Depending on the type of application, polymer concrete (PC) may be exposed to high temperatures. Therefore, it is important to investigate the influence of exposure to elevated temperatures on the fracture mechanics of PC. For this purpose, the PC composed of epoxy as resin, silica sand and crushed basalt as aggregates, and nanoclay as nanofiller is synthesized. The prepared PC is exposed to temperatures of 24, 40, 60, 80, 100, 120, and 140°C for two hours, and the residual fracture toughness and fracture energy in mode I and mode II are studied. Three-point bending test is conducted on cracked semi-circular bend specimens with the crack angle of 0° (pure mode I) and 41° (pure mode II) to determine the fracture parameters. Subjecting to high temperatures significantly increased the fracture toughness and fracture energy of the PC. The maximum fracture toughness and fracture energy are obtained after exposure to 120°C and 140°C, respectively. Scanning electron microscope (SEM) micrographs are used to investigate the fracture surface of the PC. The results of the present experimental research are useful in understanding the fracture mechanics behavior of PCs in mode I and mode II after being subjected to high temperatures.
{"title":"Influence of elevated temperatures on mode I and mode II fracture toughness and fracture energy of nanoclay reinforced polymer concrete","authors":"Ali Abdi Aghdam, Mostafa Hassani Niaki","doi":"10.1680/jmacr.23.00163","DOIUrl":"https://doi.org/10.1680/jmacr.23.00163","url":null,"abstract":"Depending on the type of application, polymer concrete (PC) may be exposed to high temperatures. Therefore, it is important to investigate the influence of exposure to elevated temperatures on the fracture mechanics of PC. For this purpose, the PC composed of epoxy as resin, silica sand and crushed basalt as aggregates, and nanoclay as nanofiller is synthesized. The prepared PC is exposed to temperatures of 24, 40, 60, 80, 100, 120, and 140°C for two hours, and the residual fracture toughness and fracture energy in mode I and mode II are studied. Three-point bending test is conducted on cracked semi-circular bend specimens with the crack angle of 0° (pure mode I) and 41° (pure mode II) to determine the fracture parameters. Subjecting to high temperatures significantly increased the fracture toughness and fracture energy of the PC. The maximum fracture toughness and fracture energy are obtained after exposure to 120°C and 140°C, respectively. Scanning electron microscope (SEM) micrographs are used to investigate the fracture surface of the PC. The results of the present experimental research are useful in understanding the fracture mechanics behavior of PCs in mode I and mode II after being subjected to high temperatures.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138493759","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}
Zhiyou Jia, José Aguiar, Sandra Cunha, Carlos Jesus, Fernando Castro
As the economy and industrialization have grown, the foundry industry has produced a significant amount of ceramic mold casting waste (CMCW). To promote resource utilization, this study investigates recycling CMCW as a partial replacement for lightweight aggregates in lightweight concrete. This study investigated the durability of lightweight concrete mixes with varying CMCW content, using surface electrical tests, ultrasonic pulse velocity measurements, non-steady state accelerated chloride penetration tests, and carbonation resistance experiments. Then, the results indicate that a lightweight concrete containing 80% CMCW exhibited greater density and uniformity, greater resistance to chloride ion penetration and better resistance to carbonation. These findings suggest that CMCW can be an effective and sustainable replacement for lightweight aggregate in lightweight concrete, improving their durability and environmental performance. This research contributes to the development of sustainable construction materials and provides insights for the use of CMCW in the foundry industry.
