Pub Date : 2022-07-08DOI: 10.37538/2224-9494-2022-2(33)-20-31
L. Adegova, M. V. Bobrysheva, A. E. Shcherbinina
Introduction. At present, composite materials are widely used in building structures and their components. The relevance of the work is determined by the buckling study of a shell structure made of a carbon fiber reinforced polymer. Despite the available experience in creating geometric models of finite element grids and studying the buckling of shell structures, the task of analyzing the mechanical behavior of shell layers remains insufficiently investigated. Therefore, research into the effects caused by polymer layering variations on a buckling mode appears to be urgent for regulating the layering process at various angle combinations due to a lack of sufficient data.Aim. The study was aimed at identifying a layering pattern, under which maximum and minimum critical forces operate.Materials and methods. The object of the study involves a cylindrical shell with a radius of 300 mm, a height of 600 mm, and a wall thickness of 1.56 mm made of eight variously-oriented carbon fiber layers impregnated with epoxy resin. The design modeling was performed using the finite element method. The cylindrical shell walls were modeled in terms of Laminate type flat elements, taking into account the composite layers. At the lower end, the cylinder was rigidly fixed and 100 kN axial compressive force was applied to the upper end of the cylinder. Using a software package, the variants of buckling modes were obtained for further analysis.Results. The data, describing the buckling of a cylindrical shell, including the critical load coefficient at the first buckling mode were obtained by the finite element method. In addition, the dependence of a critical force on layering patterns was determined. Depending on the critical force value and the buckling mode, the most and least favorable patterns of layering in a package of a composite material were selected.Conclusions. The orientation of layers in a composite material package affects the buckling mode and the value of critical force. An optimal selection of the layer orientation increases the critical force value by 2.25 times based on the information about the conditions of structural loading and fastening.
{"title":"Effects of composite material layering on the buckling mode of a cylindrical shell","authors":"L. Adegova, M. V. Bobrysheva, A. E. Shcherbinina","doi":"10.37538/2224-9494-2022-2(33)-20-31","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-20-31","url":null,"abstract":"Introduction. At present, composite materials are widely used in building structures and their components. The relevance of the work is determined by the buckling study of a shell structure made of a carbon fiber reinforced polymer. Despite the available experience in creating geometric models of finite element grids and studying the buckling of shell structures, the task of analyzing the mechanical behavior of shell layers remains insufficiently investigated. Therefore, research into the effects caused by polymer layering variations on a buckling mode appears to be urgent for regulating the layering process at various angle combinations due to a lack of sufficient data.Aim. The study was aimed at identifying a layering pattern, under which maximum and minimum critical forces operate.Materials and methods. The object of the study involves a cylindrical shell with a radius of 300 mm, a height of 600 mm, and a wall thickness of 1.56 mm made of eight variously-oriented carbon fiber layers impregnated with epoxy resin. The design modeling was performed using the finite element method. The cylindrical shell walls were modeled in terms of Laminate type flat elements, taking into account the composite layers. At the lower end, the cylinder was rigidly fixed and 100 kN axial compressive force was applied to the upper end of the cylinder. Using a software package, the variants of buckling modes were obtained for further analysis.Results. The data, describing the buckling of a cylindrical shell, including the critical load coefficient at the first buckling mode were obtained by the finite element method. In addition, the dependence of a critical force on layering patterns was determined. Depending on the critical force value and the buckling mode, the most and least favorable patterns of layering in a package of a composite material were selected.Conclusions. The orientation of layers in a composite material package affects the buckling mode and the value of critical force. An optimal selection of the layer orientation increases the critical force value by 2.25 times based on the information about the conditions of structural loading and fastening. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121268560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-08DOI: 10.37538/2224-9494-2022-2(33)-32-43
P. Arleninov
Introduction. The main approaches to long-term creep tests of concrete regulated by GOST 24544-2020, valid in the Russian Federation, as well as foreign ISO, ASTM, and EN standards, are analyzed.Aim. In this work, fundamental differences in conducting tests following Russian and foreign standards are determined. These efforts are essential and urgent, since, in order to use test results obtained abroad in Russia, it is necessary to harmonize test methods and initial test parameters (samples, measuring and test equipment, etc.).Materials and methods. The article reviews testing procedures, controlled parameters, and processing of result; part 1 of the article covered the application, testing and measuring equipment, manufacturing process, sample parameters and fittings, and test preparation.Results. ISO, ASTM, and EN are comparable; however, they differ greatly from GOST 24544 in some respects, in particular, regarding the sample parameters and the methods of their installation in the testing equipment.Conclusion. Further harmonization of GOST 24544 with the aforementioned foreign standards is necessary.
