Guoyang Lu, Rui Li, Gaoyang Li, Z. Leng, Haopeng Wang
Using polyurethane (PU) modified asphalt for paving purposes has recently gained increasing interest in both academia and industry. This study aims to characterize the engineering performance of the asphalt mixture modified with one-component PU and explore its adhesive mechanism. To achieve this objective, PU modified bitumen and asphalt mixture of two different PU contents (10% and 30%) were prepared. Various laboratory material property tests, such as rotational viscosity test of binder, Marshall test, indirect tensile strength test, Hamburg wheel-tracking test, moisture susceptibility, and indirect tensile fatigue test of PU modified mixture, were performed. Fourier transform infrared spectroscopy test was carried out to explore the adhesive mechanism between PU-modified binder and aggregate. The results indicated that the overall performances of asphalt mixture were increased significantly by PU prepolymer, including increased Marshall stability, indirect tensile strength, and resistance to moisture damage, rutting and fatigue damage. It was found that PU prepolymer can react with the hydroxyl groups on the aggregate surface, which contributed to better performance of asphalt mixture. The findings of this study may facilitate the further practical applications of one-component PU-modified bituminous materials in the pavement industry.
{"title":"Performance Characterization of Asphalt Mixture Modified with One-component Polyurethane","authors":"Guoyang Lu, Rui Li, Gaoyang Li, Z. Leng, Haopeng Wang","doi":"10.1680/jcoma.22.00062","DOIUrl":"https://doi.org/10.1680/jcoma.22.00062","url":null,"abstract":"Using polyurethane (PU) modified asphalt for paving purposes has recently gained increasing interest in both academia and industry. This study aims to characterize the engineering performance of the asphalt mixture modified with one-component PU and explore its adhesive mechanism. To achieve this objective, PU modified bitumen and asphalt mixture of two different PU contents (10% and 30%) were prepared. Various laboratory material property tests, such as rotational viscosity test of binder, Marshall test, indirect tensile strength test, Hamburg wheel-tracking test, moisture susceptibility, and indirect tensile fatigue test of PU modified mixture, were performed. Fourier transform infrared spectroscopy test was carried out to explore the adhesive mechanism between PU-modified binder and aggregate. The results indicated that the overall performances of asphalt mixture were increased significantly by PU prepolymer, including increased Marshall stability, indirect tensile strength, and resistance to moisture damage, rutting and fatigue damage. It was found that PU prepolymer can react with the hydroxyl groups on the aggregate surface, which contributed to better performance of asphalt mixture. The findings of this study may facilitate the further practical applications of one-component PU-modified bituminous materials in the pavement industry.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"7 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85507853","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}
Electromagnetic (EM) radiation is generated naturally or artificially by weapons capable of affecting the power grid and modern electronic devices, in turn, a threat to the nation's defence, hospitals and communication systems. In this regard, the present study focused on designing and developing electromagnetic interference (EMI) shielding cement-based concrete using locally available materials. The shielding effectiveness (in dB) of conductive concrete was assessed using a newly designed and fabricated metallic testing chamber with a monopole antenna (1.46 GHz) and a vector network analyser. Maximum shielding effectiveness of 36 dB was achieved experimentally in conductive concrete with magnetite and graphite aggregates and 2% steel fibres. The conductive concrete developed has higher (around 3 times) shielding effectiveness compared to normal concrete of similar compressive strength ranges. In addition, a simulation study was carried out to predict the shielding effectiveness of the developed conductive concrete with the aid of CST microwave studio simulation software and validated with experimental results. Further, the durability of the conductive concrete was assessed and observed to have low permeability and porosity. The research outcome of this study will contribute as a stepping stone toward the design and development of conductive concrete against electromagnetic interference.
