Pub Date : 2023-12-04DOI: 10.1186/s40069-023-00635-y
Alaa M. Rashad
As known, calcium oxide (CaO) is an alkaline material, which can be used widely to increase the clay-containing soils load carrying capacity, to produce aerated concrete and calcium aluminate cement. In the last few years, introducing CaO into alkali-activated materials (AAMs) became a hot topic and attained more attention than other times. Generally, CaO can be incorporated into AAMs as an additive/a part of the main precursor and a sole activator without/with an auxiliary activator. Incorporating CaO into the matrices may improve some properties and worsen others. This mainly depends on the ratio of CaO, curing conditions, activator type and activator concentration, precursor type and testing age. This review collected, summarized and analyzed the available studies focused on the effect of CaO on the fresh (reaction kinetic, workability, setting time) and hardened (mechanical strength, durability and length change) properties of AAMs. In addition, some recommendations for future works were included. The results showed that the inclusion of CaO in AAMs decreased workability and setting time. In spite of there are contradictory results about the effect of CaO on the compressive strength of AAMs, most of them reported higher compressive strength, especially at the early ages. The incorporation of CaO up to 5% in the matrix is more effective than the incorporation of higher ratios. The inclusion of CaO in the matrix decreased water absorption, decreased total porosity, increased wetting/drying as well as acid attack resistivity. The CaO (5–10%) can be used as a sole activator for precursors. Auxiliary activators such as Al2(SO4)3, Na2CO3, Na2SiO3, Na2SO4, CaSO4, NaOH, Ca(NO3)2, NaNO3, Mg(NO3)2, Mg(HCOO)2, Ca(HCOO)2, SO3, gypsum and MgO can be used to enhance the compressive strength of CaO-activated materials, especially at the early ages.
{"title":"A Concise on the Effect of Calcium Oxide on the Properties of Alkali-Activated Materials: A Manual for Civil Engineers","authors":"Alaa M. Rashad","doi":"10.1186/s40069-023-00635-y","DOIUrl":"https://doi.org/10.1186/s40069-023-00635-y","url":null,"abstract":"<p>As known, calcium oxide (CaO) is an alkaline material, which can be used widely to increase the clay-containing soils load carrying capacity, to produce aerated concrete and calcium aluminate cement. In the last few years, introducing CaO into alkali-activated materials (AAMs) became a hot topic and attained more attention than other times. Generally, CaO can be incorporated into AAMs as an additive/a part of the main precursor and a sole activator without/with an auxiliary activator. Incorporating CaO into the matrices may improve some properties and worsen others. This mainly depends on the ratio of CaO, curing conditions, activator type and activator concentration, precursor type and testing age. This review collected, summarized and analyzed the available studies focused on the effect of CaO on the fresh (reaction kinetic, workability, setting time) and hardened (mechanical strength, durability and length change) properties of AAMs. In addition, some recommendations for future works were included. The results showed that the inclusion of CaO in AAMs decreased workability and setting time. In spite of there are contradictory results about the effect of CaO on the compressive strength of AAMs, most of them reported higher compressive strength, especially at the early ages. The incorporation of CaO up to 5% in the matrix is more effective than the incorporation of higher ratios. The inclusion of CaO in the matrix decreased water absorption, decreased total porosity, increased wetting/drying as well as acid attack resistivity. The CaO (5–10%) can be used as a sole activator for precursors. Auxiliary activators such as Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>, Na<sub>2</sub>CO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, Na<sub>2</sub>SO<sub>4</sub>, CaSO<sub>4</sub>, NaOH, Ca(NO<sub>3</sub>)<sub>2</sub>, NaNO<sub>3</sub>, Mg(NO<sub>3</sub>)<sub>2</sub>, Mg(HCOO)<sub>2</sub>, Ca(HCOO)<sub>2</sub>, SO<sub>3</sub>, gypsum and MgO can be used to enhance the compressive strength of CaO-activated materials, especially at the early ages.</p>","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"32 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138537176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.1186/s40069-023-00632-1
Mosaad El-Diasity, Sayed Salah, Mohamed O. R. El-Hariri, Amr A. Gamal, Tarik S. Elsalakawy
This research presents the numerical and experimental results of lateral cyclic loading applied on a two-story confined masonry structure utilizing local materials and standards. Two half-scale confined masonry structures were constructed using clay masonry units, confining columns, tie beams, and reinforced concrete slabs. The assemblies were tested up to failure using a displacement controlled loading methodology under vertical self-weight and lateral reversed cyclic loading. The walls of the assemblies have varying perforations (solid / windows / doors) to examine the influence of perforation on in-plane and out-of-plane performance. A strengthened assembly with an exterior layer of ferrocement has been used and this suggested upgrading approach enhanced the lateral resistance of the confined assembly by about (61–95%) while improving ductility and total energy absorbed by 27%. The maximum lateral drift at failure have been decreased to (23–31%), however the corresponding load for the first visible fracture have been raised by (150–175%). Furthermore, total failure has been delayed for the strengthened walls (all sides, particularly the perforated sides). Comparing distorted forms, fracture patterns, and capacity curves of finite element models included in this research yielded excellent agreement.