{"title":"Comparison of concrete creep test methods as per Russian and foreign normative documents. Part 2. Testing and processing of results","authors":"P. Arleninov","doi":"10.37538/2224-9494-2022-2(33)-32-43","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-32-43","url":null,"abstract":"Introduction. The main approaches to long-term creep tests of concrete regulated by GOST 24544-2020, valid in the Russian Federation, as well as foreign ISO, ASTM, and EN standards, are analyzed.Aim. In this work, fundamental differences in conducting tests following Russian and foreign standards are determined. These efforts are essential and urgent, since, in order to use test results obtained abroad in Russia, it is necessary to harmonize test methods and initial test parameters (samples, measuring and test equipment, etc.).Materials and methods. The article reviews testing procedures, controlled parameters, and processing of result; part 1 of the article covered the application, testing and measuring equipment, manufacturing process, sample parameters and fittings, and test preparation.Results. ISO, ASTM, and EN are comparable; however, they differ greatly from GOST 24544 in some respects, in particular, regarding the sample parameters and the methods of their installation in the testing equipment.Conclusion. Further harmonization of GOST 24544 with the aforementioned foreign standards is necessary. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132085325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-25DOI: 10.37538/2224-9494-2022-2(33)-83-96
S. Zenin
Introduction. A sustainable system of risk management in construction is in great demand for both consumers and suppliers of construction products. As one of the main elements of such a system, probability calculations of loader-bearing structures provide a necessary level of reliability and optimality of construction solutions. At the same time, the transition towards risk-oriented design, including the assessment and management of risks, implies the presence of sufficient statistic data, along with the methods of data collection and probability modeling. This study is focused on the issues concerned with collecting data for probability calculations.Aim. To propose suggestions for improving the national regulatory framework as related to probability calculations of reinforced concrete structures and collecting the necessary data.Materials and methods. The main objectives of the study were to investigate and analyze Russian and foreign experience in the field of risk assessment and management in terms of building structures and facilities based on probability calculations. In order to achieve these objectives, an analysis of existing Russian and international documents was carried out. In the course of the study, national regulatory legal acts and standardization documents including codes of rules and GOSTs were considered. In addition, some national regulatory technical documents, which were not included in the lists of both obligatory and non-obligatory applications, were analyzed, as well as other specialized regulatory technical documents. An analysis of foreign regulatory technical documents was conducted, including those regulating the initial data characteristics to perform probability calculations (loads, materials, and calculation models). In general, the methodology for analyzing regulatory technical documents involved a detailed study of the selected documents, an analysis of their positions concerning the issue under consideration, as well as an assessment of the completeness and sufficiency of the positions of the documents concerning the methods for determining the initial data characteristics for probability calculations of reinforced concrete structures regarding loads, materials and calculation models.Conclusions. On the basis of the conducted analysis, specific subject areas for research works are formulated focusing on the development of probability calculations of reinforced concrete structures. A system of regulatory documents is proposed enabling an optimal risk-oriented design of reinforced concrete structures to be implemented.
