This study showed the significant impact of pandemic restrictions on reducing overall compliance and physical activity, and increasing screen time among Brazilian children and adolescents.The 24-Hour Movement Guidelines provide specific recommendations on movement behaviors for children and adolescents. The objective of this study was to verify the adequacy of children and adolescents to the guidelines for moderate to vigorous physical activity, recreational screen time, and sleep duration, and the overall adequacy to the guidelines, before and during the COVID-19 pandemic. A cross-sectional study was conducted with parents or guardians of children or adolescents from different regions of Brazil using a digital interview form including sociodemographic characteristics of families, moderate to vigorous physical activity, recreational screen time, and sleep duration before and during the pandemic. Statistically significant variation was observed in both groups in relation to moderate to vigorous physical activity and recreational screen time between the two periods evaluated. Overall adequacy to the guidelines before the pandemic was 19.28% for children from Group 1 (0–5 years old) and 39.50% for those from Group 2 (6 to 17 years old). During the pandemic, it corresponded to 3.58% in Group 1 and 4.94% in Group 2 ( The 24-Hour Movement Guidelines were published by the Canadian Society for Exercise Physiology in 2016  also pubThe 24-Hour Movement Guidelines build on available evidence regarding the importance of all movement behaviors in promoting population health rather than movement behaviors alone ,12. The Since the outbreak of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), the routines of Brazilian children and adolescents have been directly impacted by measures to prevent contagion and combat the spread of the virus . Social Thus, a sample of Brazilian children and adolescents was evaluated for MVPA practice, recreational screen time, and sleep duration, as well as the overall adequacy to all three components. The objective of this study was to verify the adequacy to the recommendations of the 24-Hour Movement Guidelines at two time points: before and during the COVID-19 pandemic.This was a cross-sectional study conducted between September 2020 and January 2021. A convenience sample composed of parents or guardians of children and adolescents aged up to 18 years old who agreed to complete a questionnaire electronically sent via social networks was recruited from different geographic regions of Brazil. The non-probabilistic sampling technique (in which the participants are volunteers) was based on a “snowball” data collection process [This study was approved by the Ethics Committee for Research with Human Beings of the Fernandes Figueira National Institute of Women, Children, and Adolescents , and was based on The Checklist for Reporting Results of Internet E-Surveys (CHERRIES)  and The The electronic form for data collection was developed on a digital platform (Google Forms) and consisted of 46 variables that were used to collect information on behaviors before and after March 2020, when the COVID-19 pandemic was declared in Brazil. The electronic questionnaire was sent between September and December 2020 to the parents or guardians of children aged 0 to 5 years (Group 1) and between October 2020 and January 2021 to the parents or guardians of children or adolescents between 6 and 17 years old (Group 2). The form contained closed questions and the filling in of the questionnaire by the participants lasted about 20 min.Sociodemographic variables of the parents and guardians of children and adolescents were collected as follows: region of the country ; age; sex ; ethnicity ; higher education ; participation in distance learning ; employment status at the date of completion of the form and variation from March 2020 (employed/unemployed); remote work ; current average family income ; loss of family income from March 2020 .The mean MVPA time, recreational screen time, sleep duration, and the three parameters combined were categorized as adequate or not adequate before and during the COVID-19 pandemic according to the 24-Hour Movement Guidelines. The question about average MVPA time provided five answer options: less than half an hour a day; half an hour a day; 1 h a day; 1.5 h a day; more than 1.5 h a day. The average daily screen time  was assessed using seven options: none; less than 1 h; 1 h; 2 h; 3–4 h; 5–7 h; more than 8 h). Average sleep duration (including naps) was assessed using five options: 15 or more hours a day; 13 to 14 h a day; 11 to 12 h a day; 8 to 10 h a day; less than 8 h a day.MVPA: For infants who are still unable to walk: 30 min throughout the day in the prone position (belly down) or playing sitting away from the screens; for children aged between 1 and 2 years: at least 180 min of MVPA throughout the day; from the age of 3: 60 min of MVPA.Recreational screen time: For children under 2 years: exposure to digital screens is not suitable; between 2 and 4 years: up to one hour a day, with no exposure being better; 5 years or older: not exceeding two hours a day of exposure to digital screens.Sleep duration (including naps): Between 0 and 3 months of age: 14–17 h/day; 4–11 months of age: 12–16 h/day; 1–2 years: 11–14 h/day; 3–5 years: 10–13 h/day; 6–13 years: 9–11 h/day; 14–17 years: 8–10 h/day.Overall adequacy: status of simultaneous adequacy to MVPA, recreational screen time, and sleep duration guidelines for each participant.The main outcomes were adequacy to the recommendations of the 24-Hour Movement Guidelines regarding MVPA, recreational screen time according to the type of device , sleep duration, and overall adequacy to these three components ,4. The fData were stored in an electronic spreadsheet created automatically by Google Forms, which was exported in Excel format for further analysis using the JASP 0.16.1 statistical package. The categorical variables were described by their respective frequencies of occurrence (absolute and relative) and numerical variables by the means and standard deviations. The chi-square and McNemar’s tests were used to evaluate differences in MVPA adequacy, recreational screen time, sleep duration, and overall adequacy before and during the COVID-19 pandemic.From the 525 parents or guardians who participated in this study, answers were obtained regarding 363 children aged 0 to 5 years (Group 1) and 162 children or adolescents aged 6 to 17 years old (Group 2). The mean age of parents or guardians was 37.71 years for Group 1 and 44.21 for Group 2. The remaining sociodemographic characteristics of participants are shown in p-value < 0.001) of MVPA in both groups observed when comparing the periods before and during the pandemic . Group 1 started using TVs more than any other screen type . During the pandemic, both groups evaluated showed a statistically significant reduction in the adequacy to recommended screen use time, regardless of the device used  in either group. However, about 50% of the children in Group 1 were adherent to the guidelines before the pandemic, with a small reduction of this percentage (47.38%) during the pandemic period. Children in Group 2 presented 82.72% adequacy before and 86.42% during the pandemic  in both groups . There wBased on the information provided by parents and guardians, this study supports the hypothesis that behavioral changes resulting from the COVID-19 pandemic significantly interfered in the overall adequacy to the recommendations of the 24-Hour Movement Guidelines. Objectively, there was a negative impact in relation to physical activity, recreational screen use time, and the overall adequacy to the three components. The inadequacy of the above-mentioned guidelines has been considered to be a risk factor for overweight and for changes in children’s neurocognitive functioning [Regarding the adequacy of individuals to recommended levels of physical activity before and during the pandemic, a reduction was found. Similarly, other studies have reported a decrease in the proportion of children and adolescents who complied with the MVPA guidelines ,26,27,28Regarding screen time, considering the different types of screens, the use of TV presented the greatest decrease in adequacy. These results are aligned with the evidence showing that sedentary behavior increased worldwide during the pandemic ,39,40,41Regarding sleep time, no statistically significant reduction was observed between the periods evaluated, but the present study produced an unexpected finding: the adequacy to the recommendations was already extremely low before the pandemic, especially in children under 6 years of age. The systematic review by Kharel et al. (2022) evaluated only studies that were conducted during the pandemic and showed variable results regarding sleep duration: increased daily sleep duration among children and adolescents in Chile, Spain, Singapore, and Italy, and preschoolers in China; decreased sleep in the UK and Poland; and no significant difference in sleep duration among children and adolescents before and during the pandemic in other studies in Spain, Australia, USA, Portugal, and China . It is iOverall adequacy to the recommendations of the 24-Hour Movement Guidelines was already challenging in several countries before the pandemic ,59,60,61Other studies have also found a significant reduction in the proportion of children and adolescents of different nationalities who conformed to all of the 24-Hour Movement Guidelines during the restrictions imposed in response to COVID-19 ,41,63,64It is important to point out that the recommendations of distance learning and social isolation made in response to COVID-19 affected the participation of children and adolescents in physical education, sports, and other forms of MVPA related to their school or community activities. However, it should be noted that in the adequacy analysis of the present study, the distance learning hours adopted by several schools were not included, because it was understood that there was no viable alternative for formal education. If these hours were included, the percentage of adequacy in the present study would have been even lower.Online surveys are a promising tool for health research; this survey allowed the participation of individuals from all over the country, especially at a time when it was not possible to conduct face-to-face research due to the social distancing measures in force in Brazil at the time of data collection.Emerging evidence shows that overall compliance with the 24-Hour Movement Guidelines can lead to health benefits. Considering that the information available on the subject among children and adolescents from low- and middle-income countries is scarce, the strength of this study is in the identification of the overall adequacy to the recommendations of the 24-Hour Movement Guidelines among a Brazilian sample. However, the limitations of this study should be recognized. First, online surveys may be subject to bias resulting from the following issues: (1) the non-representative nature of the internet population; (2) self-selection of participants (voluntary effect), since people who do not have access to the Internet have a null probability of selection and, as the participants were volunteers, the selection probabilities and the non-response rate could not be estimated; and (3) online surveys allow the collection of valuable information during critical periods, but the veracity of the responses in this study may be subject to recall bias, since information on habits prior to the pandemic was requested.A further limitation is that one in four people in Brazil does not have access to the internet. In total numbers, this represents about 46 million Brazilians (25.3%). In rural areas, the rate of people without access is even higher than in cities, reaching 53.5%. In urban areas it is 20.6% . In addiThe overall adequacy to the recommendations of the 24-Hour Movement Guidelines regarding MVPA, recreational screen time, and sleep duration was not satisfactory before the COVID-19 pandemic, with worse results during the pandemic. Social isolation measures contributed to the reduction of physical activity and to the increase of screen time among Brazilian children and adolescents. Therefore, we recommend education regarding the importance of physical activity, reducing the use of screens, and adequate sleep time according to the age group. The monitoring of actions aimed at children, adolescents, parents, schools, and health professionals should be encouraged to achieve healthier lifestyles and the improvement of habits related to health and school performance beyond the pandemic scenario.