{"title":"Numerical and Experimental Behavior of Two-Story Confined Masonry Structure Subjected to Cyclic Loads","authors":"Mosaad El-Diasity, Sayed Salah, Mohamed O. R. El-Hariri, Amr A. Gamal, Tarik S. Elsalakawy","doi":"10.1186/s40069-023-00632-1","DOIUrl":"https://doi.org/10.1186/s40069-023-00632-1","url":null,"abstract":"<p>This research presents the numerical and experimental results of lateral cyclic loading applied on a two-story confined masonry structure utilizing local materials and standards. Two half-scale confined masonry structures were constructed using clay masonry units, confining columns, tie beams, and reinforced concrete slabs. The assemblies were tested up to failure using a displacement controlled loading methodology under vertical self-weight and lateral reversed cyclic loading. The walls of the assemblies have varying perforations (solid / windows / doors) to examine the influence of perforation on in-plane and out-of-plane performance. A strengthened assembly with an exterior layer of ferrocement has been used and this suggested upgrading approach enhanced the lateral resistance of the confined assembly by about (61–95%) while improving ductility and total energy absorbed by 27%. The maximum lateral drift at failure have been decreased to (23–31%), however the corresponding load for the first visible fracture have been raised by (150–175%). Furthermore, total failure has been delayed for the strengthened walls (all sides, particularly the perforated sides). Comparing distorted forms, fracture patterns, and capacity curves of finite element models included in this research yielded excellent agreement.</p>","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"188 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138537175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1186/s40069-023-00622-3
Woo-Young Park, Juhyuk Moon
{"title":"Machine Learning Based Reactivity Prediction of Fly Ash Type F Produced from South Korea","authors":"Woo-Young Park, Juhyuk Moon","doi":"10.1186/s40069-023-00622-3","DOIUrl":"https://doi.org/10.1186/s40069-023-00622-3","url":null,"abstract":"","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"31 ","pages":"1-13"},"PeriodicalIF":3.4,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139247077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.1186/s40069-023-00619-y
Wen Li, Hailong Wang, Wenyan Zhang
Abstract The world is facing the problem of depletion of natural sand and gravel resources, and a large amount of coal gangue solid waste is produced in Inner Mongolia, China, which has low utilization rate and causes ecological pollution. In order to improve the gangue in the mining infrastructure construction of a wide range of application prospects, the use of coal gangue as the coarse aggregate of pumice concrete is of great significance. Inner Mongolia is a cold region, and gangue mixed aggregate concrete (MFC) will certainly face the damage caused by freeze–thaw cycles. Therefore, design gangue by different volume replacement rate (0%, 20%, 40%, 60%, 80%, 100%) to replace pumice coarse aggregate. The results show that with the increase of gangue substitution rate, the mass loss rate, relative dynamic elastic modulus, and peak stress of MFC decrease, but the trend of peak strain increases. It is mainly attributed to the less Al 2 O 3 and SiO 2 content of gangue, which makes the MFC hydration products decrease with the increase of substitution rate and more original microcracks and pores in the specimens. In addition, the damage model of MFC was established by using Weibull statistical distribution theory and the principle of LEMAITRE equivalent effect variation assumption, and the damage evolution characteristics were explored by combining the experimental results. It can provide the theoretical basis for the application of MFC in cold regions.
