance costs due to the corrosion of rebars caused by the penetration of chloride ions ,2.In recent years, the demand to construct concrete structures around port facilities has increased due to the increase of goods transported by sea, so it is becoming important to build concrete structures with excellent resistance to marine environments both in terms of structural stability and in terms of economics ,4,5.Methods using such admixtures as ground granulated blast furnace slag (GGBFS) and fly ash have been proposed to improve the durability of concrete exposed to chloride attack ,23,24,25However, studies have shown that replacing the cement used in concrete with admixtures such as GGBFS and fly ash can reduce the critical chloride content of rebars embedded in the concrete ,32,33,342. The penetration rate of chloride ions was calculated using Fick’s 2nd law, and the time when the chloride content at the 40 mm depth of cover reached critical chloride content was considered as the point at which the service life of concrete terminated.In this study, the variation of the service life of reinforced concrete was evaluated according to the different types and replacement ratios of additives. The chloride ion diffusion coefficient of concrete was measured based on NT BUILD 492. In addition, the corrosion initiation time and the critical chloride content of the rebar embedded in reinforced concrete were assessed by using an embedded reference electrode with MnO3  was used. And Grade-80 Ground Granulated Blast Furnace Slag (GGBFS) of ASTM C989/C989M [2/g  was used. Class-N Fly-Ash (FA) of ASTM C 618 [2/g was also used. Ordinary Portland Cement (Type 1) of ASTM C150/C150M  with a d89/C989M  with a BTM C 618  with a BTo reduce the effect of coarse aggregates between the rebar and cover of concrete, the maximum size of coarse aggregates was limited to 13 mm and the fine aggregates were prepared by mixing crushed sand and washed sea sand. In Korea, it is common to use a combination of crushed aggregates and washed sea sand (decontaminated chloride) owing to the depletion of river sand ,58. The For this study, four types of concrete specimens were prepared according to the GGBFS and FA replacement ratio: OPC 100% (OPC), GGBFS 30% + OPC 70% (S3), GGBFS 60% + OPC 40% (S6) and GGBFS 30% + FA 30% + OPC 40% (TBC).As for the experimental level, normal GGBFS cement (replacement ratio 30%), high durability GGBFS cement (replacement ratio 60%), and three-binder combination cement (replacement ratio 60%) were compared with 100% OPC. After the concrete was mixed for specimen fabrication, it was poured into a cylinder mold (Ø100 mm × 200 mm) and sealed. The specimen was demolded 24 h later and cured for 28 days. After curing 28 days, the specimen was cut into samples 50 mm and the 2 samples from the middle of the specimen were used. 2 sensor, and finally placing concrete. Reinforced concrete specimens were fabricated to evaluate the critical chloride contents of rebars according to the concrete mixture. The reinforced concrete specimens were prepared by placing rebars in a rectangular mold (size: 100 mm × 100 mm × 200 mm) using acrylic, arranging the MnO2 sensor was placed close between two rebars and embedded in concrete along with the rebars to allow more accurate measurement with fewer errors.SD400 rebars (Ø13 mm) were used to fabricate the specimens. The foreign substances and corrosion products on the surface of the rebars resulting from long-term exposure to air were removed by using grit-blast and sandpaper. The MnOAfter mixing the concrete, it was poured into the mold and demolded after 24 h. Then, the concrete specimens were cured by air-dry curing for 28 days. The air-dry curing conditions were a temperature of 20 °C ± 2 °C and relative humidity of 60% ± 5%. In order to simulate the curing conditions of the concrete poured on the site, air-dry curing was performed, not under-water curing.The concrete compressive strength was evaluated according to ASTM C 39  for curiThe most exact method of measuring the resistance to chloride ingress of concrete is to perform an exposure test. However, exposure tests required a very long time. Therefore, it is common to evaluate the chloride ion diffusion coefficient and resistance to chloride ingress of concrete using the electrochemical acceleration method. Typically, NT BUILD 492 and ASTM C 1202 are used to evaluate chloride ingress of concrete. In this study, among the resistance to chloride ingress evaluation methods, the chloride ion diffusion coefficient was obtained from non-steady-state migration experiments conducted according to NT BUILD 492 , a Nordi2 saturated solution was filled in a desiccator and the concrete specimen was immersed in the saturated solution. The inside of the desiccator was maintained in a vacuum state by using a vacuum pump, and the pores of the concrete were filled with Ca(OH)2 saturated solution. After pretreatment, chloride ion diffusion cells were prepared as shown in l30V). Next, according to the initial values in NT BUILD 492 is a non-steady-state electric migration experiment to