{"title":"Analysis of regulatory documents regarding data collection for probability calculations of reinforced concrete structures","authors":"S. Zenin","doi":"10.37538/2224-9494-2022-2(33)-83-96","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-83-96","url":null,"abstract":"Introduction. A sustainable system of risk management in construction is in great demand for both consumers and suppliers of construction products. As one of the main elements of such a system, probability calculations of loader-bearing structures provide a necessary level of reliability and optimality of construction solutions. At the same time, the transition towards risk-oriented design, including the assessment and management of risks, implies the presence of sufficient statistic data, along with the methods of data collection and probability modeling. This study is focused on the issues concerned with collecting data for probability calculations.Aim. To propose suggestions for improving the national regulatory framework as related to probability calculations of reinforced concrete structures and collecting the necessary data.Materials and methods. The main objectives of the study were to investigate and analyze Russian and foreign experience in the field of risk assessment and management in terms of building structures and facilities based on probability calculations. In order to achieve these objectives, an analysis of existing Russian and international documents was carried out. In the course of the study, national regulatory legal acts and standardization documents including codes of rules and GOSTs were considered. In addition, some national regulatory technical documents, which were not included in the lists of both obligatory and non-obligatory applications, were analyzed, as well as other specialized regulatory technical documents. An analysis of foreign regulatory technical documents was conducted, including those regulating the initial data characteristics to perform probability calculations (loads, materials, and calculation models). In general, the methodology for analyzing regulatory technical documents involved a detailed study of the selected documents, an analysis of their positions concerning the issue under consideration, as well as an assessment of the completeness and sufficiency of the positions of the documents concerning the methods for determining the initial data characteristics for probability calculations of reinforced concrete structures regarding loads, materials and calculation models.Conclusions. On the basis of the conducted analysis, specific subject areas for research works are formulated focusing on the development of probability calculations of reinforced concrete structures. A system of regulatory documents is proposed enabling an optimal risk-oriented design of reinforced concrete structures to be implemented. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131373587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-25DOI: 10.37538/2224-9494-2022-2(33)-139-149
T. Mukhamediev, S. Zenin, A. S. Zharkikh
Introduction. The current standards for the design of concrete and reinforced concrete structures provide no methods for calculating the strength of the oblique sections in bending elements of various cross-sectional shape under the action of transverse forces. This prompts the designers to use simplifications in calculation of such elements, which, in some cases, may lead to excessive consumption of transverse reinforcement or the strength underestimation.Aim. The performed study was aimed at assessing the reliability of a new method for calculating the strength of oblique sections in bending reinforced concrete structures with a non-rectangular cross-sectional shape.Materials and methods. The reliability assessment of a new procedure for calculating oblique sections of a various cross-sectional shape was performed by the comparison between the calculated and experimental values of the transverse force received by the oblique section of reinforced concrete elements with various cross-sectional shape. The study considers the oblique bending tests of the samples with an annular, circular, and square cross-sectional shape, as well as T-shaped samples with a crossbar both in a stretched and compressed zone. The reliability assessment was performed using generally accepted methods of statistical analysis.Results. The distributions of ratios of the experimental and calculated values of the destructive transverse force for various-section test samples were obtained to be close to normal ones. According to the results of the reliability assessment, the proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was established to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices.Conclusions. The proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was determined to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices.
{"title":"The reliability assessment of the method for calculating the strength of oblique sections in reinforced concrete elements with various cross-sectional shape","authors":"T. Mukhamediev, S. Zenin, A. S. Zharkikh","doi":"10.37538/2224-9494-2022-2(33)-139-149","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-139-149","url":null,"abstract":"Introduction. The current standards for the design of concrete and reinforced concrete structures provide no methods for calculating the strength of the oblique sections in bending elements of various cross-sectional shape under the action of transverse forces. This prompts the designers to use simplifications in calculation of such elements, which, in some cases, may lead to excessive consumption of transverse reinforcement or the strength underestimation.Aim. The performed study was aimed at assessing the reliability of a new method for calculating the strength of oblique sections in bending reinforced concrete structures with a non-rectangular cross-sectional shape.Materials and methods. The reliability assessment of a new procedure for calculating oblique sections of a various cross-sectional shape was performed by the comparison between the calculated and experimental values of the transverse force received by the oblique section of reinforced concrete elements with various cross-sectional shape. The study considers the oblique bending tests of the samples with an annular, circular, and square cross-sectional shape, as well as T-shaped samples with a crossbar both in a stretched and compressed zone. The reliability assessment was performed using generally accepted methods of statistical analysis.Results. The distributions of ratios of the experimental and calculated values of the destructive transverse force for various-section test samples were obtained to be close to normal ones. According to the results of the reliability assessment, the proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was established to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices.Conclusions. The proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was determined to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122474497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-22DOI: 10.37538/2224-9494-2022-2(33)-161-172