Advances in cell culture media have led to a trend of embryo transfer from the early cleavage stages to blastocyst stage.The study aims to compare the effects of fresh embryo transfer in cleavage and blastocyst stage on pregnancy outcomes. This cross-sectional study was conducted on 1422 cases referred to the Umm-al-Banin Infertility Clinic Center, Dezful, Iran, between July 2013 and December 2020 who were candidates for in vitro fertilization/intracytoplasmic sperm injection for fresh embryo transfer. A total of 1246 cases were divided into 4 categories on days 2-5 or 6. Chemical and clinical pregnancy, abortion, multifetal pregnancy, ongoing pregnancy, and live birth rates were analyzed.Fresh embryo transfer was performed in 28.5% of the cases on the 2According to the results, the consequences of pregnancy in fresh embryo transfer at the blastocyst stage were not superior to embryo transfer at different stages of the cleavage process.  Infertility associated with reproductive disorders is a pervasive problem in human societies, defined as the absence of pregnancy after 1 yr of regular intercourse without using contraception (1). In recent decades, the increasing demand of infertile couples for fertility has urged the development of various fertility technologies in treating fertility in vitro.Embryo transfer and subsequent in vitro fertilization (IVF) are classically done at the cleavage on day 2 or 3 after fertilization, which is in the cell stage or the blastocyst stage, on days 5-6 (2). On the other hand, better pregnancy outcomes could be attained by defining another standard for the simultaneous transfer of more than one embryo, resulting in multiple births, along with consequences such as abortion or premature birth (3).Evidence suggests that if the blastocyst is transferred to the uterus instead of the embryo in the cleavage stage, as developmental stages are fully monitored in the laboratory, the possibility of synchronizing the uterus to accept the embryo will further increase (3). On the other hand it is very similar to a natural phase and allows embryo self-selection after stimulation of the embryonic genome on day 3 (4). Current advances in cell culture media have conducted to a shift in the early embryo whereas transfer process from the cleavage stage to the blastocyst stage in IVF . A recent study has indicated that since the morphological grade of the embryo in the cleavage and blastocyst stages cannot show chromosomal abnormalities; therefore, embryos with chromosomal defects may also progress to the blastocyst stage (5). Despite good reports on the prognosis of blastocyst embryo transfer (BET) programs, one study has shown that prolonged embryo culture, which can precede to a number of embryos failure to blastocyst stage, in vitro culture beyond embryonic genomic activation caused epigenetic effects on the embryo, and also an increased rate of transfer cessation and risk of monozygotic twins (4).Embryo transfer was conventionally performed 2 days following oocyte retrieval, while changes in cell culture media allow embryos to be kept for longer times Delayed transfer from the 2Due to the contradictions in various studies regarding the consequences of embryo transfer in the cleavage and blastocyst stages, the present study aimed to retrospectively assess the records of the cases referred for embryo transfer to Dezful Infertility Center within the past 7 yr and review the outcomes of fresh embryo transfer in different stages of development.In this cross-sectional study, the files of 1246 women who were candidates for IVF/intracytoplasmic sperm injection (ICSI) processes in the Umm Al-Banin Infertility Center in Ganjavian hospital, Dezful, Iran between July 2013 and December 2020 were studied.The required data were collected by extracting information from the files of the participants based on the stage of the transferred embryo and completing checklists. The embryos of these individuals were transferred on days 2, 3, 4, and 5 or 6, depending on the policy of the infertility center. The pattern used in the study was based on the Strobe guideline checklist.The participants aged between 20 and 43 yr were scheduled for fresh embryo transfers. Ladies with endocrine and metabolic condition; follicle-stimulating hormone concentration of Using the antagonist protocol, controlled ovarian stimulation (COS) was performed as per the conventional method (7). Oocyte retrieval was done transvaginally 36 hr later subcutaneously injecting 250 µg of recombinant human chorionic gonadotropin (rHCG) vial  under ultrasound guidance.Following oocytes collection, oocytes were denuded and incubated as a traditional method. Then denuded oocytes were verified for the nuclear status. The oocytes were scored via an inverted microscope  (7). The oocytes were inseminated and subsequently incubated in the culture media. They were then assessed to confirm the show of pronuclei and fertilization 16-18 hr after using a Nikon inverted microscope .An expert embryologist evaluated the embryo quality, and the embryos for transfer were chosen in the opinion of morphologic features. Embryos were scored according to Hill's standards (8). On day 5, the blastocyst scoring system was used according to the standards of Gardner and School craft. This is centered on the creation and scale of expansion from early to totally expanded blastocyst of the blastocoele, the progress of the inner cell mass, and trophectoderm. The pooled score varied from 1-4 (A-D), with greater scores representing bad quality; embryos with a score of 4 (D) were not transferred (9).After embryo grading, based on the embryo quality, age of women, and previous history of IVF failure, the number of transferred embryos was determined between 1 and 3. According to the clinics policy, embryo transfer at the blastocysts stages are performed at the request of the couple when there are at least 6 grade A/B embryos, severe male factor is absent, and patient has no history of more than 3 unsuccessful embryo transfers.Fresh embryo transfer was performed 48-144 hr after ovum pick up by transabdominal ultrasonography guide by the single gynecologist with the same catheter as conventional method (10).Participants were divided into 4 groups based on the stage of the transferred embryo. The first group of embryos was in the 2-day stage (group 1), the second group of 3-day embryos (group 2), the third group of 4-day embryos (group 3), and the 4The determined outcomes contained a chemical pregnancy rate, which was considered as a serum beta human chorionic gonadotropin level Additionally, participants data were also extracted from their files, including the cause of infertility, estradiol levels, number of total and mature oocytes, number and quality of the transferred embryos, chemical and clinical pregnancy rate, miscarriage rate, ongoing pregnancy rate, rate of live births, and multifetal pregnancies.Prior to starting the IVF/ICSI process, the couples signed the informed consent forms. The study was approved by the Ethics Committee of Dezful University of Medical Sciences, Dezful, Iran (Code: IR.DUMS.REC.1398.040).Data analysis was performed in Social Sciences software version 25.0 . Data were presented as mean A total of 1246 participants fulfilling the criteria defined in materials and methods participated in this study and received embryo transfer.The subjects were divided into 4 groups based on the embryo transfer day, including on day 2 (group 1 = 355 (28.5%), on day 3 (group 2 = 571 (45.8%), on day 4 (group 3 = 191 (15.3%) and on day 5 or 6 (group 4 = 129 (10.4%). Table I presents the demographic characteristics of the patients. The mean age of women and men was 33.12 Table II shows the participant's cycle characteristics. No significant differences were observed in terms of estradiol levels on the day of HCG injection, the number of follicles, recovered oocytes, the number of metaphase II oocytes, total number of embryos, number of transferred embryos, and score of transferred embryos. According to the findings from a total of 2437 obtained embryos, 1175 embryos (48.2%) had A quality, 703 (28.8%) had B quality, 480 (19.7%) had C quality, 79 (3.3%) had D quality that were eliminated for transfer. The distribution of transferred embryos was the same in all groups.Table III shows the comparison of fertility and its consequences based on the age of the transferred embryo. No difference was observed between groups regarding chemical and clinical pregnancy rates p = 0.96, p = 0.89, respectively. Regarding ongoing pregnancy and live birth rates, results were indicated despite the lower rates of ongoing pregnancy and live birth in groups 3 and 4, this difference was not significant p = 0.78, p = 0.4, respectively. It was expected that the highest and lowest rates of multiple pregnancies were seen in groups 4 and 1, respectively; however, no significant difference was observed in this regard (p = 0.19). Our findings indicated that no correlation was observed between the developmental stage of transferred embryos and multiple births. According to the obtained results, the highest percentage of abortions was observed in group 3, although this rate was not significantly different from the other groups (p = 0.54).Recent advances in cell culture have led to a shift in IVF from embryo transfer in the initial stages of cleavage to embryo transfer in the blastocyst stage. In terms of blastocyst culture and its transfer theory, this approach could improve the synchrony between the fetus and uterine endometrium. Our findings among 1246 eligible cases indicated no significant correlation between pregnancy outcomes and the embryo's developmental stage in embryo transfer cycles.Research in participants aged In a study to investigate the possible impact of COS on the perinatal outcomes in 784 fresh transfers and 382 freeze-thawed dual blastocyst transfers showed clinically significant differences concerning the peri-implantation and perinatal