{"title":"Damage and Deterioration Mechanism of Coal Gangue Mixed Pumice Aggregate Concrete Under Freeze–Thaw Cycles","authors":"Wen Li, Hailong Wang, Wenyan Zhang","doi":"10.1186/s40069-023-00619-y","DOIUrl":"https://doi.org/10.1186/s40069-023-00619-y","url":null,"abstract":"Abstract The world is facing the problem of depletion of natural sand and gravel resources, and a large amount of coal gangue solid waste is produced in Inner Mongolia, China, which has low utilization rate and causes ecological pollution. In order to improve the gangue in the mining infrastructure construction of a wide range of application prospects, the use of coal gangue as the coarse aggregate of pumice concrete is of great significance. Inner Mongolia is a cold region, and gangue mixed aggregate concrete (MFC) will certainly face the damage caused by freeze–thaw cycles. Therefore, design gangue by different volume replacement rate (0%, 20%, 40%, 60%, 80%, 100%) to replace pumice coarse aggregate. The results show that with the increase of gangue substitution rate, the mass loss rate, relative dynamic elastic modulus, and peak stress of MFC decrease, but the trend of peak strain increases. It is mainly attributed to the less Al 2 O 3 and SiO 2 content of gangue, which makes the MFC hydration products decrease with the increase of substitution rate and more original microcracks and pores in the specimens. In addition, the damage model of MFC was established by using Weibull statistical distribution theory and the principle of LEMAITRE equivalent effect variation assumption, and the damage evolution characteristics were explored by combining the experimental results. It can provide the theoretical basis for the application of MFC in cold regions.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"9 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136229228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-13DOI: 10.1186/s40069-023-00637-w
Ahmed M. Maglad, Walid Mansour, Bassam A. Tayeh, Mohamed Elmasry, Ahmed M. Yosri, Sabry Fayed
Abstract Fracture parameters of fiber concrete (FC) are currently a hot research area. Fracture mechanics is the field of solid mechanics that helps to study the type and propagation of cracks in materials. It uses methods of calculating the driving force on a crack and characterizes the material's resistance to fracture. Behavioral characteristics are determined by crack mouth opening displacement and the load–deflection method. This research identifies the fracture parameters of 33 notched simply supported beams made by recycled aggregate cement concrete with steel fiber. The recycled aggregate ratio in concrete has been altered to determine the effect on the mechanical and fracture properties. For determining fracture parameters, a 3-point bending single-edge notched fracture test was used. The results indicated that the steel fiber-reinforced concrete made with recycled aggregate showed similar performance and fracture characteristics compared to normal concrete. Thus, adding steel fibers to various concrete mixes considerably improved the fracture characteristics, while the brittleness was reduced with increased steel fiber content. Linear regression analysis also showed the accuracy of mechanical strength results as the value of R-square was close to unity. Displacement, ultimate load, brittleness (B), fracture toughness ( K IC ), crack mouth opening displacement (CMOD), fracture energy ( G F ), modulus of elasticity ( E ), and characteristic length ( l ch ), were determined for both conventional and recycled aggregate specimens. The “work of fracture"—by definition the formula—is the most reliable to calculate the fracture energy as the nonlinearity is related to the performance of FC.
{"title":"Experimental and Analytical Investigation of Fracture Characteristics of Steel Fiber-Reinforced Recycled Aggregate Concrete","authors":"Ahmed M. Maglad, Walid Mansour, Bassam A. Tayeh, Mohamed Elmasry, Ahmed M. Yosri, Sabry Fayed","doi":"10.1186/s40069-023-00637-w","DOIUrl":"https://doi.org/10.1186/s40069-023-00637-w","url":null,"abstract":"Abstract Fracture parameters of fiber concrete (FC) are currently a hot research area. Fracture mechanics is the field of solid mechanics that helps to study the type and propagation of cracks in materials. It uses methods of calculating the driving force on a crack and characterizes the material's resistance to fracture. Behavioral characteristics are determined by crack mouth opening displacement and the load–deflection method. This research identifies the fracture parameters of 33 notched simply supported beams made by recycled aggregate cement concrete with steel fiber. The recycled aggregate ratio in concrete has been altered to determine the effect on the mechanical and fracture properties. For determining fracture parameters, a 3-point bending single-edge notched fracture test was used. The results indicated that the steel fiber-reinforced concrete made with recycled aggregate showed similar performance and fracture characteristics compared to normal concrete. Thus, adding steel fibers to various concrete mixes considerably improved the fracture characteristics, while the brittleness was reduced with increased steel fiber content. Linear regression analysis also showed the accuracy of mechanical strength results as the value of R-square was close to unity. Displacement, ultimate load, brittleness (B), fracture toughness ( K IC ), crack mouth opening displacement (CMOD), fracture energy ( G F ), modulus of elasticity ( E ), and characteristic length ( l ch ), were determined for both conventional and recycled aggregate specimens. The “work of fracture\"—by definition the formula—is the most reliable to calculate the fracture energy as the nonlinearity is related to the performance of FC.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"62 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136281870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-11DOI: 10.1186/s40069-023-00629-w