{"title":"Experimental and numerical investigation on conductive concrete for Electromagnetic pulse shielding","authors":"Nabodyuti Das, Ajay Singh Mahadela, Prakash Nanthagopalan, Gyanendra Verma","doi":"10.1680/jcoma.22.00041","DOIUrl":"https://doi.org/10.1680/jcoma.22.00041","url":null,"abstract":"Electromagnetic (EM) radiation is generated naturally or artificially by weapons capable of affecting the power grid and modern electronic devices, in turn, a threat to the nation's defence, hospitals and communication systems. In this regard, the present study focused on designing and developing electromagnetic interference (EMI) shielding cement-based concrete using locally available materials. The shielding effectiveness (in dB) of conductive concrete was assessed using a newly designed and fabricated metallic testing chamber with a monopole antenna (1.46 GHz) and a vector network analyser. Maximum shielding effectiveness of 36 dB was achieved experimentally in conductive concrete with magnetite and graphite aggregates and 2% steel fibres. The conductive concrete developed has higher (around 3 times) shielding effectiveness compared to normal concrete of similar compressive strength ranges. In addition, a simulation study was carried out to predict the shielding effectiveness of the developed conductive concrete with the aid of CST microwave studio simulation software and validated with experimental results. Further, the durability of the conductive concrete was assessed and observed to have low permeability and porosity. The research outcome of this study will contribute as a stepping stone toward the design and development of conductive concrete against electromagnetic interference.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"448 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80122299","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}
A. Ramachandran, Mohamed Ghalib, N. Dhami, D. Cheema, A. Mukherjee
To achieve the sustainability goals, Australia must dramatically reduce use of cement for stabilisation of soil used in road bases. Bio-based binders for soil stabilization are potential alternatives. Biocementation through Microbially Induced Calcite Precipitation (MICP) is well researched. Some research on biopolymeric stabilization is also available. This paper explores the synergistic effect of combined biopolymer and biocement for the stabilization of sandy soil and road bases. The soil has been stabilised using both biopolymer xanthan gum and MICP. The synergy between biopolymer and MICP has been evaluated by giving a few samples a combined treatment. The performance has been evaluated by compressive strength tests, micrographic analysis and water absorption. Although biopolymer treatment improved the compressive strength it degraded significantly in presence of water. Relatively high water absorption of xanthan gum could be mitigated by MICP. The study demonstrates that MICP surface coating is a sustainable solution to overcome this limitation of biopolymer. Likewise, the addition of biopolymers reduces the release of ammonia from MICP. The present study unravels the potential of a composite bio-treatment for stabilisation of road bases.
{"title":"Multi-functional Performance of Biopolymers and Biocement in Stabilisation of Soil for Road Bases","authors":"A. Ramachandran, Mohamed Ghalib, N. Dhami, D. Cheema, A. Mukherjee","doi":"10.1680/jcoma.21.00063","DOIUrl":"https://doi.org/10.1680/jcoma.21.00063","url":null,"abstract":"To achieve the sustainability goals, Australia must dramatically reduce use of cement for stabilisation of soil used in road bases. Bio-based binders for soil stabilization are potential alternatives. Biocementation through Microbially Induced Calcite Precipitation (MICP) is well researched. Some research on biopolymeric stabilization is also available. This paper explores the synergistic effect of combined biopolymer and biocement for the stabilization of sandy soil and road bases. The soil has been stabilised using both biopolymer xanthan gum and MICP. The synergy between biopolymer and MICP has been evaluated by giving a few samples a combined treatment. The performance has been evaluated by compressive strength tests, micrographic analysis and water absorption. Although biopolymer treatment improved the compressive strength it degraded significantly in presence of water. Relatively high water absorption of xanthan gum could be mitigated by MICP. The study demonstrates that MICP surface coating is a sustainable solution to overcome this limitation of biopolymer. Likewise, the addition of biopolymers reduces the release of ammonia from MICP. The present study unravels the potential of a composite bio-treatment for stabilisation of road bases.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"37 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74762258","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}
Recent thermal effect reports have shown a widespread increase in temperature associated with global warming. The need to preserve building indoors at a temperature steady with a comfortable state has become a major task for engineers. This results in development of new materials, Phase Change Material (PCM), which can be positioned in the interior of the building components to absorb the heat from the surroundings. The main aim of this work is to examine the physical, mechanical, and thermal properties of cement mortar incorporated with encapsulated PCM at different temperature phases. The materials required for PCM and encapsulation were selected based on the economy, availability, and temperature tolerance levels. Results were compared with the control specimen and showed improved behavior in thermal resistance. Compressive strength was reduced with an increased percentage of PCM, and the reduction in strength can be compensated by the addition of admixture, micro-silica. Temperature phases do not have much influence on strength and durability properties. Based on thermal resistance and strength properties 5% PCM incorporation showed best performance. Analytical model using COMSOL Multiphysics was developed to assess the thermal comfort in a building made of PCM incorporated mortar block walls and compared with conventional brick wall.