outcomes of fresh and freeze blastocyst transfer, due to better endometrial receptivity and placentation in freeze-thawed cycles (12). This discrepancy could be due to the selection of fresh embryo transfer in this study that can be an effect of COS on implantation rate and pregnancy outcomes.In another retrospective study of 11,801 cases that underwent cleavage-stage embryo transfer (CSET) and 1009 cases that underwent BET concluded no evidence to support the superiority of BET compared with CSET in a freeze-all treatment scenario about living birth rate or by increasing the risk of preterm delivery in BET (13). The findings of the mentioned study, which have been reviewed in a trial study, are consistent with our findings. Despite the selection of cases with frozen embryo transfer in this study, the results are consistent with our study. In this way, eliminating the effect of COS on implantation as the confounding factor further confirms the results of our study.In a randomized controlled open label pilot clinical trial research, the investigators showed that the transfer of blastocyst-stage embryos in recipients of donated egg is preferred to a higher clinical pregnancy rate, live birth rate, shorter time to pregnancy, and lower costs to succeed live birth, compared with CSET (14). These findings are in contrast with the results of our study.One retrospective study about the assessment of the cumulative mean rate of live births in 377 embryos transferred on day 3 and 623 embryos transferred on day 5, showed no significant difference in the rate of live births between the 2 groups (15). This finding is consistent with our results that showed the rate of live birth in the cases where 2 days old embryo was estimated at 19.1%, while it was 20% with 3 days old embryo, 14.1% with 4 days, and 14% with 5 or 6 days; however, the difference in this regard was not considered significant.The results of the one retrospective cohort study show that embryo transfer in the blastocyst stage increases the chance of live-birth rate by 1.49 times. At the same time, it also increases the probability of preterm birth by 16%. The probability of clinical pregnancy also increases by 1.68 times (16). These results are not consistent with our results in this research; the average rate of live births at the cleavage and blastocyst stages was 17.6% and 14%, respectively. However, the increase in the fertility rate did not change significantly. The fertility rate based on the fetal heart development was estimated at 20.6% for the embryos in the cleavage stage and 17% in the blastocyst stage.Also, in contrast to these studies, the results of our study showed low ongoing pregnancy and live-birth rate on the 4On the other hand, research about live birth following blastocyst against CSET in the first cycle of IVF, results showed blastocyst transfer did not significantly affect the odds of live birth (17) that no consistent with our results in this regard. Also, findings of other studies showed that there is no significant difference between blastocyst and CSET. However, embryo transfer in the blastocyst stage is associated with a reduced likelihood of multiple pregnancies (2). In this regard, although the rate of twin pregnancies did not decrease in our study, it did not differ significantly compared to other groups. The difference in the number and quality of embryos transferred as well as the choice of patients can probably be justified.One of the limits of our analysis includes the retrospective kind. We were incapable of adjusting for several confounders, such as smoking status, body mass index. Also, this study failed to assess the cumulative live birth rate as the most valuable key performance indicator of the treatment. Also, perinatal outcomes were not included in our analyses. Advantage of the study we were able to assess the various stages of cleavage fresh embryo transfer and blastocyst stage on pregnancy outcomes. Also, all processes from the choice of cases, indications, IVF procedure, ovum pick up, and embryo transfer were done by one gynecologist that confounder caused by doing, was deleted.According to the results, the developmental stage of the fresh embryo (blastocyst or cleavage stage) for transfer had no positive or negative effect on fertility. It seems BET is not superior to cleavage embryo transfer in reproductive outcomes. However, it is suggested that similar investigations can be conducted in this regard on larger sample sizes to assess the different stages of embryo transfer, pregnancy, and perinatal outcomes.Authors declare that there is no conflict of interest.


In this study, dry chemical modification was developed to modify the gangue, and multiple characterized approaches were used to characterize the dissolution property, mineral composition, and particle size distribution of modified gangue (MCG), as well as the compressive strength and microstructure of BCM. The findings show that the residue weight of MCG stabilized at 2 wt.% of formic acid, and the modification reduces the kaolinite and calcite, resulting in smaller particles. Additionally, the three days compressive strength of the BCM made with MCG was improved from 0.3 MPa to 0.6 MPa. Attributed to the increased reactivity of MCG, it was found that the dissolution weight increased by 2.13%. This study offers a novel method for activating gangue and a new kind of MCG-prepared BCM, which makes a significant contribution towards achieving the UN Sustainable Development Goals.Gangue-based backfill cementitious materials (BCM) are widely applied due to their low CO This is due to the significant environmental impact associated with coal mining and cement manufacturing. The use of LCM is both topical and pressing given the compelling need for sustainable mining ·(OH)2 and KAl2(AlSi3O)(OH)3 have decreased, indicating that the kaolinite, muscovite, and calcite have reacted with the FC. These outcomes match the XRD outcomes.According to ns of CG . CompariSEM is used to describe the shape of the MCG in addition to its composition. At 1000× magnification, as seen in 0, demonstrating an increase in specific surface area. This can be explained in two ways: first, the alteration reduces the size of the CG particles, and second, certain in situ pores are created following the modification process. This has also been supported by other investigations [Based on the results of the aforementioned experiment, it was determined that adding 2 wt.% of FC to the CG significantly improved its dissolving properties and morphology. As a result, the specific surface area of the MCG was further measured by the BET method, as shown in igations .Ermolovich  recommenAlthough the 28 days compressive strength of the BCM2 is higher than the BCM0, the increased value is not noticeable in comparison to the samples at 3 days because the dense hydrate layer formed at an early age will prevent the inner minerals from hydrating, which is consistent with the findings in Ref. .3S and Ca(OH)2 peaks in BCM2 are found to be lower than BCM0 at all ages, indicating a decreased C3S and Ca(OH)2 concentration. According to Ref. [3S hydration results in C-S-H gels and Ca(OH)2, which bind various PC or CG particles together. The formate created during the modification process functions as an accelerator for hydration, which is the cause of the C3S belonging to PC hydrating more quickly than usual. Additionally, the results in The hydrates of the BCM samples were analyzed by XRD in order to determine the hydrates evolution, and the findings are given in  to Ref. , the C3S2 disappears in this reaction after reacting with CG until it reaches around 10 g, as shown by the XRD patterns 2. Si and Al elements in MCG particles are easier to disperse into the solution than CG is in such an alkaline solution due to the FC modification effect, which shrinks the CG particle size and destroys the mineral structure.According to Li et al.  and IranCacciuttolo et al.  noted th(1)The dissolution of CG is obviously influenced by the NaOH content, dissolving duration, and temperature. The dissolution property of CG can be further enhanced by dry chemical modification. The residual of CG reaches a satisfactory value at 2 wt.% FC based on CG.(2)The CG’s structure is destroyed when the FC reacts with the calcite and kaolinite to produce formate, which allows the CG’s particle size to be further reduced when combined with grinding and also increases the CG’s specific surface area.(3)3S and Ca(OH)2 content in BCM, resulting in an increase in C-S-H gels and a denser microstructure of BCM.At 3, 7, and 28 days, BCM prepared with MCG has a compressive strength that is higher than that of the control group. The micro studies demonstrate that the formate accelerated action causes a decrease in C(4)In conclusion, dry chemical modification is a promising strategy that might enhance the activity of CG and enhance the microstructure and compressive strength of BCM made with MCG.In this study, a novel approach, chemical modification, was applied to activate the gangue, and chemically modified CG was used as a basic material for the production of cement backfill paste. To better understand the properties of MCG, the dissolution property of MCG and hydration characteristics of MCG-based backfill pastes were comprehensively investigated in this paper. The takeaways from the study are as follow:The study also has several limitations. First, this present study only focused on the early-age performance of BCM, and did not pay more attention to the long-term performance of BCM. Second, the impact of BCM on Sustainable Development Goals (SDGs) should be discussed further.Despite these limitations, the study has important implications to theory and practice. First, the study enriches the theory of how to improve CG’s reactivity. Second, this work provides a unique method of activating CG, and then makes a comprehensive study on the compressive strength and microstructure of BCM made from activated CG.


