Structural design has a significant impact on the overall cost of truss structures. In order to reduce the cost of a structure it is important to support designers' decision making starting from the early design phase. In this study, an optimization workflow is proposed, developed and implemented using well known generative design and Building Information Modeling (BIM) tools to achieve a cost-optimal design of a truss structure in the early design phase. Generative design aims to develop products that are lighter, stronger, more efficient and tailored to the specific needs of end users. Generative design tools allow users to create efficient designs via optimizing factors such as cost, weight, energy efficiency and performance. The aim of this study was to develop an optimization workflow to find and model the minimum weight / minimum cost design alternative in the early design phase using generative design, structural analysis and BIM tools in an integrated manner. The goal for the optimization was determined as finding the minimum weight (thus minimum cost) structure among the generated design alternatives. The single span steel truss was selected as the structure to be optimized, and optimization scenarios were prepared and implemented to determine the structural components of the truss with minimum weight. The results demonstrated that through integrated use of structural analysis, generative design and BIM tools minimum-weight truss design can be realized easily and practically.
{"title":"A generative design-to-BIM workflow for minimum weight plane truss design","authors":"Berk Malgit, U. Isikdag, G. Bekdaş, Melda Yucel","doi":"10.7764/rdlc.21.2.473","DOIUrl":"https://doi.org/10.7764/rdlc.21.2.473","url":null,"abstract":"Structural design has a significant impact on the overall cost of truss structures. In order to reduce the cost of a structure it is important to support designers' decision making starting from the early design phase. In this study, an optimization workflow is proposed, developed and implemented using well known generative design and Building Information Modeling (BIM) tools to achieve a cost-optimal design of a truss structure in the early design phase. Generative design aims to develop products that are lighter, stronger, more efficient and tailored to the specific needs of end users. Generative design tools allow users to create efficient designs via optimizing factors such as cost, weight, energy efficiency and performance. The aim of this study was to develop an optimization workflow to find and model the minimum weight / minimum cost design alternative in the early design phase using generative design, structural analysis and BIM tools in an integrated manner. The goal for the optimization was determined as finding the minimum weight (thus minimum cost) structure among the generated design alternatives. The single span steel truss was selected as the structure to be optimized, and optimization scenarios were prepared and implemented to determine the structural components of the truss with minimum weight. The results demonstrated that through integrated use of structural analysis, generative design and BIM tools minimum-weight truss design can be realized easily and practically.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bitumen is modified with various modifiers to diminish the deformation occurred in flexible pavements due to traffic loads and the effects of climate. Polymer modification and more specifically Styrene-Butadiene-Styrene (SBS) copolymer modification is one of the most common methods to enhance the physical properties of bitumen. However, the polymer modified bitumens could exhibit different rheological properties compared to original bitumen. In this work, it is aimed to investigate the effects of SBS copolymer on thermorheological properties of bitumen by means of state of art test methods. To this end, a rheological program including small amplitude oscillation shear test (SAOS), construction of master curves by using time-temperature superposition (TTS) principle, determination of zero shear viscosity (ZSV) and multiple shear creep recovery tests (MSCR) were employed along with other fundamental tests. SAOS test result signifies a positive effect of SBS on the viscoelastic deformation nature of bitumen. The master curves of the complex viscosity of binders reveal that SBS modifier reduced the Newtonian flow properties of bitumen. The decrements in non-recoverable creep compliance and the increment in percent recovery signify that SBS modifier has dramatically enhanced the applicability of bitumen as a binder in flexible pavement at mid to high-temperature ranges.