A. Nikitin
Introduction. At present, various approaches to standardization in construction are used that are often in poor agreement. This hinders international cooperation and collaborative planning, design, and construction of facilities. The harmonization of construction standards has been long overdue.Aim. In this work, international standards were monitored and compared with Russian analogs in order to develop an approach to their harmonization.Materials and methods. The European and American standards of the International Organization for Standardization (ISO) were selected for further comparison with the Russian analogs. A random monitoring, analysis, and comparison of ISO standards and Russian regulatory-technical base were carried out for its timely update, the elimination of emerging redundancies and contradictions, and the improvement of the harmonization of Russian and international standards in construction in the scope of ISO/TC 71 “Concrete, reinforced concrete, pre-stressed reinforced concrete.”Results. The analysis of 14 international ISO standards allowed the documents to be classified into three groups for further work and steps toward their possible harmonization with the Russian national standards and toward the development of analogous national standards to be outlined.Conclusions. Based on the monitoring results, it is recommended to classify ISO standards into three groups: 1. ISO standards of lesser relevance to national standardization due to a complete or, in some cases, more comprehensive regulatory base. 2. ISO standards where the standardization parameters differ from Russian standards or where the subject of standardization is reflected in several associated standards. Such standards should be harmonized with international standards. 3. ISO standards having no national analogs. Therefore, it is recommended to harmonize the Russian standards related to the second group and, in the absence of Russian analogs, develop national standards equivalent to those of the third group.
{"title":"Monitoring of international standards in the scope of ISO/TC 71 “Concrete, reinforced concrete, pre-stressed concrete”","authors":"A. Nikitin","doi":"10.37538/2224-9494-2022-2(33)-161-172","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-161-172","url":null,"abstract":"Introduction. At present, various approaches to standardization in construction are used that are often in poor agreement. This hinders international cooperation and collaborative planning, design, and construction of facilities. The harmonization of construction standards has been long overdue.Aim. In this work, international standards were monitored and compared with Russian analogs in order to develop an approach to their harmonization.Materials and methods. The European and American standards of the International Organization for Standardization (ISO) were selected for further comparison with the Russian analogs. A random monitoring, analysis, and comparison of ISO standards and Russian regulatory-technical base were carried out for its timely update, the elimination of emerging redundancies and contradictions, and the improvement of the harmonization of Russian and international standards in construction in the scope of ISO/TC 71 “Concrete, reinforced concrete, pre-stressed reinforced concrete.”Results. The analysis of 14 international ISO standards allowed the documents to be classified into three groups for further work and steps toward their possible harmonization with the Russian national standards and toward the development of analogous national standards to be outlined.Conclusions. Based on the monitoring results, it is recommended to classify ISO standards into three groups: 1. ISO standards of lesser relevance to national standardization due to a complete or, in some cases, more comprehensive regulatory base. 2. ISO standards where the standardization parameters differ from Russian standards or where the subject of standardization is reflected in several associated standards. Such standards should be harmonized with international standards. 3. ISO standards having no national analogs. Therefore, it is recommended to harmonize the Russian standards related to the second group and, in the absence of Russian analogs, develop national standards equivalent to those of the third group. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124738716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.37538/2224-9494-2022-2(33)-97-105
S. I. Ivanov, A. Nevskii, D. Chesnokov
Introduction. The method of determining concrete strength based on steel stud driving into concrete by firing has been used since the 1960s. At present, several institutions promote this method as an alternative to direct nondestructive testing methods (pullout test and shear angles) and propose to introduce it into the current standard GOST 22690-2015. Its availability and low cost compared to those of the existing standard methods are mentioned to substantiate this proposal.Aim. In this work, domestic and foreign studies and normative documents regulating the considered test method are analyzed, and its standardization and the volume of additional research are evaluated.Materials and methods. Theses from the mid-20th century to the present, normative documents (ASTM C803-02, BS 1881-207, DIN EN 14488-2), and instructions (Z-WP-534. Windsor Probe System, Driving method Hilti DX 450-SCT) were reviewed.Results. Significant limitations for the application and the factors having the most profound influence on the accuracy of the method were identified: hardness, type, and fineness of the filler, variation of firing charge power, and indenter parameters (driven stud). These factors have no influence on the control methods recommended by the existing standards. Foreign standards stipulate the application of this test method as an indirect technique, requiring adjustments based on the testing results of standard samples or test cores extracted from structures; however, no data on its accuracy is provided.Conclusion. Given the revealed limitations, it is premature to standardize the method. Further research is recommended. The statement about the significant availability and cheapness of the reviewed method relative to the standard regulated methods is unsubstantiated.