Bamboo is a natural vascular bundle (VB) reinforced composite material used in more than 10 fields such as construction and furniture. The nodes in bamboo are crucial to its mechanical properties, but understanding of its performance is limited by lack of knowledge about the three-dimensional (3D) structure of the node. This work aimed to non-destructively identify the multi-dimensional characteristics of the VB in a bamboo branched node (BN) using X-ray microtomography (µCT). The VB was segmented from the BN using deep learning combined with the Watershed algorithm. The 3D model reconstruction and characterization of the VB were also conducted. It was found that the structure of VBs showed significant changes along the height of the BN. The VBs formed a complex 3D structure, VBs of the culm are connected with those of the branch, and the connectivity of the conducting tissue and fibers was 88.91% and 99.95%, respectively. The conducting tissue and the fibers had similar shapes but varying thicknesses, which enabled VBs to perform both water transport and mechanical support functions. The volumes fraction of parenchyma, fibers, and conducting tissue in the BN were 61.3%, 35.3%, and 3.4%, respectively, but the tissue proportion of the different heights of the BN varied from each other. The nodal ridge was a mechanical weak point of the BN, with a maximum fibers proportion of 43.8%. This study contributes to understanding the relationship of VBs between the branch and the culm. It provides a structural perspective for understanding the mechanical properties of BN and a theoretical basis for optimizing bamboo utilization efficiency. NotablyThe structure of bamboo node has a significant structural difference from the internode , althrouX-ray microtomography (µCT) is an ideal non-destructive testing equipment for studying the VB in a BN because of its high spatial resolution and intuitive results . It can Chimonobambusa tumidissinoda Hsueh & T. P. Yi ex Ohrnberger bamboo in a fast, non-destructive, and accurate manner using high-resolution µCT. The study further aimed to reconstruct a 3D model of the conducting tissue and fibers of the BN, explore the structural relationship between the culm and the branch, and discuss the relationship between structure and performance of the BN. This study contributes to the existing understanding of the structure of the bamboo BN.This study aimed to obtain the VB structure in a BN of 22.1C. tumidissinoda bamboos . The parameter of µCT scanning were closely correlated with properties such as the size and density of the samples. The imaging parameters for the sample used in the analysis were: an X-ray source voltage of 70 kV, tube current of 130 µA, power of 2.04 W, rotation step of 0.1°, and exposure time of 108 ms, with each pixel representing a linear resolution of 7.5 μm. There were 2197 projections acquired during the 5 h 20 min. They were exported in TIFF format to allow further analyses.2.3The projection images were reconstructed using a noniterative Filtered Backprojection algorithm in the NRecon software. A sequence of slices was acquired and exported as a stack of TIFF images, obtaining 1293 slices with serial numbers 0-1292 . The conµCT images were segmented using the deep learning U-Net model and manual method in the Dragonfly software , besides the segmentation done using the Watershed algorithm in the Avizo software . Automatic and manual methods were used to segment the µCT images as follows:(1) Fibers ((2) The segmentation results of (1) were manually checked.(3) The watershed method was applied to segment the BN from others in the µCT images. The branches in the slices above slice722 of the BN were not marked because of the culm separation. Then, two pixels of the segmentation of the BN were eroded to remove its cortex.(4) The conducting tissue in the result of (2) was dilated to ensure no pores between the fibers and the conducting tissue.(5) Parenchyma was calculated by subtracting fibers in the result of (2) and conducting tissue in the result of (4) from the BN in the result of (3).(6) The sum of pixel intersections by each two of the fibers and the conducting tissue in the result of (2) and the parenchyma in the result of (5) were removed.(7) The fibers, conducting tissue, and parenchyma in the result of (6) were used as the initial seed spot to perform watershed segmentation  designated on each slice . The significant analysis of the variance of the AVB’s size was subjected to Duncan’s test using the IBM SPSS Statistics 19 software program. The number of VBs was counted on slices 0, 50, 110, 300, 385, 600, 872, and 1292 in the ImageJ software. The area of the BN’s cross-section was measured using the AVIZO software. The frequency of the VB was the number of VBs to the area of the BN’s cross-section. The AVIZO software was also used to obtain the proportion, area, and volume of each type of tissue in the BN. These data were analyzed statistically and plotted using Origin 2018.The size of axial vascular bundle (AVBs) was measured by assessing the length and width of AVBs located within the cross-shaped marquees (2.94×30.52 mm33.13.1.1C. tumidissinoda BN were shown in The morphology features of the The morphological variations of the VB observed in the longitudinal section of the BN can be attributed to its transforming orientation and size . Slices C. tumidissinoda. The shape of the VB changed significantly and differed from the typical VB types, including the metaxylem vessels, phloem with sieve tubes, and protoxylem (In the same line, the boundary of each tissue in the cross-section of the BN was clear, allowing the distinct observation of parenchyma, fibers, and conducting tissue. This finding suggested that µCT could achieve good imaging results of BN in 3.1.2The anatomical features at different heights in the BN was shown in 3.23.2.1The size and quantity of AVBs at different height were quantitatively analyzed due to the structural changes of VBs along the BN height are obvious Table 1.The number and frequency of VBs in the slice of the BN varied with height Table 2.The frequency of the VB of the branch was significantly higher than that of the culm, confirming that the branching VBs were small and dense. The frequency of VBs in the culm decreased from the bottom of the BN to the nodal ridge, then increased towards the top of the BN. The frequency pattern of VBs was similar to that of the unbranched bamboo node , with th3.2.2C. tumidissinoda were 61.3%, 35.3%, and 3.4%, respectively (An advantage of µCT scanning is its ability to analyze the 3D interior tissue proportions, enabling the acquisition of more representative volume data for tissues (ectively . The abuectively . Howeverectively , which d3.33.3.1The anatomical characteristics showed the 2D information of the BN internal structure, which lacked the spatial structure and the continuous size variation related to the number and angle of the BN slices. A morphometrical study of the conducting tissue in a BN is instrumental in understanding its 3D features. Thickness is an important morphological index calculated as the diameter of a hypothetical sphere that fits within each boundary point using the Dragonfly software , where rThe thickness of the conducting tissue in the BN was shown in The 3D thickness model of the conducting tissue achieved a good observation of its morphological variation at different heights but did not elaborate on the relationship between the culm and branch. Image labeling provided valuable and advanced 3D insights into the intricate conducting tissue of the BN, distinguishing the volume of units by different colors , connect3.3.2The thickness of the conducting tissue and fibers in the VB of the bamboo node were inversely correlated . The fibThe maximum thickness of fibers in the BN was 591.88 μm, which was greater than that of the conducting tissue. Here, the fibers were more dispersed while the conducting tissue was more concentrated. . The ranImage labeling provided valuable 3D insights into the complex fibers of the BN, allowing for the differentiation of volume units through the use of distinct colors (4This study employed µCT scanning and 3D reconstruction techniques to observe and analyze the anatomical structure of branched bamboo. The morphology, quantity, frequency, size, and tissue proportion of the VB in a BN were affected by its branch, which caused the gradient structure of bamboo. The 3D visualization of the fibers and conducting tissue was successfully realized, providing real evidence of the structure between the culm and the branch of the BN. Fibers and conducting tissue had similar morphology, yet exhibited distinct variations in thickness patterns, allowing VBs to perform the dual functions of water transport and mechanical support simultaneously. The 3D structure of the VB in the BN provided a new perspective for understanding the performance of the bamboo node, nodal ridge was a weak point in the mechanical properties of BN.The original contributions presented in the study are included in the article/SL: Software, Writing – original draft. QY: Software, Visualization, Methodology, Writing – original draft. YW: Writing – review & editing. LS: Formal Analysis, Software, Visualization, Writing – review & editing. SY: Conceptualization, Methodology, Validation, Writing – review & editing. XL: Formal Analysis, Investigation, Writing – review & editing. QM: Data curation, Resources, Writing – review & editing. ZC: Software, Writing – original draft.