{"title":"Encapsulated Phase Change Material on Performance of Cement Mortar at Varied Temperature","authors":"Pranitha Palampalli, A. Raj, K. M. Mini","doi":"10.1680/jcoma.21.00022","DOIUrl":"https://doi.org/10.1680/jcoma.21.00022","url":null,"abstract":"Recent thermal effect reports have shown a widespread increase in temperature associated with global warming. The need to preserve building indoors at a temperature steady with a comfortable state has become a major task for engineers. This results in development of new materials, Phase Change Material (PCM), which can be positioned in the interior of the building components to absorb the heat from the surroundings. The main aim of this work is to examine the physical, mechanical, and thermal properties of cement mortar incorporated with encapsulated PCM at different temperature phases. The materials required for PCM and encapsulation were selected based on the economy, availability, and temperature tolerance levels. Results were compared with the control specimen and showed improved behavior in thermal resistance. Compressive strength was reduced with an increased percentage of PCM, and the reduction in strength can be compensated by the addition of admixture, micro-silica. Temperature phases do not have much influence on strength and durability properties. Based on thermal resistance and strength properties 5% PCM incorporation showed best performance. Analytical model using COMSOL Multiphysics was developed to assess the thermal comfort in a building made of PCM incorporated mortar block walls and compared with conventional brick wall.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"125 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77194492","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}
The São João das Areias and Criz II bridges, located in the reservoir of Aguieira Dam, in the centre of Portugal, were affected by internal swelling reactions of concrete, which particularly affected their piers and foundations. Laboratory tests diagnosed both Alkali-Aggregate Reaction and Delayed Ettringite Formation as the causes of those expansions. This situation motivated important rehabilitation works on the piers and foundations of both bridges. These rehabilitation works was based on the construction of six piles around the footing of every pier founded on the riverbed. The corresponding pile cap was connected to the emersed part of the pier. In the course of these works, a structural health monitoring system was installed in each of these bridges in order to characterize the structural effects of the swelling reactions, both in the loss of rigidity and the temporal evolution of this degradation. The aim of this paper is to describe the instrumentation performed in these bridges and present the preliminary results achieved.
位于葡萄牙中部Aguieira大坝水库的 o jo达斯阿雷亚斯桥和Criz II桥受到混凝土内部膨胀反应的影响，特别是对桥墩和基础的影响。实验室测试诊断碱集料反应和延迟钙矾石形成是这些膨胀的原因。这种情况促使对两座桥梁的桥墩和基础进行重要的修复工作。这些修复工程的基础是在河床上建立的每个桥墩的基础周围建造六个桩。相应的桩帽与墩的露出部分相连。在这些工程的过程中，每座桥梁都安装了结构健康监测系统，以表征膨胀反应对结构的影响，包括刚度的丧失和这种退化的时间演变。本文的目的是描述在这些桥梁中进行的仪器，并介绍取得的初步结果。
{"title":"Monitoring the structural effects of internal swelling reactions in Aguieira bridges","authors":"L. O. Santos, Min Xu, A. Silva","doi":"10.1680/jcoma.21.00046","DOIUrl":"https://doi.org/10.1680/jcoma.21.00046","url":null,"abstract":"The São João das Areias and Criz II bridges, located in the reservoir of Aguieira Dam, in the centre of Portugal, were affected by internal swelling reactions of concrete, which particularly affected their piers and foundations. Laboratory tests diagnosed both Alkali-Aggregate Reaction and Delayed Ettringite Formation as the causes of those expansions. This situation motivated important rehabilitation works on the piers and foundations of both bridges. These rehabilitation works was based on the construction of six piles around the footing of every pier founded on the riverbed. The corresponding pile cap was connected to the emersed part of the pier. In the course of these works, a structural health monitoring system was installed in each of these bridges in order to characterize the structural effects of the swelling reactions, both in the loss of rigidity and the temporal evolution of this degradation. The aim of this paper is to describe the instrumentation performed in these bridges and present the preliminary results achieved.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72703113","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}
The advantages of using self-compacting concrete (SCC) in comparison to traditional vibrated concrete are widely acknowledged. One of the key challenges in producing consistence SCC mix lies in the ability to control its performance both in fresh and hardened states. There are several methodologies currently used for mix proportion design of SCC to achieve better quality and strength. This paper investigates the consistency of a plastic-viscosity based mix proportioning method by exploring the fresh state flow properties and hardened state compressive strengths of SCC mix produced using Portland limestone cement (PLC). For this purpose, SCC design mixes with target compressive strengths between 30 MPa and 70 MPa are tested. It was revealed that while using the chosen PLC type, the mix proportioning method which is based on the estimation of plastic-viscosity failed to achieve the predicted compressive strength in the case of target mix strength 60MPa and above. This paper aims to propose a procedure to mitigate this discrepancy by demonstrating that the quality and performance of the self-compacting concrete produced using plastic-viscosity based mixed design can be influenced by the cement type used and this can also affect the target compressive strength achieved by the concrete mix.