{"title":"Durability properties of lightweight concrete with ceramic mold casting waste","authors":"Zhiyou Jia, José Aguiar, Sandra Cunha, Carlos Jesus, Fernando Castro","doi":"10.1680/jmacr.23.00125","DOIUrl":"https://doi.org/10.1680/jmacr.23.00125","url":null,"abstract":"As the economy and industrialization have grown, the foundry industry has produced a significant amount of ceramic mold casting waste (CMCW). To promote resource utilization, this study investigates recycling CMCW as a partial replacement for lightweight aggregates in lightweight concrete. This study investigated the durability of lightweight concrete mixes with varying CMCW content, using surface electrical tests, ultrasonic pulse velocity measurements, non-steady state accelerated chloride penetration tests, and carbonation resistance experiments. Then, the results indicate that a lightweight concrete containing 80% CMCW exhibited greater density and uniformity, greater resistance to chloride ion penetration and better resistance to carbonation. These findings suggest that CMCW can be an effective and sustainable replacement for lightweight aggregate in lightweight concrete, improving their durability and environmental performance. This research contributes to the development of sustainable construction materials and provides insights for the use of CMCW in the foundry industry.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504820","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}
The amount of industrial waste is increasing along with industrial production. Therefore, reusing or recycling these harmful wastes is quite a significant issue for waste management. Concrete, the most widely used material in the world, is a suitable place to use these wastes. This study used grinding swarf, which had not been used in cementitious composites before, and metal shaving from the CNC milling process. The effects of these wastes on the strength and durability of cement mortars were investigated by using them separately and in hybrid forms. Flowability, fresh unit weight, compressive strength, flexural strength, water absorption, and high-temperature effect tests were conducted on mortar samples. Although the wastes contributed when used alone, they yielded the highest contribution when combined. When the waste materials were used in a hybrid form, they increased compressive strength, flexural strength, and high-temperature resistance by 29%, 12.98%, and 49.50%, respectively. Metal shavings showed fiber effects, and grinding swarfs improved the strength and durability properties owing to their physical and chemical composition.
{"title":"Effects of hybrid metallic wastes on the strength and durability properties of cementitious mortars","authors":"Musa Yildirim, Hacer Bilir Özhan","doi":"10.1680/jmacr.23.00122","DOIUrl":"https://doi.org/10.1680/jmacr.23.00122","url":null,"abstract":"The amount of industrial waste is increasing along with industrial production. Therefore, reusing or recycling these harmful wastes is quite a significant issue for waste management. Concrete, the most widely used material in the world, is a suitable place to use these wastes. This study used grinding swarf, which had not been used in cementitious composites before, and metal shaving from the CNC milling process. The effects of these wastes on the strength and durability of cement mortars were investigated by using them separately and in hybrid forms. Flowability, fresh unit weight, compressive strength, flexural strength, water absorption, and high-temperature effect tests were conducted on mortar samples. Although the wastes contributed when used alone, they yielded the highest contribution when combined. When the waste materials were used in a hybrid form, they increased compressive strength, flexural strength, and high-temperature resistance by 29%, 12.98%, and 49.50%, respectively. Metal shavings showed fiber effects, and grinding swarfs improved the strength and durability properties owing to their physical and chemical composition.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504817","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}
Recycled aggregate concrete (RAC) often shows different strength and deformation properties to natural aggregate concrete (NAC) and may therefore have an impact on the connections between precast concrete elements. In this work, three simple connections between precast concrete columns were considered, including a wet connection with bedding mortar, a dry connection without bedding mortar and a monolithic joint with plain concrete. An industrially produced coarse recycled concrete aggregate (RCA) was used to replace partially or fully a coarse natural aggregate in the concrete. A total of twenty-two 200 mm × 200 mm × 500 mm reinforced concrete columns were prepared and tested under axial monotonic loading through displacement control. The results showed that regardless of RCA content, the equation specified in ACI 318 (2019) and the one proposed by Vambersky (1990) provided safe estimates of the load-bearing capacity of wet connections between reinforced RAC columns.