The starting points for the presented analysis were the results of the experimental measurements of the effective thermal conductivity. The measurements were performed for samples of a medium in the form of flat packed beds of bars with three different arrangements: staggered, in-line, and crossed and four bar diameters: 10, 20, 30, and 40 mm. Next, a mathematical model was developed, thanks to which the values of the cth coefficient were calculated for the analyzed cases. This approach consists in analyzing thermal resistances in the medium model, which is defined with an elementary cell. It was established that the value of the cth coefficient in the temperature range of 50–600 °C changes within the range of 50–175 W/(m2·K), and it decreases with an increase in the bar diameter. The final effect of the present study was to develop generalized approximation equations describing changes in thermal contact conductance in the heated bar bundle simultaneously in the temperature and bar diameter function.The paper presents investigations devoted to the analysis of the thermal contact conduction in a bundle of round steel bars. The phenomenon can be expressed quantitatively with the use of thermal contact conductance ( Heat transfer phenomena in low-porosity granular media have been the focus of many scientific and engineering investigations ,4,5,6,7.bnl) and diameter (bnd). The bnl dimension is usually bigger than the diameter bnd by one order of magnitude. This disproportion means that the speed of temperature changes during the bundle heating and cooling are governed by the thermal processes, which take place in radial direction. In this plane, this charge is characterized by discontinuity of the solid skeleton. For this reason, the basic thermal property of a bundle is the effective thermal conductivity (efk). Knowledge of the value of the efk coefficient is indispensable to efficiently control such heat treatment of a charge. Model calculations are one method of determining the value of efk. In the literature on heat transfer in porous media, there are a number of models that are characterized by different levels of complexity [sk), gas (gk), and medium porosity (φ) [cth, the unit of which is W/(m2·K). The issue of thermal contact conduction is still a current and actively researched topic. Several significant results in this field from recent years can be found in the works of [cth coefficient for bundles of round bars made of low-carbon steel.From the macroscopic point of view, the geometry of a bundle can be described with two dimensions: length  ,20. Moresity (φ) ,22. As hsity (φ) . But in works of ,25,26,27cth coefficient, an original research methodology was used, which is based on the analysis of stationary heat transfer in flat, packed beds of steel bars. The starting points for the analyzed problem were the measurements of the effective thermal conductivity performed on a custom laboratory stand. This stand operates on the principle of a guarded hot-plate apparatus in a one-sided mode described in the ASTM standards [In order to determine the value of the tandards ,29. Its q) between the lower and upper surfaces of the specimen. Once a stable condition is achieved, the temperatures at the lower surface (lot) and the upper surface (upt) are recorded. In a manner akin to the characterization of thermal conductivity for solid materials (sk), the effective thermal conductivity is established as [spl) is the dimension of the sample in the direction of heat flow, denoted as is influenced by factors such as the diameter of the bar, the number of layers in the sample, and their arrangement.The measurement method consists of applying a stationary, one-dimensional heat flux keThe specimens under examination were positioned at the bottom of a rectangular steel retort with internal dimensions at the base measuring 400 mm × 400 mm. A primary heater with the same transverse dimensions of 400 mm × 400 mm was situated beneath the retort. The heat emitted by the primary heater was entirely transmitted to the sample, ensured by the operation of side- and bottom-guarded heaters. The power of the primary heater could be manually adjusted using an autotransformer, providing control over the measurement temperature. Additionally, a specialized control system automatically regulated the power of the guarded heaters.Temperature measurements on the lower and upper surfaces were carried out at five opposing locations, using 0.5 mm K-type sheathed thermocouples TP-201 , which wq) within the sample was calculated as the ratio of the heat flux rate (Q) emitted by the primary heater to its surface area (htA). The value of Q was considered equal to the current power (cuP) supplied to this heater. cuP was measured using a 3-phase power network meter N14 [cuP, ranging from 200 to 3200 W. This range of power settings allowed for the determination of temperature variations in the coefficient efk. For a more comprehensive understanding of the testing setup and measurement procedure, additional information can be found in the paper written by [The heat flux  and three arrangements  shown in For each sample, experiments were made for the temperature range of 50–600 °C. As can be seen, samples with individual types of arrangement differ in geometrical conditions of contact between adjacent bars. This differentiation of course affects the intensity of thermal contact conduction phenomena. Therefore, comparison of the results obtained for various sample types provides information on the problem analyzed in the study.efk measurements are presented in efδk) was estimated from an error propagation equation [efδk is marked in the graphs by error bars. Each of the graphs presents the results obtained for the three samples (with different arrangement) made of bars with the same diameter. Therefore, comparison of the results presented in one diagram reveals the effect of sample arrangement on the value of efk. Except for the samples made of bars with diameter of 10 mm, the results obtained for other cases are unequivocal. The greatest value of efk coefficient was observed for staggered (ST) samples, whereas the lowest value was found for the crossed (CR) arrangement. In the latter type, the bars from individual layers are in contact along the whole length, with one bar in contact with two bars from another layer. In the CR samples, due to the crossing of the bars, the contact occurs on many-times smaller, discrete surfaces. The intermediate values of the effective conductivity were obtained for the in-line samples (IL), where bars were in contact along the whole length. However, in this case, each bar from one layer is in contact with only one bar from the next layer. These results demonstrate that contact conduction, with its intensity in granular materials depending on the contact surface area between the adjacent particles, plays a substantial role in the complex heat flow that occurs in bar bundles.The results of the equation , and itsequation . The parefk coefficient.The lack of clear differentiation between individual arrangements in the case of the samples made of 10 mm bars results from the fact that these bars were substantially less rectilinear. This defect caused the bars in staggered and in-line beds to be in contact not along the whole length but only in insignificant sections. Consequently, the arrangement of these bars did not have a significant effect on thermal contact conduction and on the value of efk coefficient are in the range of 1.5–6.9 W/(m·K). The observed increase in efk with temperature for all the samples has a linear character. For this reason, the temperature changes in this parameter for each case were approximated with the linear relationships:The values of the A0 and A1 coefficients from Equation (2) obtained for individual samples are presented in R2, which is also presented in R2 close to one confirm a good match.The values of cth. For this purpose, the special mathematical model of complex heat flow in the bar bed was used. It is assumed that in the analyzed system, heat is transferred by conduction in the section of individual bars, conduction in gas, thermal radiation between the surfaces of bars, and contact conduction. Due to small dimensions of the voids, free convection can be omitted [The equations determined for individual samples described by dependence (2) make it possible to calculate thermal contact conductance  omitted . The sta omitted ,22,39. Tcll) in cls) in The analysis of heat transfer mechanisms which take place in the defined unit cell is based on the thermal resistance concept. It is assumed that in these cells, one-dimensional heat transfer occurs in the vertical direction Rto=ltoR resistance, which is the inverse of thermal contact conductance cth. After several rearrangements, the following dependence was obtained:Using Equations (3)–(5), it is possible to calculate the brR and gsR has been described in the work [brk and gas gsk, which fills the voids. The formulated model assumes that the values of the enumerated coefficients change in the temperature function, which is shown by the following equations:The method of calculating the resistances the work . These rEquation (7) concerns the thermal conductivity of low-carbon steel with 0.2% carbon content. Bars used during the measurements of the effective thermal conductivity were made of this grade of steel (S235JRH). Equation (8) describes the changes in the thermal conductivity of air. Both equations were determined through approximation of the tabular data available in the literature ,43.rdR from Equation (6) is described by the following formula [cσ is the Stefan–Boltzmann constant, mT is mean absolute temperature of the considered medium, and clX is radiation exchange