{"title":"Investigation of physical properties of base and SBS modified bitumens by rheological test methods","authors":"Taylan Gunay","doi":"10.7764/rdlc.21.2.281","DOIUrl":"https://doi.org/10.7764/rdlc.21.2.281","url":null,"abstract":"Bitumen is modified with various modifiers to diminish the deformation occurred in flexible pavements due to traffic loads and the effects of climate. Polymer modification and more specifically Styrene-Butadiene-Styrene (SBS) copolymer modification is one of the most common methods to enhance the physical properties of bitumen. However, the polymer modified bitumens could exhibit different rheological properties compared to original bitumen. In this work, it is aimed to investigate the effects of SBS copolymer on thermorheological properties of bitumen by means of state of art test methods. To this end, a rheological program including small amplitude oscillation shear test (SAOS), construction of master curves by using time-temperature superposition (TTS) principle, determination of zero shear viscosity (ZSV) and multiple shear creep recovery tests (MSCR) were employed along with other fundamental tests. SAOS test result signifies a positive effect of SBS on the viscoelastic deformation nature of bitumen. The master curves of the complex viscosity of binders reveal that SBS modifier reduced the Newtonian flow properties of bitumen. The decrements in non-recoverable creep compliance and the increment in percent recovery signify that SBS modifier has dramatically enhanced the applicability of bitumen as a binder in flexible pavement at mid to high-temperature ranges.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Analysis and design of the structure are the most critical steps in the pre-construction steps involved. Nowadays, as technology is well developed, there is plenty of software available to carry over the analysis and design of any structures in a short period. In every software, the building model with all storey will be modelled, and loads are applied to the modelled structure on respective members, and their responses will be studied for the whole structure. But in reality, the building will be constructed in sequence as a step-by-step process, i.e., storey after storey with their respective loads, which may produce different responses. This analysis with sequential loading at each step is called Construction Sequence Analysis (CSA). In the present project work, the ten-storey setback building with a built-up area of 25m x 30m placed on the slope of 10°, assumed to be situated in Darjeeling, is modelled in ETABS software. The loads, namely gravity and lateral loads are applied to the developed model. Then the model is analyzed for different loads and their combinations as prescribed by IS codes. The combinations that produce high response are selected and dead load in those combinations are replaced with three modes: CSA without P-Delta effect, CSA with P-Delta effect, and CSA with P-Delta and Time-dependent effects combined. Thus the model is analyzed with these three additional combinations along with selected conventional load combinations. The various comparisons such as storey displacement, and storey drift between these four combinations of analysis were studied, and results were discussed. The building design is also done based on the analysis performed.
结构的分析和设计是施工前最关键的步骤。如今，随着技术的发展，有大量的软件可以在短时间内进行任何结构的分析和设计。在每个软件中，将对所有楼层的建筑模型进行建模，并将荷载施加到模型结构的各个构件上，并研究它们对整个结构的响应。但在现实中，建筑物将按顺序逐步建造，即一层接一层地进行施工，其各自的荷载可能会产生不同的响应。这种在每个步骤上按顺序加载的分析称为构造序列分析(CSA)。在目前的项目工作中，假定位于大吉岭的10°斜坡上的建筑面积为25m x 30m的10层后退建筑，在ETABS软件中进行建模。荷载即重力荷载和侧向荷载作用于所建立的模型。然后根据is规范的规定，对不同荷载及其组合进行了分析。选择产生高响应的组合，并将这些组合中的恒载替换为三种模式:无p - δ效应的CSA、有p - δ效应的CSA和同时具有p - δ和时间相关效应的CSA。因此，将这三种附加组合与选定的常规荷载组合一起对模型进行分析。对这四种分析组合间的层间位移、层间漂移等进行了比较，并对结果进行了讨论。在分析的基础上进行了建筑设计。
{"title":"Construction sequence analysis of multi-storey setback building placed in slope with p-delta and time-dependent effects","authors":"G. Balaji, S. Vivek","doi":"10.7764/rdlc.21.2.408","DOIUrl":"https://doi.org/10.7764/rdlc.21.2.408","url":null,"abstract":"Analysis and design of the structure are the most critical steps in the pre-construction steps involved. Nowadays, as technology is well developed, there is plenty of software available to carry over the analysis and design of any structures in a short period. In every software, the building model with all storey will be modelled, and loads are applied to the modelled structure on respective members, and their responses will be studied for the whole structure. But in reality, the building will be constructed in sequence as a step-by-step process, i.e., storey after storey with their respective loads, which may produce different responses. This analysis with sequential loading at each step is called Construction Sequence Analysis (CSA). In the present project work, the ten-storey setback building with a built-up area of 25m x 30m placed on the slope of 10°, assumed to be situated in Darjeeling, is modelled in ETABS software. The loads, namely gravity and lateral loads are applied to the developed model. Then the model is analyzed for different loads and their combinations as prescribed by IS codes. The combinations that produce high response are selected and dead load in those combinations are replaced with three modes: CSA without P-Delta effect, CSA with P-Delta effect, and CSA with P-Delta and Time-dependent effects combined. Thus the model is analyzed with these three additional combinations along with selected conventional load combinations. The various comparisons such as storey displacement, and storey drift between these four combinations of analysis were studied, and results were discussed. The building design is also done based on the analysis performed.