介绍。自20世纪60年代以来，测定混凝土强度的方法是基于钢钉通过燃烧打入混凝土的方法。目前，已有多家机构将该方法作为直接无损检测方法(拉拔试验和剪切角试验)的替代方法进行推广，并建议将其纳入现行标准GOST 22690-2015中。与现有的标准方法相比，它的可用性和低成本证明了这一建议。在本工作中，分析了国内外研究和规范所考虑的测试方法的规范性文件，并对其标准化和额外的研究量进行了评价。材料和方法。论文从20世纪中期到现在，规范性文件(ASTM C803-02, BS 1881-207, DIN EN 14488-2)，和说明(Z-WP-534。综述了温莎探针系统、驱动方法喜利得DX 450-SCT。确定了应用的重大限制和对方法精度影响最深远的因素:填料的硬度、类型和细度、点火功率的变化和压头参数(驱动螺柱)。这些因素对现行标准推荐的控制方法没有影响。国外标准规定该试验方法作为间接技术应用，要求根据从结构中提取的标准样品或试验岩心的试验结果进行调整;然而，没有提供关于其准确性的数据。鉴于所揭示的局限性，现在对该方法进行标准化还为时过早。建议进一步研究。与标准监管方法相比，所审查方法的显著可用性和廉价性的说法是没有根据的。
{"title":"Specific features of determining concrete strength by stud driving method","authors":"S. I. Ivanov, A. Nevskii, D. Chesnokov","doi":"10.37538/2224-9494-2022-2(33)-97-105","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-97-105","url":null,"abstract":"Introduction. The method of determining concrete strength based on steel stud driving into concrete by firing has been used since the 1960s. At present, several institutions promote this method as an alternative to direct nondestructive testing methods (pullout test and shear angles) and propose to introduce it into the current standard GOST 22690-2015. Its availability and low cost compared to those of the existing standard methods are mentioned to substantiate this proposal.Aim. In this work, domestic and foreign studies and normative documents regulating the considered test method are analyzed, and its standardization and the volume of additional research are evaluated.Materials and methods. Theses from the mid-20th century to the present, normative documents (ASTM C803-02, BS 1881-207, DIN EN 14488-2), and instructions (Z-WP-534. Windsor Probe System, Driving method Hilti DX 450-SCT) were reviewed.Results. Significant limitations for the application and the factors having the most profound influence on the accuracy of the method were identified: hardness, type, and fineness of the filler, variation of firing charge power, and indenter parameters (driven stud). These factors have no influence on the control methods recommended by the existing standards. Foreign standards stipulate the application of this test method as an indirect technique, requiring adjustments based on the testing results of standard samples or test cores extracted from structures; however, no data on its accuracy is provided.Conclusion. Given the revealed limitations, it is premature to standardize the method. Further research is recommended. The statement about the significant availability and cheapness of the reviewed method relative to the standard regulated methods is unsubstantiated. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129715188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-19DOI: 10.37538/2224-9494-2022-2(33)-183-193
V. Stepanova, G. Chehniy, I. M. Parshina, S. A. Orekhov, A. I. Kruglov
Introduction. The development of the Arctic Region and oil and gas fields in the North Atlantic Ocean leads to an increase in the production of high-strength concrete structures. Thus, it is becoming increasingly vital to make such low-permeability concretes more freeze-thaw resistant.Aim. To conduct experimental studies for obtaining reliable data required to develop a standardized approach to the normalization of freeze-thaw / frost-salt resistance parameters characterizing high-strength concretes.Materials and methods. The study was performed using concretes of eight compositions (B60–B100 compressive strength grades). The freeze-thaw/frost-salt resistance of high-strength concretes was determined using the third rapid method involving the saturation, freezing, and thawing of samples in a 5 % sodium chloride solution, as well as assessment of freeze-thaw resistance in terms of strength, mass variation, and the dynamic modulus of elasticity. A variety of methods for increasing the water saturation of highstrength concrete were examined in order to expedite the testing process of high-strength concrete for freeze-thaw resistance.Results. The studies into the freeze-thaw/frost-salt resistance of high-strength B60-B100 concretes revealed their high freeze-thaw resistance. Following 37 freeze-thaw cycles, the lower confidence limit for the strength of test samples was higher than that of control samples multiplied by a coefficient of 0.9. The frost-resistance grade of these concretes is above F2 300. No critical decrease in the dynamic modulus of elasticity is observed, which indicates a significant freeze-thaw/frost-salt resistance of all tested highstrength concrete compositions.Conclusions. The freeze-thaw resistance studies of high-strength concretes carried out at NIIZHB named after A.A. Gvozdev yielded experimental data required to subsequently develop a standardized approach to the normalization of freeze-thaw/frost-salt resistance parameters characterizing high-strength concretes.