{"title":"Plastic-viscosity based mix design and the effect of limestone powder on material performance of self-compacting concrete","authors":"A. Mimoun, S. Kulasegaram","doi":"10.1680/jcoma.21.00038","DOIUrl":"https://doi.org/10.1680/jcoma.21.00038","url":null,"abstract":"The advantages of using self-compacting concrete (SCC) in comparison to traditional vibrated concrete are widely acknowledged. One of the key challenges in producing consistence SCC mix lies in the ability to control its performance both in fresh and hardened states. There are several methodologies currently used for mix proportion design of SCC to achieve better quality and strength. This paper investigates the consistency of a plastic-viscosity based mix proportioning method by exploring the fresh state flow properties and hardened state compressive strengths of SCC mix produced using Portland limestone cement (PLC). For this purpose, SCC design mixes with target compressive strengths between 30 MPa and 70 MPa are tested. It was revealed that while using the chosen PLC type, the mix proportioning method which is based on the estimation of plastic-viscosity failed to achieve the predicted compressive strength in the case of target mix strength 60MPa and above. This paper aims to propose a procedure to mitigate this discrepancy by demonstrating that the quality and performance of the self-compacting concrete produced using plastic-viscosity based mixed design can be influenced by the cement type used and this can also affect the target compressive strength achieved by the concrete mix.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"22 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72878740","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}
Nowadays, Alkali-Aggregate Reaction (AAR) in concrete causes serious concerns for the operation and the integrity of many mass and reinforced concrete structures, basically for hydraulic structures (dams, powerhouses, etc.) and any other concrete structure that is exposed to moisture. It is recognized that the kinetic of AAR is greatly driven by the temperature and the moisture amongst other parameters and the induced strain is assumed to be oriented according to the stress state. Due to complexity of AAR and its multi-physical nature, the use of chemomechanical modelling is very helpful for making predictions in terms of displacements and concrete damage. Moreover, the macro modelling approaches are frequently preferred to perform engineering work for real structures. In this context, this paper presents the implementation of a chemomechanical model of AAR for concrete in Abaqus Explicit. With this approach, AAR effects are introduced via the VUEXPAN user-subroutine jointly with the Concrete Damage Plasticity (CDP) model of Abaqus. The Abaqus explicit solver is chosen as it deals effectively with very large finite element models simulating highly nonlinear deformation due to AAR. The verification of the proposed model is performed at the material level. Moreover, it is presented a case study regarding real hydraulic structure affected by AAR located in North America.