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Şevin Ekmen, Kasım Mermerdaş, Z. Alğın, Yusuf Işıker
The main aim of the current study is to search the impact of variable matrix phase features on fly ash based lightweight geopolymer mortars (LWGM). Another scope of the study is to obtain performance oriented optimum mixture proportions through response surface method (RSM). In order to have low unit weight for LWGMs, pumice aggregate was utilized as a part of the aggregate. The investigated engineering properties are water absorption, drying shrinkage and thermal conductivity. By performing optimization analysis, it was aimed to obtain the best numerical models representing the experimental results depending on the input variables. The decrease of liquid (alkali activators) to powder (fly ash) ratio, Na2SiO3 solution to NaOH solution ratio and increase of sodium hydroxide molarity led to improvement of compressive strength. Dry thermal conductivity values in dry state were observed to be less than those of saturated ones. Moreover, the higher sodium hydroxide molarity and lower Na2SiO3 solution to NaOH solution ratios, and liquid to powder ratios resulted in further shrinkage reduction. Depending on the goals of maximum compressive strength, minimum water absorption, and drying shrinkage, optimum values for molarity, SS/SH, and l/p factors were determined as 14 M, 1.586, and 0.45, respectively.
{"title":"Response surface optimization of geopolymer mix parameters in terms of key engineering properties","authors":"Şevin Ekmen, Kasım Mermerdaş, Z. Alğın, Yusuf Işıker","doi":"10.7764/rdlc.21.3.631","DOIUrl":"https://doi.org/10.7764/rdlc.21.3.631","url":null,"abstract":"The main aim of the current study is to search the impact of variable matrix phase features on fly ash based lightweight geopolymer mortars (LWGM). Another scope of the study is to obtain performance oriented optimum mixture proportions through response surface method (RSM). In order to have low unit weight for LWGMs, pumice aggregate was utilized as a part of the aggregate. The investigated engineering properties are water absorption, drying shrinkage and thermal conductivity. By performing optimization analysis, it was aimed to obtain the best numerical models representing the experimental results depending on the input variables. The decrease of liquid (alkali activators) to powder (fly ash) ratio, Na2SiO3 solution to NaOH solution ratio and increase of sodium hydroxide molarity led to improvement of compressive strength. Dry thermal conductivity values in dry state were observed to be less than those of saturated ones. Moreover, the higher sodium hydroxide molarity and lower Na2SiO3 solution to NaOH solution ratios, and liquid to powder ratios resulted in further shrinkage reduction. Depending on the goals of maximum compressive strength, minimum water absorption, and drying shrinkage, optimum values for molarity, SS/SH, and l/p factors were determined as 14 M, 1.586, and 0.45, respectively.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francielle Coelho dos Santos, Michele Tereza Marques Carvalho, Maria Carolina Gomes de Oliveira Brandstetter
Decision-making regarding building performance in all construction project phases is a complex task. This article addresses the challenge of managing building performance information throughout construction project phases. It proposes a tool that assists in verifying the building performance requirements for different stakeholders and supports the integration of this information within the BIM process. The developed tool allows the launch, monitoring, and creation of a database with information about the project, the work, and the stakeholders. A practical study was chosen to test this tool. Its result is particularly meaningful to all stakeholders, as it prioritizes the information and underlying activities for the collaborative project development among the participants. In summary, the information integration related to the requirements to guarantee the building performance, co-related to the construction project development phases, is essential for improving internal processes. It is worth mentioning that managing this information is not a simple process and requires contextual knowledge, leadership, and management and communication skills.