{"title":"Study into the freeze-thaw/ frost-salt resistance of high-strength B60–B100 concrete","authors":"V. Stepanova, G. Chehniy, I. M. Parshina, S. A. Orekhov, A. I. Kruglov","doi":"10.37538/2224-9494-2022-2(33)-183-193","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-183-193","url":null,"abstract":"Introduction. The development of the Arctic Region and oil and gas fields in the North Atlantic Ocean leads to an increase in the production of high-strength concrete structures. Thus, it is becoming increasingly vital to make such low-permeability concretes more freeze-thaw resistant.Aim. To conduct experimental studies for obtaining reliable data required to develop a standardized approach to the normalization of freeze-thaw / frost-salt resistance parameters characterizing high-strength concretes.Materials and methods. The study was performed using concretes of eight compositions (B60–B100 compressive strength grades). The freeze-thaw/frost-salt resistance of high-strength concretes was determined using the third rapid method involving the saturation, freezing, and thawing of samples in a 5 % sodium chloride solution, as well as assessment of freeze-thaw resistance in terms of strength, mass variation, and the dynamic modulus of elasticity. A variety of methods for increasing the water saturation of highstrength concrete were examined in order to expedite the testing process of high-strength concrete for freeze-thaw resistance.Results. The studies into the freeze-thaw/frost-salt resistance of high-strength B60-B100 concretes revealed their high freeze-thaw resistance. Following 37 freeze-thaw cycles, the lower confidence limit for the strength of test samples was higher than that of control samples multiplied by a coefficient of 0.9. The frost-resistance grade of these concretes is above F2 300. No critical decrease in the dynamic modulus of elasticity is observed, which indicates a significant freeze-thaw/frost-salt resistance of all tested highstrength concrete compositions.Conclusions. The freeze-thaw resistance studies of high-strength concretes carried out at NIIZHB named after A.A. Gvozdev yielded experimental data required to subsequently develop a standardized approach to the normalization of freeze-thaw/frost-salt resistance parameters characterizing high-strength concretes.","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129374215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-18DOI: 10.37538/2224-9494-2022-2(33)-44-62
N. V. Barannik, S. V. Kotov, E. Potapova, S. S. Malakhin
Introduction. The heat emission of concrete during its hardening in adiabatic conditions is typically determined according to the GOST 24316 State Satndard. This method is quite limited in research possibilities, since under the conditions of constantly increasing temperature, it appears impossible to adequately assess the influence of various components or hardening conditions on the processes occurring during the concrete hardening. The assessment of the heat emission during the isothermal hardening allows much more information about the hardening process of the studied material to be obtained. The direct determination of the concrete heat emission during hardening in isothermal conditions appears to be extremely difficult in technical aspect.Aim. The study is aimed at developing a method for determining the heat emission of the concrete in isothermal conditions.Materials and methods. The GOST 31108-2016 TsEM I 52.5N portland cement, quartz sand, crushed gabbrodiabase, and the GOST 23732-2011 mixing water were used in the study. The strength of concrete samples was determined in accordance with the GOST 10180-2012 State Standard. The TAM Air (TA Instruments) isothermal calorimeter was used for calorimetric studies.Results. As a result of the performed studies, a method for determining the concrete heat emission in isothermal conditions was developed on the basis of assessment of the heat emission during the hardening of model mixtures reflecting