determine the chloride ion diffusion coefficient of the repair material composed of concrete, mortar, and cement. Concrete specimens (size: Ø100 mm × 50 mm) were prepared, Ca(OH)3 solution was sprayed on the split section, discolored parts appeared on the specimen depending on the penetration depth of the chloride ions. The chloride ion diffusion coefficient was determined using the average of seven measurements of the chloride penetration depth, in 10 mm intervals.After the test, the concrete specimen was split vertically into two pieces. When 0.1 N AgNOnssmD: non-steady-state migration coefficient (×10−12 m2/s), U: absolute value of the applied voltage (V), T: average of the initial and final temperatures in the anolyte solution (°C), L: thickness of the specimen (mm), xd: average value of the penetration depths (mm), T: test duration (h).Equation (1) is used to estimate the chloride ion diffusion coefficient at the depth of chloride ion penetration .(1)DnssThe potential (OCP) monitoring test of rebars was performed according to the NaCl supply time, and 2 sensor, an NaCl supply cell was installed on top of the specimen using acrylic, and the potential of the rebars was monitored in real-time using a Data-logger  according to the supply time of 10 wt.% NaCl solution. The wires were soldered to the rebars to monitor changes in the potential of the rebars. The rebars were connected to the anode (+) of the data-logger and the MnO2 sensor to the cathode (−) to collect and store data by measuring the potential of the rebars to the MnO2 sensor every 10 min. While observing the potential of the rebars according to the 10 wt.% NaCl solution supply time, the rebars were evaluated as corroded if the potential of the rebars dropped below −515 mV, in which case, the test was ended by stopping potential measurement and the supply of NaCl solution [After connecting wires to the rebars of the specimen and the MnOsolution . Then, tsolution ,62.The supply of NaCl solution was stopped for the 20 mm concrete cover specimens in which rebar corrosion had started and the 25 mm concrete cover specimens in which rebar corrosion did not occur. The concrete specimens were collected after cutting the specimens at 5 mm intervals from the NaCl solution supply surface, and the chloride content was measured according to ASTM C 1218  to profiAfter measuring and profiling the chloride content according to the concrete cover depth, the chloride content between the 20 mm concrete cover depth of corroded rebars and the 25 mm concrete cover depth of non-corroded rebars was estimated as the critical chloride content of the rebars embedded in concrete.V1: Volume of 0.05 N silver nitrate solution used for titration in the specimen , V2: Volume of 0.05 N silver nitrate solution used for blank titration , N: The exact normal concentration of 0.05 N silver nitrate solution (N), W: The mass of the specimen (g).Titration with silver nitrate was used to measure the chloride ion concentration in the concrete, and Equation (2) shows how to calculate the chloride content for the mass of concrete according to the appropriate amount of silver nitrate .(2)Cl− p-value is the cement mass ratio (%) in mortar or concrete, and this study used the cement mass ratio.After calculating the chloride content (%) for the mass of concrete, the chloride content (%) for the cement or binder was obtained by multiplying the chloride content (%) by 100/P. The C: Chloride ion concentration (kg/m3) at depth x (cm) and time y (year), C0: Chloride ion concentration on the surface (kg/m3), D: Chloride ion diffusion coefficient, erf: Error functionFick’s Second Law was used to evaluate the service life of the reinforced concrete structure, as shown in Equation 3) below [ below 3.(3)C of concrete can be ranked in the order of OPC > S3 > S6 > TBC, while the compressive strength after 28 days can be ranked in the order of OPC 29.2, S30 28.2, S60 27.4, and TBC 21.8 MPa, showing the same trend as the initial compressive strength. The compressive strength of concrete decreased as the admixture replacement rate increased, and with the same 60% replacement ratio, the GGBFS 60% specimen showed higher compressive strength than the TBC specimen. The development of concrete compressive strength was limited because of the insufficient hydration process under air-dry curing conditions and the absolute quantity of cement (40%), which reduced the production of Ca(OH) fly ash ,13,15. IAccording to the measurement results, the chloride ion diffusion coefficient of concrete can be ranked in the order of OPC > S3 > TBC > S6, and replacing OPC with GGBFS or FA was shown to be effective in reducing the number of ions penetrating the concrete. However, when replacing GGBFS 40% + FA 20%, the chloride ion diffusion coefficient was not significantly different from the GGBFS 30% specimen even though the replacement rate was 60%. This is because the latent hydraulic property of GGBFS and the pozzolanic reaction of FA did not occur sufficiently due to the decrease in the absolute quantity of cement and the hydration products under the