Won-Woo Kim, Jae-Heum Moon
Abstract This study evaluated the setting time, mechanical properties and microstructure of Portland cement (OPC) by adding SiO 2 nano- and micro-particles. The setting time was reduced due to the pozzolanic reaction of the nano- and micro-SiO 2 , and the compressive strength was increased through a reduction in the porosity of the microstructure. When nano- and micro-SiO 2 were used alone, micro-silica was the most effective in reduced the initial and final setting times and developing compressive strength. When two or more nano- and micro-SiO 2 were used, a micro-sized binder and a small amount of nano-silica effectively improved performance as the setting time was reduced to 50–52% of that of ordinary Portland cement (OPC). It appears that a small amount of nano-silica could reduce the setting time and increase compressive strength because it caused the pozzolanic reaction and because the nanoparticles filled the pores between the silica fume and cement, which were composed of relatively large particles. This result could also be derived from compressive strength and microstructure analysis. Cement paste containing to nano- and micro-silica increased the strength by approximately 112% compared to OPC. Because nano-binders may cause a reduction in flow due to their large specific surface area, adding chemical admixture needs to be considered during mix design. In addition, the particle size distribution must be considered when nano- and micro-materials are used because an imbalance in particle size distribution can increase the pore size in the microstructure.
{"title":"Analysis of Mechanical Properties and Microstructure of Nano- and Micro-SiO2 Materials as Cementitious Composite Binder","authors":"Won-Woo Kim, Jae-Heum Moon","doi":"10.1186/s40069-023-00629-w","DOIUrl":"https://doi.org/10.1186/s40069-023-00629-w","url":null,"abstract":"Abstract This study evaluated the setting time, mechanical properties and microstructure of Portland cement (OPC) by adding SiO 2 nano- and micro-particles. The setting time was reduced due to the pozzolanic reaction of the nano- and micro-SiO 2 , and the compressive strength was increased through a reduction in the porosity of the microstructure. When nano- and micro-SiO 2 were used alone, micro-silica was the most effective in reduced the initial and final setting times and developing compressive strength. When two or more nano- and micro-SiO 2 were used, a micro-sized binder and a small amount of nano-silica effectively improved performance as the setting time was reduced to 50–52% of that of ordinary Portland cement (OPC). It appears that a small amount of nano-silica could reduce the setting time and increase compressive strength because it caused the pozzolanic reaction and because the nanoparticles filled the pores between the silica fume and cement, which were composed of relatively large particles. This result could also be derived from compressive strength and microstructure analysis. Cement paste containing to nano- and micro-silica increased the strength by approximately 112% compared to OPC. Because nano-binders may cause a reduction in flow due to their large specific surface area, adding chemical admixture needs to be considered during mix design. In addition, the particle size distribution must be considered when nano- and micro-materials are used because an imbalance in particle size distribution can increase the pore size in the microstructure.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"51 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135043148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-08DOI: 10.1186/s40069-023-00620-5
Yanan Fu, Ying Zhang, Lei Wu
Abstract A growing number of nations and regions have printed concrete structures thanks to the application of 3D printing technology in the field of civil engineering. However, the houses built with printed concrete are mostly printed concrete wall structures with composite load-bearing walls and cast-in-place frames. This structure solely takes into account the performance of the structure under vertical loads, which does not address its ability to withstand horizontal loads. In this paper, wall specimens were designed and tested under horizontal reciprocal loads in order to investigate the structural performance of this cast-in-place border-frame printed concrete wall structure under horizontal loads. Four factors are examined in order to determine how well the cast-in-place frame printed concrete wall structure performs when subjected to horizontal loads: column longitudinal reinforcement strain, hysteresis curve, skeleton curve, and energy dissipation capacity. According to the test results, the addition of the wall increased the bearing capacity and accumulated energy dissipation of the specimen, but the increase in stiffness also caused the structural ductility to decrease. As a result, cracks were more likely to generate at the wall–column joints, so the stiffness matching between the printed concrete wall and the cast-in-place side frame needed to be further coordinated to obtain a higher ductility. It turns out that the wall sections have little impact on the seismic performance of the members.