{"title":"Tool for the integration of building performance information within the BIM process","authors":"Francielle Coelho dos Santos, Michele Tereza Marques Carvalho, Maria Carolina Gomes de Oliveira Brandstetter","doi":"10.7764/rdlc.21.3.645","DOIUrl":"https://doi.org/10.7764/rdlc.21.3.645","url":null,"abstract":"Decision-making regarding building performance in all construction project phases is a complex task. This article addresses the challenge of managing building performance information throughout construction project phases. It proposes a tool that assists in verifying the building performance requirements for different stakeholders and supports the integration of this information within the BIM process. The developed tool allows the launch, monitoring, and creation of a database with information about the project, the work, and the stakeholders. A practical study was chosen to test this tool. Its result is particularly meaningful to all stakeholders, as it prioritizes the information and underlying activities for the collaborative project development among the participants. In summary, the information integration related to the requirements to guarantee the building performance, co-related to the construction project development phases, is essential for improving internal processes. It is worth mentioning that managing this information is not a simple process and requires contextual knowledge, leadership, and management and communication skills.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Milena Mesa-Lavista, José Álvarez-Pérez, Jorge H. Chávez-Gómez, Gerardo Del Jesús Fajardo San Miguel, Diego Cavazos de Lira, F. Ruvalcaba-Ayala
Spiral ties with rectangular cross sections have been developed as a new technology in construction, reducing the workforce in the reinforcement production series, because the worker does not have to place the tie reinforcement for the columns on the construction site. In this paper, a new type of tie was evaluated in short tie-columns subjected to axial compression to be applied in confined masonry. A comparison was made in this paper among spiral ties, with circular and rectangular cross sections, and traditional closed ties. The main aim of this research is to prove that these rectangular cross-section spiral ties can be used in tie columns for confined masonry structures. Twenty-one specimens were tested to investigate their structural behavior. As a part of the results, maximum loads, strains, load-displacement curves, and stress-strain relationships, were obtained based on testing standards, for both specimens and component materials. In addition, the fracture energy in compression and the ductility index were assessed. These results demonstrate that spiral ties with rectangular cross sections have an efficient structural response compared to traditional and circular spiral ties.