high admixture replacement rate and air curing conditions, so the structure of the cement matrix was not completed properly ,18,19,202) as the NaCl solution supply time increased, and rebar corrosion occurred accordingly. On the other hand, the potential of the rebars with 25 mm concrete cover depth was stable and rebar corrosion did not occur. The time it took for the rebars with 20 mm concrete cover to corrode according to the NaCl solution supply time was 76 days for OPC, 96 days for TBC, 112 days for S3, and 119 days for S6, which has the same trend as was shown in the evaluation of the concrete chloride ion diffusion coefficient in 2 sensor was considered to be valid and accurate. In addition, improving the precision of the MnO2 sensor should allow us to correct this difference in the future [e future .In particular, since the surface of the rebars with 25 mm concrete cover depth remained intact and without corrosion, the critical chloride content that induces rebar corrosion in concrete can be roughly estimated by measuring the chloride content in the 20–25 mm concrete cover.The specimens in which the rebars started to corrode were cut at 5 mm intervals from the NaCl solution supply surface to collect the concrete samples and evaluate the amount of chloride content, and the results are shown in 3. This shows that critical chloride content for rebars embedded in concrete decreases as the replacement rate of GGBFS or FA increases. Compared to the specimen using 100% OPC, the critical chloride content of the specimen using OPC 40% + GGBFS 60% decreased by 51.37%.The concrete chloride content tended to decrease as the cover depth increased at all of the experiment levels, and the chloride content in concrete decreased as the cement admixture replacement rate increased. Among the chloride content measurement results, the chloride content between the 20 mm cover depth with rebar corrosion and the 25 mm cover depth without rebar corrosion was estimated as the critical chloride content that induces corrosion of rebars embedded in concrete. From highest to lowest, the calculated critical chloride content for rebar corrosion can be ranked in the order of OPC 1.46, S3 0.98, TBC 0.74, and S6 0.71 kg/m2 produced by hydrated OPC stimulates a latent hydraulic reaction or is consumed by the pozzolanic reaction, so the total amount of Ca(OH)2 in the concrete decreases and the pH of concrete decreases accordingly. The reduced amount of Ettringite and Ca(OH)2 produced by the decrease in the absolute quantity of cement also has a direct effect [This is because as the replacement rate of GGBFS or FA increases, the Ca(OH)t effect ,33,34,353), and the results are shown in the table below. In addition, This study evaluated the service life against chloride attack for reinforced concrete structures with 40 mm concrete cover using the results of assessing the concrete chloride ion diffusion coefficient according to the admixture replacement rate and admixture type measured in Based on the results shown above, the 3) is applied, the service life of the structures can be evaluated as 26 years for OPC concrete, 53 years for S3 concrete, 80 years for TBC concrete, and 102 years for S6 concrete. However, after critical chloride content according to the admixture replacement rate and the type of admixture is applied, the service life of the structures changes to 26 years for OPC concrete, 51 years for S3 concrete, 60 years for TBC concrete, and 89 years for S6 concrete. In the case of OPC, the service life tended to increase compared to when the conventional critical chloride content in the Korean specification was applied, but in general, the service life tended to decrease when replacing cement with admixtures.When the critical chloride content in the Korean concrete standard specification By measuring the chloride ion diffusion coefficient of concrete, it was found that the chloride ion diffusion coefficient decreased as the additive replacement ratio increased. It is judged that the pore-filling effect of concrete was due to the high fineness of GGBFS and FA. This was considered to be due to the effect of blocking the penetration of chloride ions while filling the capillary pores according to the formation of C–S–H hydrate by the latent hydraulic properties.Through evaluating the critical chloride content of the rebars embedded in concrete, it was found that the critical chloride content to induce rebar corrosion decreased as the admixture replacement rate increased. This was because the pH of concrete was reduced before hardening as the absolute quantity of cement decreased, and the performance of the passive film formed on the surface of the rebars was reduced.Applying the concrete chloride ion diffusion coefficient according to the additive replacement ratio and the additive type and the critical chloride content that initiates rebar corrosion in this study will enable a more accurate evaluation and prediction of service life compared to the use of conventional standards (0.4% of binder). As a result, the calculated service life of concrete was S3 89 years, TBC 60 years, S3 51 years, and OPC 26 years.It was confirmed that the service life of reinforced concrete is more affected by the chloride ion diffusion coefficient than the critical chloride content. However, it was confirmed that the effect of reducing the amount of critical chloride content of reinforced concrete according to the additive replacement ratio. In order to accurately design the durability of reinforced concrete structures using additives, it is considered that continuous research on critical chloride content is necessary.