the composition of the studied concrete. The optimal particle size of the sand and crushed stone fractions for model mixtures comprises 0.16–0.315 mm. The heat emission during the isothermal hardening of 10 model mixtures reflecting the composition of the studied concrete grades was determined. The strength class of 10 concrete compositions differing in cement content was established. The dependence of the heat emitted by model mixtures on the strength classes of the studied concrete compositions was determined. The heat emission of model mixtures during the isothermal hardening was established to be directly dependent on the strength of the studied concrete compositions.Conclusions. The determination of the amount of heat emitted by model mixtures reflecting the composition of concrete mixtures during the isothermal hardening represents a useful cost-effective test significantly accelerating and facilitating the process of control and design of concrete compositions.
介绍。混凝土在绝热条件下硬化过程中的放热量通常根据GOST 24316国家标准确定。这种方法的研究可能性非常有限，因为在温度不断升高的条件下，似乎不可能充分评估各种成分或硬化条件对混凝土硬化过程的影响。对等温硬化过程中热发射的评估可以获得更多关于所研究材料硬化过程的信息。在等温条件下直接测定混凝土硬化过程中的放热量在技术上是极其困难的。本研究的目的是开发一种在等温条件下测定混凝土放热的方法。材料和方法。采用GOST 23798 -2016型TsEM I 52.5N硅酸盐水泥、石英砂、破碎辉长岩、GOST 23732-2011型掺合水。混凝土试样强度按GOST 10180-2012国家标准进行测定。采用TAM Air (TA Instruments)等温量热计进行量热研究。作为所进行的研究的结果，在评估反映所研究混凝土成分的模型混合物硬化过程中的热辐射的基础上，开发了一种确定等温条件下混凝土热辐射的方法。模型混合料中砂、碎石组分的最佳粒径为0.16 ~ 0.315 mm。测定了反映所研究混凝土等级组成的10种模型混合物在等温硬化过程中的放热。建立了不同水泥掺量的10种混凝土组成的强度等级。确定了模型混合物所散发的热量与所研究混凝土成分强度等级的关系。在等温硬化过程中，模型混合物的放热量直接依赖于所研究的混凝土成分的强度。在等温硬化过程中，反映混凝土混合物组成的模型混合物释放的热量的测定是一种有用的、具有成本效益的试验，可显著加快和促进混凝土组成的控制和设计过程。
{"title":"Determination of the concrete heat emission during its hardening in isothermal conditions","authors":"N. V. Barannik, S. V. Kotov, E. Potapova, S. S. Malakhin","doi":"10.37538/2224-9494-2022-2(33)-44-62","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-44-62","url":null,"abstract":"Introduction. The heat emission of concrete during its hardening in adiabatic conditions is typically determined according to the GOST 24316 State Satndard. This method is quite limited in research possibilities, since under the conditions of constantly increasing temperature, it appears impossible to adequately assess the influence of various components or hardening conditions on the processes occurring during the concrete hardening. The assessment of the heat emission during the isothermal hardening allows much more information about the hardening process of the studied material to be obtained. The direct determination of the concrete heat emission during hardening in isothermal conditions appears to be extremely difficult in technical aspect.Aim. The study is aimed at developing a method for determining the heat emission of the concrete in isothermal conditions.Materials and methods. The GOST 31108-2016 TsEM I 52.5N portland cement, quartz sand, crushed gabbrodiabase, and the GOST 23732-2011 mixing water were used in the study. The strength of concrete samples was determined in accordance with the GOST 10180-2012 State Standard. The TAM Air (TA Instruments) isothermal calorimeter was used for calorimetric studies.Results. As a result of the performed studies, a method for determining the concrete heat emission in isothermal conditions was developed on the basis of assessment of the heat emission during the hardening of model mixtures reflecting the composition of the studied concrete. The optimal particle size of the sand and crushed stone fractions for model mixtures comprises 0.16–0.315 mm. The heat emission during the isothermal hardening of 10 model mixtures reflecting the composition of the studied concrete grades was determined. The strength class of 10 concrete compositions differing in cement content was established. The dependence of the heat emitted by model mixtures on the strength classes of the studied concrete compositions was determined. The heat emission of model mixtures during the isothermal hardening was established to be directly dependent on the strength of the studied concrete compositions.Conclusions. The determination of the amount of heat emitted by model mixtures reflecting the composition of concrete mixtures during the isothermal hardening represents a useful cost-effective test significantly accelerating and facilitating the process of control and design of concrete compositions. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132649652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-14DOI: 10.37538/2224-9494-2022-2(33)-194-212