{"title":"Finite-element modelling of alkali−aggregate reaction in a concrete hydraulic structure","authors":"A. Nour, A. Cherfaoui","doi":"10.1680/jcoma.21.00057","DOIUrl":"https://doi.org/10.1680/jcoma.21.00057","url":null,"abstract":"Nowadays, Alkali-Aggregate Reaction (AAR) in concrete causes serious concerns for the operation and the integrity of many mass and reinforced concrete structures, basically for hydraulic structures (dams, powerhouses, etc.) and any other concrete structure that is exposed to moisture. It is recognized that the kinetic of AAR is greatly driven by the temperature and the moisture amongst other parameters and the induced strain is assumed to be oriented according to the stress state. Due to complexity of AAR and its multi-physical nature, the use of chemomechanical modelling is very helpful for making predictions in terms of displacements and concrete damage. Moreover, the macro modelling approaches are frequently preferred to perform engineering work for real structures. In this context, this paper presents the implementation of a chemomechanical model of AAR for concrete in Abaqus Explicit. With this approach, AAR effects are introduced via the VUEXPAN user-subroutine jointly with the Concrete Damage Plasticity (CDP) model of Abaqus. The Abaqus explicit solver is chosen as it deals effectively with very large finite element models simulating highly nonlinear deformation due to AAR. The verification of the proposed model is performed at the material level. Moreover, it is presented a case study regarding real hydraulic structure affected by AAR located in North America.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"10 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87619947","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}
Gabriel Zat Guizzardi, Marinara da Silva Machado, W. Michelon, D. F. Vanin
As the construction industry is always in seek of stronger and more sustainable materials, the use of natural fibres as a reinforcement agent has been considered, for both enhancement of mechanical properties and decreasing carbon footprint. Specifically, sisal fibres (agave sisalana) present a tensile strength up to 880 MPa, as having cellulose as the main constituent. Hence, the addition of varying lengths and fibre concentrations have been explored as reinforcements in cement paste. A composite mechanic's approach has been applied to estimate the minimum volume fraction and fibre's critical length, which was further characterized by water uptake, as it directly influences cement consistency. Furthermore, the flexural modulus of rupture (MOR) and compressive strength were also assessed. It was found that 1.0% (vol.%) of 20 mm length could increase the MOR up to 150.71% while giving up almost 25% in compressive strength. On the other hand, 0.5% (vol. %) of 5 mm length reached a 103.42% increase in the MOR while reducing only 7.25% in compressive strength. Therefore, it was concluded that shorter fibres were beneficial concerning mechanical performance. Ultimately, some sort of fibre treatment is suggested to avoid water absorption, which can affect the overall workability of fresh cement paste, and long-term durability aspects such as alkaline hydrolysis and mineralization.
{"title":"On the mechanical behaviour of natural sisal fibre reinforced cement paste","authors":"Gabriel Zat Guizzardi, Marinara da Silva Machado, W. Michelon, D. F. Vanin","doi":"10.1680/jcoma.21.00007","DOIUrl":"https://doi.org/10.1680/jcoma.21.00007","url":null,"abstract":"As the construction industry is always in seek of stronger and more sustainable materials, the use of natural fibres as a reinforcement agent has been considered, for both enhancement of mechanical properties and decreasing carbon footprint. Specifically, sisal fibres (agave sisalana) present a tensile strength up to 880 MPa, as having cellulose as the main constituent. Hence, the addition of varying lengths and fibre concentrations have been explored as reinforcements in cement paste. A composite mechanic's approach has been applied to estimate the minimum volume fraction and fibre's critical length, which was further characterized by water uptake, as it directly influences cement consistency. Furthermore, the flexural modulus of rupture (MOR) and compressive strength were also assessed. It was found that 1.0% (vol.%) of 20 mm length could increase the MOR up to 150.71% while giving up almost 25% in compressive strength. On the other hand, 0.5% (vol. %) of 5 mm length reached a 103.42% increase in the MOR while reducing only 7.25% in compressive strength. Therefore, it was concluded that shorter fibres were beneficial concerning mechanical performance. Ultimately, some sort of fibre treatment is suggested to avoid water absorption, which can affect the overall workability of fresh cement paste, and long-term durability aspects such as alkaline hydrolysis and mineralization.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"77 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81707217","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}
This paper studies the mechanical properties of polymer concrete (PC) with three types of resin systems. First, the effect of 0.5 wt% up to 3 wt% basalt fiber on the mechanical properties of a quaternary epoxy-based PC is investigated experimentally, and the best weight percentage of basalt fiber is obtained. The results show that adding basalt fiber to PC caused the greatest enhancement within 10% in compressive strength, 10% in flexural strength, 35% in the splitting tensile strength, and 315% in impact strength. In the next step, the effect of nanoclay particles on the mechanical properties of basalt fiber-reinforced PC (BFRPC) is analyzed experimentally. Nanoclays increase the compressive strength up to 7%, flexural strength up to 27%, and impact strength up to 260% but decrease the tensile strength of the PC. Field-emission scanning electron microscopy (FESEM) analysis is performed to study the fracture surface and morphology of various concrete specimens. In the last step, we consider the effect of two other different resin systems, rigid polyurethane and rigid polyurethane foam on the mechanical properties of reinforced polymer concrete. A comparison study presents that the epoxy PC has a higher specific strength than the polyurethane and ultra-lightweight polyurethane foam PC.