{"title":"Axial compressive behavior of short tie-columns with strapping spiral ties","authors":"Milena Mesa-Lavista, José Álvarez-Pérez, Jorge H. Chávez-Gómez, Gerardo Del Jesús Fajardo San Miguel, Diego Cavazos de Lira, F. Ruvalcaba-Ayala","doi":"10.7764/rdlc.21.3.657","DOIUrl":"https://doi.org/10.7764/rdlc.21.3.657","url":null,"abstract":"Spiral ties with rectangular cross sections have been developed as a new technology in construction, reducing the workforce in the reinforcement production series, because the worker does not have to place the tie reinforcement for the columns on the construction site. In this paper, a new type of tie was evaluated in short tie-columns subjected to axial compression to be applied in confined masonry. A comparison was made in this paper among spiral ties, with circular and rectangular cross sections, and traditional closed ties. The main aim of this research is to prove that these rectangular cross-section spiral ties can be used in tie columns for confined masonry structures. Twenty-one specimens were tested to investigate their structural behavior. As a part of the results, maximum loads, strains, load-displacement curves, and stress-strain relationships, were obtained based on testing standards, for both specimens and component materials. In addition, the fracture energy in compression and the ductility index were assessed. These results demonstrate that spiral ties with rectangular cross sections have an efficient structural response compared to traditional and circular spiral ties.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After the construction of the Keban Dam, some settlements with historical, cultural, and natural value were flooded. A scientific committee consisting of academicians and public authorities decided to the relocation of the buildings including the historical Çelebiağa Mosque. In this study, the seismic soil-structure interaction analysis of the historical Çelebiağa Mosque, which was dismantled and reconstructed in a separate region due to the construction of the Keban Dam was carried out. The analysis of the masonry mosque was performed with the SAP2000 finite element analysis software. The Winkler foundation model was used to idealize the soil environment on which the historical mosque was built. The effects of soil-structure interaction on historical masonry mosque were examined in terms of transmitted acceleration, response spectra, and lateral displacement at various heights of the structure. Depending on the results of the analysis, the effects of soil-structure interaction of a reconstructed historical masonry building were investigated. PGA was obtained as 0.51g at the flag level of the minaret under the Kocaeli earthquake and 0.94g under the Sivrice earthquake. Again, the maximum horizontal displacements of the minaret at the flag level were obtained as 11 cm and 8.5 cm under the Kocaeli and Sivrice earthquakes. The behavior of historical masonry structures under earthquake loads has been interpreted by considering the geological conditions.
{"title":"Soil-structure interaction analysis of Çelebiağa Mosque, Pertek-Türkiye","authors":"Özgür Yıldız, E. Doğan","doi":"10.7764/rdlc.21.3.749","DOIUrl":"https://doi.org/10.7764/rdlc.21.3.749","url":null,"abstract":"After the construction of the Keban Dam, some settlements with historical, cultural, and natural value were flooded. A scientific committee consisting of academicians and public authorities decided to the relocation of the buildings including the historical Çelebiağa Mosque. In this study, the seismic soil-structure interaction analysis of the historical Çelebiağa Mosque, which was dismantled and reconstructed in a separate region due to the construction of the Keban Dam was carried out. The analysis of the masonry mosque was performed with the SAP2000 finite element analysis software. The Winkler foundation model was used to idealize the soil environment on which the historical mosque was built. The effects of soil-structure interaction on historical masonry mosque were examined in terms of transmitted acceleration, response spectra, and lateral displacement at various heights of the structure. Depending on the results of the analysis, the effects of soil-structure interaction of a reconstructed historical masonry building were investigated. PGA was obtained as 0.51g at the flag level of the minaret under the Kocaeli earthquake and 0.94g under the Sivrice earthquake. Again, the maximum horizontal displacements of the minaret at the flag level were obtained as 11 cm and 8.5 cm under the Kocaeli and Sivrice earthquakes. The behavior of historical masonry structures under earthquake loads has been interpreted by considering the geological conditions.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71305915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Serin, Muhammet Ahmet Oğuzhanoğlu, C. Kayadelen
In many countries of the world, rigid and flexible pavements are widely used. Some of the external factors such as stresses and displacements play major role in the design of pavement layers such as coating, base and sub-base. Although empirical formulas and methods were used in the calculation and design of the pavement layers, complexity of today's transportation engineering demands effectiveness of the empirical formulas were diminished. Nowadays complex problems can be easily simulated and solved thanks to the higher analysis capabilities of the computer-aided softwares. In this study, the stress distributions and displacements were examined under traffic loads in rigid and flexible pavements with different coating layer thicknesses (30 mm, 50mm, 70mm, 100 mm, and 150 mm) by using finite element method. As a result, the vertical displacement in the flexible pavements were obtained as 5% higher than the vertical displacement in the rigid pavements. Based on the stress distribution results, the stress values of flexible pavements were 60% lower than the stress values of the rigid pavements. Moreover, It was determined that the stresses in the rigid pavements remain in the coating layer, while the stresses in the flexible pavements reach the base and sub-base. In addition, regression models have been developed to predict stress and displacements by using layer thicknesses. High correlation and determination coefficient values (> 0.90) were achieved based on the regression analysis both in flexible and rigid pavements.