coefficient. This parameter was calculated with the use of the following relations [Radiation resistance  formula :(9)Rrd=Xelations :(10)Xcl=clX coefficient, it is necessary to take into account temperature changes in bar emissivity (ε), which is described by the dependence determined by means of experimental investigations, (Equation (12)) [Equation (10) refers to the medium (bar bed) with staggered arrangement, while Equation (11) refers to the beds with in-line and crossed arrangements. When calculating the on (12)) :(12)ε(t)cth of the analyzed bar beds are presented in 2·K). It can be observed for all the considered cases that the maximum value of the cth coefficient is obtained at a temperature of around 400 °C. At this stage of the investigations, it is not possible to explain this tendency unequivocally due to the complexity of the contact conduction phenomenon. This results from the fact that the value of the cth parameter is a function of many different parameters, for example, surface microhardness, Young’s modulus, Poisson ratio, surface roughness, thermal conductivity of bars which are in contact, or mechanical pressure [cth value. This problem will be subject of further investigations by the authors.The modelled values of the thermal contact conductance pressure ,46,47,48For further analysis, the obtained results were approximated with regression functions in the form of a second-degree polynomial:B0, B1, and B2 coefficients from Equation (13) obtained for individual samples are presented in R2 coefficient, which confirm a good fit of the function to the approximated results.The values of the cth coefficient were calculated. These results are shown in cth.Based on the determined regression equations, for each sample with the analyzed temperature range, the minimum, mean, and maximum values of the ct-meanh values obtained for individual samples, the influence of the bar diameter on the intensity of contact conductance was analyzed. As can be seen in ct-meanh. Using these values, we introduced three parameters, which are defined with the following equations:Using the The values of these parameters are collated in cth values. Using these values, the following parameters were defined:A similar procedure was used in relation to the sample arrangement. The crossed samples are characterized by the lowest cth coefficient value ranges from 16% (40 mm bars) to 32% (20 mm bars). Similarly, as in the previous situation, for the 10 mm bars, this increase was only 6%.The values of these parameters are presented in B0, B1, and B2 coefficients from B0 and B2 parameters can be described with linear equations in the following form (where diameter brd is expressed in mm):Using the B1 coefficients in the bar diameter function change insignificantly; therefore, for each bar arrangement, a constant, averaged value of B1 was adopted. Using the data from The By substituting the Expressions (19)–(27) into Equation (13), we obtained generalized approximation equations describing changes in the thermal contact conductance simultaneously in the temperature and bar diameter function:cth parameter. Formula (6) allowed for the calculation of the cth coefficient based on the results of the experimental studies (measurements of the efk coefficient). In this case, the values of efk were approximated using Equation (2) for the cth parameter calculations. This approach resulted in the outcomes presented in cth coefficient as a function of temperature and bar diameter. Equation (6) did not provide this capability; it was only used as an auxiliary tool to derive Equations (28)–(30).This may raise the question of why different equations, Equations (6) and (28)–(30), were used to calculate the cth calculations obtained with the use of Equations (28)–(30) are shown in ctδh parameter, which was defined with the following dependence:ct-mh modelled values of the thermal contact conductance and ct-aph modelled the thermal contact conductance obtained on the basis of approximation Equations (28)–(30). The maximum values of the ctδh parameter and the ones which were averaged in relation to temperature are presented in The results of the ct-maxh and ct-meanδh equal to 36.1% and 27.3%, respectively, were obtained for the 20 mm bars with a crossed arrangement. For other calculation cases, the values of both parameters did not exceed 20%. When analyzing data from ct-meanδh values for the staggered case for further bar diameters equal 6.5%, 1.9%, 3.5%, and 2.5%. This indicates that the values of the cth coefficient obtained with the use of the approximation Equation (28) are relatively compatible with the results of the precise calculations .This juxtaposition shows that the obtained discrepancies of the results for individual cases are diverse. The highest values of To summarize the conducted research, it was decided to clarify two issues relating directly to industrial practice. The first is the potential industrial applications of various bar arrangements. To address this issue, a photograph of a 10 mm bar bundle was utilized, as shown in The second issue is which thermal treatments are to be applied according to the temperatures selected in the study. The most common heat treatment for steel bars is recrystallization annealing, typically applied after prior plastic processing. The objective of this operation is to improve the plastic properties of the steel. It is carried out below the austenite transformation temperature (723 °C) but above the recrystallization temperature. For steel, depending on its chemical composition, this temperature range is from 400 °C to 700 °C. Therefore, the process of heating the bundle of bars proceeds from room temperature to around 700 °C. Below approximately 500 °C, the key heat exchange process, in terms of intensity, is conductive heat transfer. However, as previously demonstrated by the authors in their earlier publications ,38,41,44cth for a bed of steel bars. It was determined that depending on factors such as temperature, diameter, and arrangement of the bars, the values of the cth parameter are within the range from 50 to 173 W/(m2·K). Next, thanks to the approximation of the results of the model calculations for each bar arrangement, we derived generalized approximation equations which enabled the calculation of the value of the cth coefficient for the packed bar bundles simultaneously in the temperature and bar diameter function. The values of the cth coefficient obtained with the use of this equation for a bar bed with a staggered arrangement (which is how bundles are packed during heat treatment) depending on the bar diameter, differ from the results of the model calculations by 1.9 to 6.5%. Taking into account the complexity of the analysis issue, the level of discrepancy of the results can be regarded as satisfactory. In connection with this, the derived equation can be used to develop a universal model of the effective thermal conductivity of round bar bundles with arbitrary porosity. Developing such a model will be the next stage of work by the authors in the area of heating bundles of steel bars. Upon its validation, such a model will be a valuable computational tool for the optimization of heat treatment processes.Using the results of the experimental investigations and the model of complex heat transfer based on the analysis of thermal resistances, we determined the values of the thermal contact conductance


Hot- and cold-applied joint sealants are materials commonly used for the surface repairs of the upper layers of asphalt or concrete road surfaces. Our investigations covered six hot-applied joint sealants, classified as the high-extension type N1 (elastic) or low-extension type N2 , in accordance with the standard EN 14188-1; the sealants were obtained commercially from four European manufacturers. The present paper focuses on the characterization of the consistency of the joint sealants, the bituminous binders that contain them, and the characterization of their insoluble components. Additional testing methods included an FTIR analysis of the sealants and the extracted binders, as well as SEM, EDS, and sieving analyses of the insoluble material. Joint sealants are complex formulations and include a broad range of base asphalt binders and other components. Their compositions may vary widely, while still fulfilling the performance specifications. Through the extraction of the solvents and the separation of the crack sealants, it was found that radically different compositions of crack sealants resulted in the comparatively similar performance of the tested material. The EDS and FTIR analysis methods provided insights into the composition of the crack sealants and the types of mineral materials used. Maintaining the integrity of the upper layers of road structures ensures their longer life, as well as travel comfort and safety. Preventing the degradation of road construction requires the immediate and permanent maintenance of discontinuities, which occur during pavement service . Hot- anFlexible (high-extension)—type N1;Normal (low-extension)—type N2;High-extension and fuel-resistant—type F1;Low-extension and fuel-resistant—type F2.The selection of the joint sealant type, in terms of its viscoelastic properties and resistance to fuel, as well as the method of application, should result from the role and function that it will perform during the service life of the road surface. As construction products, they must meet the requirements of the applicable standards. In Poland, until March 2005, the composition of joint sealants was strictly regulated, and only products with a defined composition in accordance with the industry standard BN-74/6771-04 were permitted. This composition could include a 45–50% content of D100 road bitumen, a 