This experimental research investigated the applicability of the liquid crystal display (LCD) by-product of the refining process as a sustainable and alternative alkali activator for ground granulated blast-furnace slag (GGBFS) blended cement concrete. Three levels of binder replacement using the industrial by-product, and four water/binder ratios were considered in order to evaluate the effects of the replacement in fresh and hardened properties of the blended concrete. XRD and TG analyses confirmed that the by-product that contains abundant alkali compounds promotes the reactivity of GGBFS. The test results indicated that the incorporation of the by-product results in delayed setting and degraded workability due to the highly porous nature of the by-product, yet shows rapid early-age strength development of the blended concrete as conventional alkaline activators for GGBFS. These characteristics shed light on a simple yet effective and practical means of reusing the industrial by-product as an alternative alkaline activator. It is well known that the replacement level of cement with SCMs depends on the reactivity, local availability, and legislation . For theproducts ,4,5,6,7—products ,9. 2O·rSiO2), sodium carbonate (Na2CO3), and sodium sulphate (Na2SO4) are effective and common ones used to activate GGBFS [Various alkali activators have been suggested for adequately promoting strength of blended concrete using SCMs to either partially or fully replace ordinary Portland cement (OPC). For example, it is well known that sodium hydroxide (NaOH), sodium silicate  waste glass to partially replace OPC [The current mainstream liquid crystal display (LCD) design primarily consists of color filter (CF) substrate glass on which RGB pixels are deposited and of thin-film-transistor (TFT) substrate glass that is painted with thin film circuitry that delivers signals to liquid crystal. In order to maintain a high quality and a high resolution, TFT uses an alkali-free glass that is obtained through a high refining process that involves the generation of by-product. Because the by-product of this refining process contains a large amount of alkali ingredients—such as SOlace OPC ,16,17,18lace OPC  tested uIn this study, the applicability of the LCD by-product of the refining process as an alkali activator was evaluated by characterizing the reactivity of GGBFS with OPC under a normal curing condition with the aim of developing practical applications. The binary paste was prepared by mixing GGBFS and OPC with the LCD by-product-based activator (LCDBA) and the variation of the hydration products in the paste, according to the curing age, was characterized through X-ray diffraction (XRD) as well as through thermogravimetry and differential thermal analysis (TG-DTA). In addition, fresh and hardened properties of OPC-slag concrete, activated by the alkali by-product, were assessed by examining the slump, bleeding, setting time, and compressive strength of concrete. The applicability of the LCDBA was investigated with the aim of developing practical applications as a sustainable and alternative alkali activator for GGBFS blended cement concrete. The activation effects of the LCDBA were characterized using GGBFS blended cement paste. In addition, the fresh and hardened properties of GGBFS blended cement concrete incorporating LCDBA were investigated.2/kg and 449 m2/kg and a density of 3150 kg/m3 and 2910 kg/m3, respectively. The major chemical components of GGBFS were CaO, SiO2, and Al2O3, as shown in 2 + Al2O3)) was 0.977, which is similar to the neutral value of 1.0 for ideal alkali activation [2O3)/SiO2) of GGBFS, was 1.92. This was higher than the value of 1.4, which is required for good hydration properties of GGBFS [2/kg and a density of 2540 kg/m3. XRD analysis was performed to determine the nature of LCDBA, as shown in 2SO4 and Na2SO4. The particle size distributions of GGBFS and LCDBA are shown in OPC (ASTM C 150 Type I) and GGBFS were used as binders to prepare the paste and concrete and their chemical compositions are summarized in tivation . The hydof GGBFS . The LCDNon-reactive river sand, with a specific gravity of 2.62, a fineness modulus of 2.77, and an absorption capacity of 1.1%, was used in preparation of all mortars and concrete. The crushed basalt aggregates were adopted as the coarse aggregate for the concrete mix in which the maximum size, specific gravity, absorption capacity, and fineness modulus were 25 mm, 2.63, 0.8%, and 6.4, respectively. In addition, a polycarboxylate-based superplasticizer