{"title":"Comparative analysis of stress distributions and displacements in rigid and flexible pavements via finite element method","authors":"S. Serin, Muhammet Ahmet Oğuzhanoğlu, C. Kayadelen","doi":"10.7764/rdlc.20.2.321","DOIUrl":"https://doi.org/10.7764/rdlc.20.2.321","url":null,"abstract":"In many countries of the world, rigid and flexible pavements are widely used. Some of the external factors such as stresses and displacements play major role in the design of pavement layers such as coating, base and sub-base. Although empirical formulas and methods were used in the calculation and design of the pavement layers, complexity of today's transportation engineering demands effectiveness of the empirical formulas were diminished. Nowadays complex problems can be easily simulated and solved thanks to the higher analysis capabilities of the computer-aided softwares. In this study, the stress distributions and displacements were examined under traffic loads in rigid and flexible pavements with different coating layer thicknesses (30 mm, 50mm, 70mm, 100 mm, and 150 mm) by using finite element method. As a result, the vertical displacement in the flexible pavements were obtained as 5% higher than the vertical displacement in the rigid pavements. Based on the stress distribution results, the stress values of flexible pavements were 60% lower than the stress values of the rigid pavements. Moreover, It was determined that the stresses in the rigid pavements remain in the coating layer, while the stresses in the flexible pavements reach the base and sub-base. In addition, regression models have been developed to predict stress and displacements by using layer thicknesses. High correlation and determination coefficient values (> 0.90) were achieved based on the regression analysis both in flexible and rigid pavements.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2021-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45006482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For this paper, silica fume (SF), slag (S), and colemanite waste (C) were added to metakaolin (MK)-based geopolymer composites and exposed to 10% (by volume) hydrochloric acid (HCl) and sulfuric acid (H2SO4) solutions for up to 12 months. Geopolymer composites were examined in terms of weight loss, compressive strength, and flexural strength at 3, 6, and 12 months in solutions. Furthermore, Scanning Electron Microscopy (SEM), Micro-computed Tomography (micro-CT), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analyses were carried out to examine the microstructure before and after acid attacks. An important decrease in flexural and compressive strengths was seen when geopolymer mortars were subjected to sulfuric and hydrochloric acid attacks. The main cause of this situation is the deterioration of the oxy-aluminum bridge (-Al-Si-O) when exposed to sulfuric and hydrochloric acid. The oxy-aluminum bridge (-Al-Si-O), the primary factor in the geopolymer matrix, plays a significant role in consolidating the gel and enhancing the bond formed between the matrix components. Despite this, geopolymer mortar samples maintain the aluminosilicate structure. Compared to hydrochloric acid, sulfuric acid is a stronger solution, resulting in a greater loss of compressive and flexural strengths.