再生骨料混凝土(RAC)往往表现出与天然骨料混凝土(NAC)不同的强度和变形特性，因此可能对预制混凝土构件之间的连接产生影响。在这项工作中，考虑了预制混凝土柱之间的三种简单连接，包括带衬垫砂浆的湿连接，不带衬垫砂浆的干连接以及与素混凝土的整体连接。采用工业生产的粗再生混凝土骨料(RCA)部分或全部替代混凝土中的粗天然骨料。通过位移控制，制备了22根200 mm × 200 mm × 500 mm钢筋混凝土柱，并进行了轴向单调加载试验。结果表明，无论RCA含量如何，ACI 318(2019)中规定的方程和Vambersky(1990)提出的方程都提供了钢筋RAC柱间湿连接承载能力的安全估计。
{"title":"Load-bearing capacity of precast high-strength self-compacting recycled aggregate concrete column-to-column connections","authors":"Xiaoguang Chen, Zeger Sierens, Jiabin Li","doi":"10.1680/jmacr.23.00109","DOIUrl":"https://doi.org/10.1680/jmacr.23.00109","url":null,"abstract":"Recycled aggregate concrete (RAC) often shows different strength and deformation properties to natural aggregate concrete (NAC) and may therefore have an impact on the connections between precast concrete elements. In this work, three simple connections between precast concrete columns were considered, including a wet connection with bedding mortar, a dry connection without bedding mortar and a monolithic joint with plain concrete. An industrially produced coarse recycled concrete aggregate (RCA) was used to replace partially or fully a coarse natural aggregate in the concrete. A total of twenty-two 200 mm × 200 mm × 500 mm reinforced concrete columns were prepared and tested under axial monotonic loading through displacement control. The results showed that regardless of RCA content, the equation specified in ACI 318 (2019) and the one proposed by Vambersky (1990) provided safe estimates of the load-bearing capacity of wet connections between reinforced RAC columns.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504818","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}
Improving the flexural strength of a chopped-carbon fibre-reinforced cement-based composite while promoting good workability is highly attractive for building high-rise large-span structures. This study utilized a sulphoaluminate-based expansive agent to optimize the mechanical properties of chopped-carbon fibre-reinforced cement-based composites by improving the fibre–matrix interfacial properties. The results of a single-fibre pull-out test showed that the interfacial frictional bond strength improved up to 51% owing to the addition of the expansive agent, whereas the chemical debonding energy remained nearly unchanged. The study then investigated the effects of various concentrations of the expansive agent on the strength of the cement paste containing various lengths and volume fractions of the carbon fibre. The results indicated that benefited from the expansive agent induced high interfacial bond strength, the flexural strength and fluidity of the carbon fibre reinforced cement paste could be further optimized. For example, by utilizing expansive agent, the flexural strength could be further improved by 28% for cement paste containing 0.5% carbon fibre with length of 15mm.
{"title":"Effect of an expansive agent on the interfacial bond and mechanical properties of carbon fibre-reinforced cement-based composites","authors":"Jinghui Dai, Jun Wang, Huigang Xiao","doi":"10.1680/jmacr.23.00098","DOIUrl":"https://doi.org/10.1680/jmacr.23.00098","url":null,"abstract":"Improving the flexural strength of a chopped-carbon fibre-reinforced cement-based composite while promoting good workability is highly attractive for building high-rise large-span structures. This study utilized a sulphoaluminate-based expansive agent to optimize the mechanical properties of chopped-carbon fibre-reinforced cement-based composites by improving the fibre–matrix interfacial properties. The results of a single-fibre pull-out test showed that the interfacial frictional bond strength improved up to 51% owing to the addition of the expansive agent, whereas the chemical debonding energy remained nearly unchanged. The study then investigated the effects of various concentrations of the expansive agent on the strength of the cement paste containing various lengths and volume fractions of the carbon fibre. The results indicated that benefited from the expansive agent induced high interfacial bond strength, the flexural strength and fluidity of the carbon fibre reinforced cement paste could be further optimized. For example, by utilizing expansive agent, the flexural strength could be further improved by 28% for cement paste containing 0.5% carbon fibre with length of 15mm.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504819","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}
During pumping of concrete, the lubrication layer (LL) formed at the interface of the concrete and the pipe plays a crucial role in facilitating the process. Shear thickening in this layer affects the concrete pumping significantly. However, very few studies are available in understanding the onset and intensity of shear thickening behavior of the lubrication layer. In this study, the effect of solid volume fraction (SVF), superplasticizer (SP) dosage, supplementary cementitious materials (SCMs) and hydration on the shear thickening (Continuous and discontinuous) behavior of cementitious suspensions are investigated. Results show that an increase in SVF, reduces the shear thickening intensity in case of cement (OPC) systems whereas the intensity is amplified for systems with fly ash (FA) and ground granulated blast furnace slag (GGBS). An increment in the SP dosage results in an early onset and increases the shear thickening intensity, regardless of the binder used. GGBS based systems show the highest shear thickening intensity, followed by OPC and FA based systems. Based on the results, it is evident that the optimization of SP dosage for OPC based systems needs to be carried out based on the structural build-up, while for FA or GGBS based systems, the SP optimization needs to be carried out based on shear thickening behavior with respect to hydration.