with 17% solid content by weight was used to enhance particle dispersions within the mixture. The characterization of the reactivity of the binders was carried out based on XRD and TG-DTA tests using GGBFS blended cement paste with the OPC/GGBFS ratio of 55:45 and the water/binder ratio of 30%. LCDBA replaced the binder by 0%, 3%, and 5%. The reactivity of the paste with different LCDBA substitution levels was investigated through XRD and TG analysis. GGBFS blended cement pastes were cured at 20 ℃ and 90 ± 2% relative humidity for a predetermined curing duration . Thereafter, the samples were ground and immersed in acetone to stop hydration and were suction filtered using an aspirator. The crushed samples that stopped hydration were ground further and powdered to particles smaller than 106 μm for the XRD and TG measurements. XRD was conducted using a D/MAX 2500V/PC  with a scan range of 5°–65° 2θ. TG was conducted using a NETZSCH STA 409 C/CD  with a heating rate of 5 ℃/min in the 20–1000 ℃ range. The fresh properties of GGBFS blended cement concrete were measured using the slump, bleeding, and setting time. The slump of fresh concrete were measured in accordance with ASTM C 94 . The bleThe diffraction patterns of the hardened pastes were analyzed by characterizing the crystal phases in order to investigate the applicability of LCDBA with high alkali content for stimulating GGBFS. The activation effect of LCDBA for GGBFS can be demonstrated by investigating the generation of hydration products for different curing ages. 2Mg(Si2O7)) with strong peaks in the XRD analysis. It has been reported that akermanite exists in a crystalline form in raw materials and hardened GGBFS pastes [As can be seen in S pastes ,25 and t2)—is known to play a role in promoting the activation reaction of GGBFS [2 at 3 days decreases as the curing age increases through the consuming necessary for the activation of the GGBFS to form calcium-silicate-hydrate (C-S-H) gel. The pastes of the two series containing LCDBA also had high Ca(OH)2 at their early age and the amount decreased as the age increased. However, the decrease of Ca(OH)2 was smaller than that of LCDBA-0% series, although the C-S-H gel peak increased significantly. This phenomenon was the likely cause of the high alkaline LCDBA activator. In the section where 2θ is around 9°, it is known that ettringite peaks result from the hydration of cement [3, as with the high SO3 content in LCDBA, at 47.1%. In addition, Mohammed and Safiullah [3. In addition, the strong alkali compound of the cement hydration product—calcium hydroxide (Ca(OH)f cement . It shouafiullah  revealed2 to CaO [The degrees of hydration of GGBFS blended cement pastes were evaluated using the thermogravimetry method and the results are presented in 2 to CaO . 2, was relatively less consumed in the LCDBA-3% and LCDBA-5% mixtures due to the additional supply of alkaline compounds by LCDBA. In the meantime, it should be noted that the differences in mass change between the pastes with LCDBA and without LCDBA at 28 days were relatively large in Section I in comparison to those in Section II. This might be attributed to the fact that, as curing age increases, the alkali components supplied for the pozzolanic reaction of GGBFS in the LCDBA-3% and LCDBA-5% series were also consumed, resulting in a Ca(OH)2 decrease and reaching similar remaining levels of Ca(OH)2 as those of the LCDBA-0% series at 28 days of curing. From the results for Sections I and II, it can be seen that the weight losses of the LCDBA-3% and LCDBA-5% series are more pronounced than those of the LCDBA-0% series for all curing ages. Therefore, the large mass change in Section I implies that a large amount of C-S-H gel initially forms due to the incorporation of LCDBA that contains abundant alkali compounds that promote the reactivity of GGBFS. The large mass change in Section II can be explained that the cement hydration product, Ca(OH)The slump test is widely used and the most well-known test to assess the workability of concrete. In this study, the effect of the LCDBA usage on workability was evaluated using the slump test. The bleeding of concrete, a necessary part of the life of concrete, was considered to occur when the mix water would raise to the surface of freshly placed concrete. It has been reported that the bleed rate and capacity of GGBFS blended cement concrete highly depends on the GGBFS replacement level and the water/binder ratio . Figure The effect of the LCDBA replacement level on the initial and final setting times of GGBFS blended cement concrete is shown in The compressive strength development of GGBFS blended cement concrete with different LCDBA replacement levels and with water/binder ratios at 3, 7, 28, and 91 days is shown in The rates of increase in the compressive strength of the concrete incorporating LCDBA relative to the strength of concrete without LCDBA were evaluated for each curing age, with the results summarized in a and b are material constants considering the type of binders and curing methods, calculated in this research based on regression