50-55% content of lime filler, and a 0–5% content of mineral wool. Additionally, the use of additives, such as synthetic resins, to refine the properties of the asphalt binder was permitted. In 2004, the European Committee for Standardization, CEN, introduced new standards for hot-applied joint sealants—EN 14188-1 [Countries such as Canada and the United States use the ASTM  standardIn pavement engineering, various technological solutions are used in the field of asphalt modification, and the use of additives for mineral and asphalt mixtures depends on their purpose in the road surface construction, the environmental conditions, and the pro-ecological requirements ,8,9,10. One of the basic parameters for joint sealants that must be ensured is good adhesion to various types of surfaces . Cao E. Depending on the requirements and purpose, it is possible to regulate the properties of a joint sealant by changing its chemical composition and the proportion of its components—the binders, fillers, additives, and modifiers of the binders ,14,15,16The results of research on the effects of different fillers on the heat resistance, elasticity, flexibility, and performance of polymer-modified mastics at low temperatures have been highlighted by Gnatenko et al. . To reduMichta et al. conducted investigations  on the oAs shown above, joint sealants are typically complex formulations and, given the broad range of base asphalt binders, modifiers, fillers, and other non-soluble additives, their composition may vary widely while still fulfilling the performance specifications. In this study, a forensic-like investigation was carried out on different hot-applied joint sealants to characterize their basic properties and composition.The conducted study showed that the investigated joint sealants were characterized by highly varying contents of soluble asphalt binder, mineral filler, and other components, e.g., crumb rubber. It was found that distinctly different compositions of the crack sealants could result in comparatively similar performances of the tested material given different characteristics of the constituent materials. The use of EDX spectroscopy and Fourier transform infrared spectroscopy (FTIR) methods allowed for the identification of the chemical composition of joint sealants and their individual soluble and non-soluble components.This work utilized physical testing, component chemistry, and functional group analysis to study the sealants. The investigation utilized an expanded scope of tests and identification methods to analyze the joint sealants. The solvent extraction method was applied to study the properties of both the joint sealants and the bituminous binders that contain them, and the EDS and FTIR methods were used to characterize their components, allowing for the comparison of different formulations in terms of their compositions. Such a combined use of different identification methods is not often seen in the evaluation of joint sealant materials. The presented results may provide a basis for future research on the performances of different joint sealant formulations. Investigations into different commercially available joint sealants may also serve a purpose in obtaining economically and ecologically favorable solutions in this regard, e.g., the utilization of waste rubber materials and fine aggregates.The investigations considered hot-applied joint sealants that were classified in accordance with the standard EN 14188-1  as the eAccording to the technical specifications of the selected products, they are designed for filling expansion joints and joints in all kinds of road surfaces. Some of the characteristics of the joint sealants required in , such asThe manufacturers of the JS1 and JS3 sealants have indicated different bonding strengths and cohesion test methods to those indicated in the standard for N1-type sealants; thus, only the requirements for N2 sealants for higher test temperatures were used.The manufacturer of sealant JS6 declared compliance with the requirements of the EN 12,593 standard with regard to the Fraass breaking point by providing a value of ≤−30 °C. This parameter is not required according to EN 14188-1, but it is still valuable for the assessment of the elasticity of the tested material at low temperature.The investigation focused on the consistency characteristics of the joint sealants and the properties of their constituents and did not evaluate the properties related to the adhesion of sealants to various types of surfaces; such an evaluation requires a separate group of tests using primers.◦The determination of the soluble binder content (EN 12697-1);◦The recovery of soluble bitumen with the use of a rotary evaporator (EN 12697-3+A1).The solvent extraction of the investigated joint sealant with the use of tetrachloroethylene as a solvent:◦Needle penetration at 25 °C (EN 1426);◦Cone penetration at 25 °C —only joint sealants;◦Softening point, ring, and ball (EN 1427);◦Fraass breaking point (EN 12593);◦Elastic recovery at 25 °C (EN 13398).Basic properties of the joint sealant and soluble asphalt binder:Fourier transform infrared spectroscopy (FTIR) using the attenuated total reflectance (ATR-FTIR) method.The testing methodologies included:The vacuum evaporator distillation procedure suitable for the solvent was used in accordance with EN 12697-3+A1 .The Thermo-Scientific Nicolet iS 5 FTIR Spectrometer and the PIKE Technologies GladiATR attenuated total reflectance accessory with a diamond window was used for the Fourier transform infrared analysis. The FEI Quanta Feg 250 SEM scanning electron microscope was used for elemental analysis.◦Mineral filler grading using the standard 0.063 mm sieve (EN-933-1)—mass of fines passing through the 0.063 mm sieve;◦Mineral and rubber dust using a standard sieve 0.063 mm (EN-933-1) and filter (sieve) 0.19 mm—mass of dust passing through the 0.19 mm filter (sieve);◦Fine/rubber granule grading using filter (sieve) 0.19 mm—mass of material retained.Sieving analysis of non-soluble components:Evaluation of chemical composition of non-soluble components with the use of EDX spectroscopy (Quanta Feg 250 SEM and EDS spectrum).For the non-soluble components of the joint sealants, the testing methodology included:Due to the type of material and fine grain size of the filler, sieving was performed for a sealant diluted with a solvent using only a standard sieve of 0.063 and a filter (sieve) of 0.19 mm.The composition of the investigated joint sealants (JS1–JS6) was determined on the basis of extractions performed with the use of tetrachloroethylene as a solvent . In addition to their main component, which was the asphalt binder, mineral filler and rubber particles were found. The solvent extraction results are illustrated in The current standard EN 14188-1 does not impose the percentages of the components of hot-applied joint sealants. The investigated joint sealants are therefore characterized by the highly varied content of the asphalt binder and other components .The content of soluble asphalt binder in the investigated joint sealants ranged from 49.8 to 72.8%. In the sealants JS1, JS3, JS4, and JS5, it was close to 70%. In five joint sealants (JS1–JS5), the occurrence of rubber particles with a grain size above 0.19 mm with different content percentages (6.9–14.8%) was found. The identified crumb rubber contents were similar to those investigated by Gnatenko et al.  and GongIn the JS1–JS4 sealants, combined mineral and rubber dust particles , which were difficult to separate into mineral and rubber parts, were also screened (3.9–12.4%).The content of mineral filler passing the 0.063 mm sieve in sealants JS1–JS5 ranged from 10.6 to 21.7%. The JS6 joint sealant consisted of an asphalt binder and a mineral filler that passed through the 0.063 mm sieve (50.2/49.8%).A visual evaluation of the components separated from the joint sealants  indicateIn order to check the homogeneity of the investigated material, a minimum of four measurement points were selected in the places of the occurrence of fragments differing in size, shape, or color in the macroscopic assessment. EDX (energy-dispersive X-ray) spectroscopy was used to validate the composition of the mineral fillers. The scanning electron microscope images of the mineral fillers extracted from the joint sealants are shown in The chemical composition of the mineral fillers extracted from sealants JS1–JS6 is given in The analysis of the chemical composition , Table 3In the mineral fillers derived from the joint sealants JS1, JS4, and JS5, the dominant share of calcium was found at all the measuring points, indicating a use of limestone filler. In the material obtained from the J3 and JS6 sealants, a similar chemical composition was identified in some of the measuring points . For the JS2 joint sealant and other measuring points from the JS3 and JS6 sealants, silicon had the highest percentage in the investigated material, which indicates the use of mineral fillers of other origins in the production of joint sealants.The scanning electron microscope images of the rubber powder/crumb extracted fromthe JS1–JS2 sealants are shown in The chemical composition of the fines/rubber granules extracted from sealants JS1–JS5 is given in In rubber from used car tires, there can be many components, such as natural and synthetic rubber, aromatic oils, fillers, sulfur, and other chemical additives . The varRubber waste can be characterized by various components and chemical additives. In order to identify the degree of variation in their composition and grinding method , 6 to 15 measurement points were selected. They were designated in the places of the occurrence of fragments differing in size, shape, or color in the macroscopic assessment. Selected