V. Falikman, P. N. Sirotin
Introduction. With the introduction of a new national standard GOST 32703–2014 “Automobile roads of general use. Crushed stone and gravel from rocks. Technical requirements”, mining companies producing crushed stone from dense rocks faced the problem of ensuring the production output in compliance with two significantly different standards, both regulating the properties of crushed stone. The complexity of a balanced approach to production planning and stock reserve maintenance determines the need to assess the possibility of using crushed stone produced according to GOST 32703 when producing construction works, concrete mixes, and concrete for general civil construction.Aim: to define the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction.Materials and methods. Crushed stone produced according to GOST 8267 and GOST 32703 from solid rocks of various origin—granite, gabbro-diabase, and dense limestone—was used as coarse aggregates for concrete production. Comparative tests of concrete mixes prepared from crushed stone from one deposit but classified in accordance with two different standards were performed. The main quality parameters of concrete mixes were determined by testing methods according to GOST 10181, while the mechanic al and physical properties of concrete mixes were determined by testing methods according to GOST 10180.Results. The study showed a certain compatibility of the quality properties of concrete mixes and the mechanical and physical properties of concrete filled with crushed stone, which is classified according to different standards but having the same content of lamellar and needle-shaped particles.Conclusions. Recommendations are formulated on the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction. The key issues concerned with simultaneous application of two different standards are indicated.
{"title":"Prospects of using crushed stone in accordance with GOST 32703 to produce concrete for general civil construction","authors":"V. Falikman, P. N. Sirotin","doi":"10.37538/2224-9494-2022-2(33)-194-212","DOIUrl":"https://doi.org/10.37538/2224-9494-2022-2(33)-194-212","url":null,"abstract":"Introduction. With the introduction of a new national standard GOST 32703–2014 “Automobile roads of general use. Crushed stone and gravel from rocks. Technical requirements”, mining companies producing crushed stone from dense rocks faced the problem of ensuring the production output in compliance with two significantly different standards, both regulating the properties of crushed stone. The complexity of a balanced approach to production planning and stock reserve maintenance determines the need to assess the possibility of using crushed stone produced according to GOST 32703 when producing construction works, concrete mixes, and concrete for general civil construction.Aim: to define the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction.Materials and methods. Crushed stone produced according to GOST 8267 and GOST 32703 from solid rocks of various origin—granite, gabbro-diabase, and dense limestone—was used as coarse aggregates for concrete production. Comparative tests of concrete mixes prepared from crushed stone from one deposit but classified in accordance with two different standards were performed. The main quality parameters of concrete mixes were determined by testing methods according to GOST 10181, while the mechanic al and physical properties of concrete mixes were determined by testing methods according to GOST 10180.Results. The study showed a certain compatibility of the quality properties of concrete mixes and the mechanical and physical properties of concrete filled with crushed stone, which is classified according to different standards but having the same content of lamellar and needle-shaped particles.Conclusions. Recommendations are formulated on the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction. The key issues concerned with simultaneous application of two different standards are indicated. ","PeriodicalId":169749,"journal":{"name":"Bulletin of Science and Research Center of Construction","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116785906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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