{"title":"Mechanical Properties of Reinforced Polymer Concrete with Three Types of Resin Systems","authors":"M. H. Niaki, M. Ahangari, A. Fereidoon","doi":"10.1680/jcoma.21.00060","DOIUrl":"https://doi.org/10.1680/jcoma.21.00060","url":null,"abstract":"This paper studies the mechanical properties of polymer concrete (PC) with three types of resin systems. First, the effect of 0.5 wt% up to 3 wt% basalt fiber on the mechanical properties of a quaternary epoxy-based PC is investigated experimentally, and the best weight percentage of basalt fiber is obtained. The results show that adding basalt fiber to PC caused the greatest enhancement within 10% in compressive strength, 10% in flexural strength, 35% in the splitting tensile strength, and 315% in impact strength. In the next step, the effect of nanoclay particles on the mechanical properties of basalt fiber-reinforced PC (BFRPC) is analyzed experimentally. Nanoclays increase the compressive strength up to 7%, flexural strength up to 27%, and impact strength up to 260% but decrease the tensile strength of the PC. Field-emission scanning electron microscopy (FESEM) analysis is performed to study the fracture surface and morphology of various concrete specimens. In the last step, we consider the effect of two other different resin systems, rigid polyurethane and rigid polyurethane foam on the mechanical properties of reinforced polymer concrete. A comparison study presents that the epoxy PC has a higher specific strength than the polyurethane and ultra-lightweight polyurethane foam PC.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"59 4 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78551939","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}
The impact of high-alkali Portland cements on the prescribed level of supplementary cementitious materials required in the Canadian standard for akali-silica reaction mitigation was evaluated. Based on the results, for concretes containing aggregates exhibiting moderate reactivity, the maximum allowable cement alkali limit was raised from 1.00% to 1.15%. For all levels of aggregate reactivity, cement alkali contents could be allowed up to 1.25% provided the recommended level of mitigation by supplementary cementitious materials was increased. In the initial laboratory study, mortar bars and concrete prisms were cast and monitored using two different reactive aggregates and recommended levels of fly ash and slag. For the concrete prism tests, the alkali contents of the cements were increased to 1.25%, as per the standard, or were increased by 0.25%. Instrumented outdoor exposure concrete blocks, along with additional concrete prisms stored at different temperatures, were cast from numerous mixtures made with cement alkali equivalents ranging up to 1.22%. This paper report on the long-term performance of the prisms and concrete blocks after 12 and 27 years. The performance of the outdoor blocks is also compared to predicted performance based on the accelerated mortar bar and concrete prism test results.
{"title":"Long-term alkali-silica mitigation of high-alkali concrete with cement replacements","authors":"D. Hooton, B. Fournier","doi":"10.1680/jcoma.21.00049","DOIUrl":"https://doi.org/10.1680/jcoma.21.00049","url":null,"abstract":"The impact of high-alkali Portland cements on the prescribed level of supplementary cementitious materials required in the Canadian standard for akali-silica reaction mitigation was evaluated. Based on the results, for concretes containing aggregates exhibiting moderate reactivity, the maximum allowable cement alkali limit was raised from 1.00% to 1.15%. For all levels of aggregate reactivity, cement alkali contents could be allowed up to 1.25% provided the recommended level of mitigation by supplementary cementitious materials was increased. In the initial laboratory study, mortar bars and concrete prisms were cast and monitored using two different reactive aggregates and recommended levels of fly ash and slag. For the concrete prism tests, the alkali contents of the cements were increased to 1.25%, as per the standard, or were increased by 0.25%. Instrumented outdoor exposure concrete blocks, along with additional concrete prisms stored at different temperatures, were cast from numerous mixtures made with cement alkali equivalents ranging up to 1.22%. This paper report on the long-term performance of the prisms and concrete blocks after 12 and 27 years. The performance of the outdoor blocks is also compared to predicted performance based on the accelerated mortar bar and concrete prism test results.","PeriodicalId":51787,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Construction Materials","volume":"69 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89515290","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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