{"title":"Experimental Study on Structural Performance of Cast-in-Place Frame Printed Concrete Wall","authors":"Yanan Fu, Ying Zhang, Lei Wu","doi":"10.1186/s40069-023-00620-5","DOIUrl":"https://doi.org/10.1186/s40069-023-00620-5","url":null,"abstract":"Abstract A growing number of nations and regions have printed concrete structures thanks to the application of 3D printing technology in the field of civil engineering. However, the houses built with printed concrete are mostly printed concrete wall structures with composite load-bearing walls and cast-in-place frames. This structure solely takes into account the performance of the structure under vertical loads, which does not address its ability to withstand horizontal loads. In this paper, wall specimens were designed and tested under horizontal reciprocal loads in order to investigate the structural performance of this cast-in-place border-frame printed concrete wall structure under horizontal loads. Four factors are examined in order to determine how well the cast-in-place frame printed concrete wall structure performs when subjected to horizontal loads: column longitudinal reinforcement strain, hysteresis curve, skeleton curve, and energy dissipation capacity. According to the test results, the addition of the wall increased the bearing capacity and accumulated energy dissipation of the specimen, but the increase in stiffness also caused the structural ductility to decrease. As a result, cracks were more likely to generate at the wall–column joints, so the stiffness matching between the printed concrete wall and the cast-in-place side frame needed to be further coordinated to obtain a higher ductility. It turns out that the wall sections have little impact on the seismic performance of the members.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":" 15","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-05DOI: 10.1186/s40069-023-00604-5
Ahmet Can Altunişik, Yunus Emrahan Akbulut, Süleyman Adanur, Murat Günaydin, Sara Mostofi, Ayman Mosallam
Abstract The past two decades have witnessed rapid advances in the use of fiber-reinforced polymer (FRP) composites in different engineering fields. Advantages such as high strength-to-weight ratio, corrosion resistance, and tailority have led to immense interest in the use of FRPs in wide spectrum repair and strengthening of structures. Despite their many advantages, FRPs are highly sensitive to high temperatures, which pose a major concern for fire potential structures such as buildings. Applying proper thermal insulation can enhance the fire performance of FRP and reduce the possible fire damage to the FRP strengthened element. This study set out to experimentally investigate the effectiveness of two insulation systems, “FIRECOAT” and “REALROCK” on fire performance of CFRP and GFRP strengthened concrete specimens. Various configurations and exposure durations were considered to evaluate the effectiveness of insulating materials. To perform the experiments, cylindrical concrete specimens were fabricated and strengthened using CFRP or GFRP. After insulating the specimens, they were exposed to a standard fire curve for two different durations of 30 and 60 min. The results indicate that less than 30 min of fire, both insulation systems can provide the required protection. During long exposure duration of 60 min, only REALROCK can provide the required thermal resistance for FRP-strengthened concrete. Within the tested materials, Fire Set 60 outperformed other insulating materials. It was observed that implementing Fire Set 60 in the innermost layer of thermal insulations has crucial importance in preventing the fire induced reductions in strength of FRP-strengthened concrete elements.