fragments of the rubber particles are shown at ×500  or ×2.000 (JS2) magnification.The rubber particles identified in the JS2 joint sealant b have a Due to the difficulties in fully separating mineral fillers from rubber, elements of mineral origin might have also appeared in the investigated material. The presence of elements of mineral origin, such as calcium, magnesium, and silicon, was found . In addiThe evaluations of the penetration at 25 °C, the softening point, the Fraass breaking point, and the elastic recovery were performed to measure the effects of different types and compositions of joint sealants on their and the asphalt binders’ classical properties. The determined values of the softening point  correspoA comparison with the standard requirements  for coneThe highest value of the Fraass breaking point characterized the JS1 and JS4 sealants. For the other materials, this parameter was lower than −25 °C. The Fraass breaking point test is not required according to EN 14188-1, but it is important for the assessment of the elasticity of the tested joint sealant at a low temperature.The analysis of the results in The results of the elastic recovery test at 25 °C in the case of sealants JS1 and JS3–JS6 indicated a very high rate of elastomeric modification similar to that seen in the highly modified bitumens produced in Poland according to the national annex of the PN-EN 14,023 standard; these are characterized by a high content of SBS polymer in an amount equaling about 7–7.5% m/m. The high elasticity of the binder ensures the proper operation of the elastic joint sealants, allowing for the transmission of the significant deformations and strains caused by both vehicle traffic and climatic factors. The JS2 sample failed before the end of the test but showed an almost immediate return to its original shape.The cone penetration tests indicated significant variability in the consistency of the joint sealants (25.6 to 75.4 × 0.1 mm). This was also evident in the scope of the needle penetration and the diverse properties of the asphalt (63 to 136.3 × 0.1 mm). The softest asphalt binders were used for the N1 type joint sealants , but this did not significantly affect the properties of the joint sealants. The properties of the asphalt binders were, to varying degrees, transferred to the characteristics of the sealants .The penetration and softening point tests indicated that the JS2 sealant was the hardest in consistency, while JS6 was the most susceptible to high temperatures. In addition, the JS2 sealant did not meet the requirements of the standard  nor the The lowest softening point was determined for the JS6 joint sealant, which uses an asphalt binder with similarly low characteristics. At the same time, this sealant comprised the largest mass share of mineral filler in its composition (approx. 50%).Both the joint sealants and the extracted bitumens had high average elastic recovery values that ranged from 91 to 98% for the joint sealants and 96 to 100% for the binders.The FTIR spectra of the evaluated joint sealants and the extracted soluble contents of the asphalt binders are presented in −1 to 500 cm−1 absorption bands of the overlayed spectra of the joint sealants.−1 and 712 cm−1 wavenumber regions were observed, accompanied by the rise of the absorption in the 1500–1300 cm−1 wavenumber region. These absorption bands could be attributed to the presence of calcium carbonate , which is characterized by a strong and broad 1410 cm−1 peak (asymmetric C-O stretching) and two smaller peaks at 873 cm−1 (out-of-plane vibration) and 712 cm−1 (in-plane vibration) [−1 and 500 cm−1 wavenumber regions, which were possibly associated with the presence of SiO2 [The infrared spectra of the investigated joint sealants varied significantly and significantly differed from the typical FTIR spectra of bitumen. These differences were most likely due to the presence of fine mineral aggregates and rubber particles and possibly to other components of the joint sealants. In the infrared spectra of joint sealants JS1, JS3, JS4, JS5, and JS6, prominent absorption peaks in the 873 cmbration) ,32. The  of SiO2 ,34.2 could not be easily established based on the FTIR spectra of the JS3 and JS6 sealants; this is possibly due to the effects of other adjacent absorbance bands . On the other hand, the presence of SiO2 was not confirmed in the EDS analysis of the JS4 sealant; this could potentially be attributed to the point-like nature of the employed method of measurement. The summary and comparison of the chemical analyses performed using the FTIR and EDS methods are provided in These observations are mostly in line with the results of the EDS elemental analysis shown in , which c−1 to 500 cm−1 absorption bands in the FTIR spectra of the soluble asphalt binders extracted from the joint sealants.−1 and 1030 cm−1 wavenumber regions associated with carbonyl and sulfoxide compounds, indicating that they were not exposed to a significant amount of oxidation.All the FTIR spectra of the extracted asphalt binders show low, comparable peak heights in the 1700 cm−1, indicating the presence of butadiene structures; at 990 cm−1 and 910 cm−1, which are characteristic of vinyl groups; and at 699 cm−1, which is characteristic of styrene structures. These responses indicate the presence of styrene–butadiene rubber in the samples of the tested soluble material. Additionally, the asphalt binder extracted from the JS2 and JS5 joint sealants registered prominent peaks at the 1745 cm−1 wavenumber, which is typically seen in bio-oil derivatives  and may correspond to the stretching of the -C=O in ester functional groups.All of the extracted binders exhibited significant peaks at 966 cmThe solvent extraction showed that the investigated joint sealants were characterized by different contents of soluble asphalt binder (49.8 to 72.8%), mineral filler that passed through a 0.063 mm sieve (10.6 to 50.2%), and other components, e.g., crumb rubber.The use of the EDX spectroscopy method indicated significantly varied chemical composition and the origin of the non-soluble components  used in the production of the joint sealants.The tests showed similar properties of the sealants in terms of elastic recovery at 25 °C (91 to 98%), despite the different contents and chemical compositions of their individual components, the results indicated a very high degree of elastomeric modification of the bitumens used in the sealants and/or the effect of rubber modification, regardless of its type .The determined values of the softening point corresponded with the European standard requirements for all investigated hot-applied joint sealants (≥85 °C). The lowest softening points were determined for the joint sealant that used asphalt binders with similarly low characteristics and had the largest mass share of mineral filler in its composition (approx. 50%).The cone penetration tests indicated significant variability in the consistency of the joint sealants (25.6 to 75.4 × 0.1 mm). One of the sealants met neither the requirements of the applicable European standard nor the manufacturer’s declaration for cone penetration (40 to 100 × 0.1 mm).−1, indicating the presence of butadiene structures; at 990 cm−1 and 910 cm−1, which are characteristic of vinyl groups; and at 699 cm−1, which is characteristic of styrene structures.The FTIR spectra of the extracted asphalt binders showed significant peaks at 966 cmThe use of EDX spectroscopy and Fourier transform infrared spectroscopy (FTIR) methods allowed us to perform analyses of the chemical composition of the joint sealants and their individual soluble and non-soluble components for comparative purposes, as well as enabling the determination of their optimal composition.The FTIR method was shown to be able to indicate the presence of calcareous fillers in asphaltic materials; the spectral response of siliceous aggregates was too weak to reliably confirm their presence in the joint sealants, particularly when fine calcareous aggregates were also present.It is possible to regulate the selected properties of the joint sealant by changing the chemical composition and the proportion of its components.Joint sealants are complex formulations and, given a broad range of base asphalt binders, modifiers, fillers, and other non-soluble additives, their composition may vary widely, while still fulfilling the performance specifications.The present study considered the chemical composition and basic performance properties of hot-applied joint sealants and their components. Based on the study, the conclusions were as follows:In the present study, the composition of different crack sealing materials was inferred and juxtaposed with their performance. The investigation utilized an expanded scope of tests and identification methods to analyze the joint sealants, including material extraction and the testing of the properties of the component materials. In the investigation, it was found that EDS and FTIR together with the solvent extraction, and separation provided insights into the composition of the joint sealants and the types of mineral materials used. It was also shown that radically different compositions of the crack sealants could result in a comparatively similar engineered final performance of the tested material.The combined use of these analysis methods could be used in, for example, forensic investigations to evaluate the fine aggregate composition used in asphaltic materials, such as asphalt mixtures and joint sealants. The results will provide a basis for subsequent research to develop an experiment plan to evaluate the effects of the composition of different joint sealants on their functional and durability characteristics, including economic and sustainability considerations.