{"title":"Long-term sulfuric and hydrochloric acid resistance of silica fume and colemanite waste reinforced metakaolin-based geopolymers","authors":"Yurdakul Aygörmez, O. Canpolat","doi":"10.7764/rdlc.20.2.291","DOIUrl":"https://doi.org/10.7764/rdlc.20.2.291","url":null,"abstract":"For this paper, silica fume (SF), slag (S), and colemanite waste (C) were added to metakaolin (MK)-based geopolymer composites and exposed to 10% (by volume) hydrochloric acid (HCl) and sulfuric acid (H2SO4) solutions for up to 12 months. Geopolymer composites were examined in terms of weight loss, compressive strength, and flexural strength at 3, 6, and 12 months in solutions. Furthermore, Scanning Electron Microscopy (SEM), Micro-computed Tomography (micro-CT), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analyses were carried out to examine the microstructure before and after acid attacks. An important decrease in flexural and compressive strengths was seen when geopolymer mortars were subjected to sulfuric and hydrochloric acid attacks. The main cause of this situation is the deterioration of the oxy-aluminum bridge (-Al-Si-O) when exposed to sulfuric and hydrochloric acid. The oxy-aluminum bridge (-Al-Si-O), the primary factor in the geopolymer matrix, plays a significant role in consolidating the gel and enhancing the bond formed between the matrix components. Despite this, geopolymer mortar samples maintain the aluminosilicate structure. Compared to hydrochloric acid, sulfuric acid is a stronger solution, resulting in a greater loss of compressive and flexural strengths.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2021-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45324885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Jagan, Anand Nagar Krishnankoil Education, T. R. Neelakantan, P. S. Kumar
Increased demand for natural aggregates (NA) due to infrastructural development has necessitated the use of alternative aggregates in the field of construction. One such option is the utilization of construction and demolition wastes, preferably named as recycled coarse aggregates (RCA) to produce a sustainable recycled aggregate concrete (RAC). Perhaps, the quality of RCA is usually poor due to the presence of adhered mortar on its surface affecting the strength and durability properties of RAC. Consequently, it is essential to improve the behavior of recycled aggregate concrete. In order to improve the recycled concrete aggregate, four different processing techniques such as two-stage mixing approach (TSMA), mortar mixing approach (MMA), sand enveloped mixing approach (SEMA) and double mixing approach (DMA) were used to improve the quality of RAC. This paper aims at providing a comparative study on the suitability of different mixing approaches and their influence over the fresh and hardened properties of recycled aggregate concrete. The performance behaviour of RAC was evaluated at 7, 14, 28 and 90 days with various percentage replacements of RCA at w/c ratios of 0.45 and 0.5. Experimental results indicate that the strength of concrete made of 100% RCA was equivalent to the target strength at 90 days. Also, among the various mixing processing techniques, MMA shows better fresh and hardened properties of concrete at different curing ages. Micro-structural investigations through SEM were performed to investigate the modification in the ITZ of the RAC through MMA approach.
{"title":"Mechanical properties of recycled aggregate concrete surface treated by variation in mixing approaches","authors":"S. Jagan, Anand Nagar Krishnankoil Education, T. R. Neelakantan, P. S. Kumar","doi":"10.7764/rdlc.20.2.236","DOIUrl":"https://doi.org/10.7764/rdlc.20.2.236","url":null,"abstract":"Increased demand for natural aggregates (NA) due to infrastructural development has necessitated the use of alternative aggregates in the field of construction. One such option is the utilization of construction and demolition wastes, preferably named as recycled coarse aggregates (RCA) to produce a sustainable recycled aggregate concrete (RAC). Perhaps, the quality of RCA is usually poor due to the presence of adhered mortar on its surface affecting the strength and durability properties of RAC. Consequently, it is essential to improve the behavior of recycled aggregate concrete. In order to improve the recycled concrete aggregate, four different processing techniques such as two-stage mixing approach (TSMA), mortar mixing approach (MMA), sand enveloped mixing approach (SEMA) and double mixing approach (DMA) were used to improve the quality of RAC. This paper aims at providing a comparative study on the suitability of different mixing approaches and their influence over the fresh and hardened properties of recycled aggregate concrete. The performance behaviour of RAC was evaluated at 7, 14, 28 and 90 days with various percentage replacements of RCA at w/c ratios of 0.45 and 0.5. Experimental results indicate that the strength of concrete made of 100% RCA was equivalent to the target strength at 90 days. Also, among the various mixing processing techniques, MMA shows better fresh and hardened properties of concrete at different curing ages. Micro-structural investigations through SEM were performed to investigate the modification in the ITZ of the RAC through MMA approach.","PeriodicalId":54473,"journal":{"name":"Revista de la Construccion","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48113696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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