摘要过去二十年来，纤维增强聚合物(FRP)复合材料在不同工程领域的应用取得了快速发展。frp具有高强度重量比、耐腐蚀性和定制性等优点，因此人们对其在广谱修复和结构加固中的应用产生了极大的兴趣。尽管frp具有许多优点，但它对高温非常敏感，这对建筑物等潜在火灾结构构成了主要问题。采用适当的保温材料可以提高FRP的防火性能，减少FRP加固构件可能受到的火灾损害。本研究旨在实验研究两种保温系统“FIRECOAT”和“REALROCK”对CFRP和GFRP增强混凝土试件防火性能的影响。考虑了不同的结构和暴露时间来评估绝缘材料的有效性。为了进行试验，圆柱形混凝土试件采用CFRP或GFRP加固。绝缘后，试样暴露在标准火灾曲线中30和60分钟。结果表明，在30分钟的火灾中，两种绝缘系统都能提供所需的保护。在长达60分钟的暴露时间内，只有REALROCK才能提供frp增强混凝土所需的热阻。在测试材料中，Fire Set 60的性能优于其他绝缘材料。结果表明，在保温层最内层实施Fire Set 60对于防止火灾导致frp增强混凝土构件强度降低至关重要。
{"title":"Experimental Study of the Effect of Different Insulation Schemes on Fire Performance of FRP Strengthened Concrete: FIRECOAT and REALROCK","authors":"Ahmet Can Altunişik, Yunus Emrahan Akbulut, Süleyman Adanur, Murat Günaydin, Sara Mostofi, Ayman Mosallam","doi":"10.1186/s40069-023-00604-5","DOIUrl":"https://doi.org/10.1186/s40069-023-00604-5","url":null,"abstract":"Abstract The past two decades have witnessed rapid advances in the use of fiber-reinforced polymer (FRP) composites in different engineering fields. Advantages such as high strength-to-weight ratio, corrosion resistance, and tailority have led to immense interest in the use of FRPs in wide spectrum repair and strengthening of structures. Despite their many advantages, FRPs are highly sensitive to high temperatures, which pose a major concern for fire potential structures such as buildings. Applying proper thermal insulation can enhance the fire performance of FRP and reduce the possible fire damage to the FRP strengthened element. This study set out to experimentally investigate the effectiveness of two insulation systems, “FIRECOAT” and “REALROCK” on fire performance of CFRP and GFRP strengthened concrete specimens. Various configurations and exposure durations were considered to evaluate the effectiveness of insulating materials. To perform the experiments, cylindrical concrete specimens were fabricated and strengthened using CFRP or GFRP. After insulating the specimens, they were exposed to a standard fire curve for two different durations of 30 and 60 min. The results indicate that less than 30 min of fire, both insulation systems can provide the required protection. During long exposure duration of 60 min, only REALROCK can provide the required thermal resistance for FRP-strengthened concrete. Within the tested materials, Fire Set 60 outperformed other insulating materials. It was observed that implementing Fire Set 60 in the innermost layer of thermal insulations has crucial importance in preventing the fire induced reductions in strength of FRP-strengthened concrete elements.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"119 17","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135724529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-03DOI: 10.1186/s40069-023-00642-z
Shuwen Deng, Banfu Yan, Lian Shen, Mingxin Qin, Yina Jia
Abstract Accelerated bridge construction (ABC) has many advantages for bridge construction in modern society. While for ABC, the post-cast joint is always the weakest and most critical part. This paper presents a UHPC rhombus-strip-shaped (RSS) joint suitable for ABC. Several model tests were carried out to verify its resistance to flexural and shear. First, large-scale model tests are advanced to confirm its flexural properties. The results show that densified and welded joint interface rebars can significantly improve the ultimate bearing capacity and durability-based cracking stress of the RSS joint beams, and the ultimate bearing capacity can reach 90% of the complete beam. Then the shear-resistance tests were carried out. The results show that the UHPC RSS joint beam has excellent bending-shear mechanical properties and better ductility. Lastly, the ultimate flexural bearing capacity and shear-resistance capacity calculation methods were obtained.
{"title":"Study on Flexural and Shear Behavior of UHPC Rhombus-Strip-Shaped Joint","authors":"Shuwen Deng, Banfu Yan, Lian Shen, Mingxin Qin, Yina Jia","doi":"10.1186/s40069-023-00642-z","DOIUrl":"https://doi.org/10.1186/s40069-023-00642-z","url":null,"abstract":"Abstract Accelerated bridge construction (ABC) has many advantages for bridge construction in modern society. While for ABC, the post-cast joint is always the weakest and most critical part. This paper presents a UHPC rhombus-strip-shaped (RSS) joint suitable for ABC. Several model tests were carried out to verify its resistance to flexural and shear. First, large-scale model tests are advanced to confirm its flexural properties. The results show that densified and welded joint interface rebars can significantly improve the ultimate bearing capacity and durability-based cracking stress of the RSS joint beams, and the ultimate bearing capacity can reach 90% of the complete beam. Then the shear-resistance tests were carried out. The results show that the UHPC RSS joint beam has excellent bending-shear mechanical properties and better ductility. Lastly, the ultimate flexural bearing capacity and shear-resistance capacity calculation methods were obtained.","PeriodicalId":13832,"journal":{"name":"International Journal of Concrete Structures and Materials","volume":"122 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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