analysis using measured values. In addition, t and 28 days, respectively. In order to quantitatively analyze the strength developing characteristics of GGBFS blended cement concrete incorporating LCDBA, the compressive strength prediction model suggested in ACI 209 was used. The ACI Committee 209  recommenThe concrete mixtures with 5% LCDBA replacement and without LCDBA were considered to quantitatively illustrate the effect of LCDBA on the development of the compressive strength of concrete. a and b were used to further analyze the strength development patterns of the tested concrete. The calculated material constants a and b are illustrated in a and b considerably correlate with the strength development of concrete at early age and at long-term age, respectively [a is inversely proportional to the initial strength development and b is inversely proportional to the increase in compressive strength according to the curing age. As shown in the figure, a and b tend to decrease and increase, respectively, as the water/binder ratio increases. As the water/binder ratio decreases, the initial strength development rate becomes high, which leads to a decrease in a. On the other hand, the material constant b is related to the long-term strength development, where the lower b value stands for the higher long-term strength increment. The constant b values for the mixtures with LCDBA were similar, regardless of the water/binder ratio, and higher than those for the mixtures without LCDBA. The higher b values for the mixture with LCDBA were attributed to the higher initial strength development activated by LCDBA and to relatively less long-term strength development. This is similar to the strength development characteristics of GGBFS and/or fly ash blended cement concrete activated using conventional alkali activators. Therefore, it can be concluded that LCDBA is an effective and sustainable alternative to alkali activators for GGBFS blended cement concrete.As a result of the regression analysis of the compressive strength, according to the ACI 209 model, the R-squared values for the mixtures with and without LCDBA were higher than 0.985, indicating a high goodness of fit. With the high goodness of fit, the material constants ectively . Mathema(1)2 due to the stimulation of GGBFS hydrations with LCDBA as days of curing increase, were characterized using XRD analysis. This finding highlights the role of LCDBA as an activator for GGBFS blended cement concrete by providing the essential chemical evidence.The effectiveness of LCDBA as an alternative and sustainable alkaline activator for GGBFS blended cement concrete was demonstrated for the first time in this study. The formations of akermanite and ettringite, as well as the consumption of Ca(OH)(2)2, was relatively less consumed due to the incorporation of LCDBA that contains abundant alkali compounds that promote the reactivity of GGBFS. As curing age increased, the remaining amount of Ca(OH)2 in the pastes with LCDBA became similar as to the one in the pastes without LCDBA, which is another implication of the relatively less long-term strength development.The thermogravimetric analysis was employed to evaluate the degrees of hydration. The results highlight that a large amount of C-S-H gel was initially formed and that the cement hydration product, Ca(OH)(3)It is identified from this research that by incorporating LCDBA, the fresh GGBFS blended cement concrete showed degraded workability, delayed bleeding ends, reduced bleeding capacity, and delayed setting times, attributed to the porous nature of LCDBA that led to mix water absorption.(4)The series of compressive strength tests conducted in this research concluded that LCDBA was an effective alkaline activator for GGBFS blended cement concrete, showing early-age strength developing characteristics, especially for mixtures with lower water/binder ratios. The compressive strength model, suggested by the ACI Committee 209, also highlighted the early-age strength developing characteristics of the blended concrete activated with LCDBA.This experimental study evaluates the LCD by-product of the refining process, LCDBA, as an alternative and sustainable alkaline activator for GGBFS blended cement concrete. To investigate the applicability of this the alternative activator, the tested experimental parameters were set at three LCDBA replacement levels and four water/binder ratios. The activation effects were characterized based on XRD and TG analyses using GGBFS blended cement paste. The fresh and hardened properties of GGBFS blended cement concrete incorporating LCDBA were investigated using slump, bleeding, setting time, and compressive strength tests. The key observations and findings of this research can be summarized as follows:The results obtained in this study provide a simple, yet effective and practical, means of reusing an industrial by-product as an alternative alkaline activator for GGBFS blended concrete. Further studies are, however, necessary to determine its long-term durability and dimensional stabilities, such as shrinkage and creep.