{"title":"Shear thickening of cementitious suspensions: effect of high solid volume fraction and hydration","authors":"P. V. P. Moorthi, Prakash Nanthagopalan","doi":"10.1680/jmacr.23.00126","DOIUrl":"https://doi.org/10.1680/jmacr.23.00126","url":null,"abstract":"During pumping of concrete, the lubrication layer (LL) formed at the interface of the concrete and the pipe plays a crucial role in facilitating the process. Shear thickening in this layer affects the concrete pumping significantly. However, very few studies are available in understanding the onset and intensity of shear thickening behavior of the lubrication layer. In this study, the effect of solid volume fraction (SVF), superplasticizer (SP) dosage, supplementary cementitious materials (SCMs) and hydration on the shear thickening (Continuous and discontinuous) behavior of cementitious suspensions are investigated. Results show that an increase in SVF, reduces the shear thickening intensity in case of cement (OPC) systems whereas the intensity is amplified for systems with fly ash (FA) and ground granulated blast furnace slag (GGBS). An increment in the SP dosage results in an early onset and increases the shear thickening intensity, regardless of the binder used. GGBS based systems show the highest shear thickening intensity, followed by OPC and FA based systems. Based on the results, it is evident that the optimization of SP dosage for OPC based systems needs to be carried out based on the structural build-up, while for FA or GGBS based systems, the SP optimization needs to be carried out based on shear thickening behavior with respect to hydration.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504816","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}
Ali Dousti, Negar Saraei, Mohammad Shekarchi, Mohammad Nikookar
Microbiological attacks cause concrete structures used in wastewater collection and treatment facilities to deteriorate and degrade rapidly in short service lives. Hence, it is more cost-effective to produce concrete resistant to chemical and sulfuric acid corrosion. In the present study, a total of six concrete mixtures incorporating 7.5% silica fumes (SF) and 10% natural zeolite (ZE) were immersed in 0.5% and 1% sulfuric acid solutions with a maximum pH threshold of 2 and 1 respectively for 70 weeks to enhance concrete resistance to acid attack. The specimens were regularly monitored for surface deterioration, mass changes, and crushing load changes. To better understand the relationship between the pore structure of concrete mixtures and resistance to sulfuric acid, various durability tests such as rapid chloride penetration, water absorption, electrical resistivity, and chloride diffusion coefficient were performed. Based on the results obtained, it was concluded that converting calcium hydroxide (CH) into CSH gel through pozzolanic reactions and then refining the porosity of concrete with silica fume and natural zeolite was effective in enhancing the resistance of concrete to attack by sulfuric acid of relatively low concentration. As a result, using SF and ZE is a lower-cost method for reducing corrosion rates to extend the service life of facilities, particularly in lower concentrations.
{"title":"Increasing service life of concretes in sewage treatment plants using silica fume and natural zeolite","authors":"Ali Dousti, Negar Saraei, Mohammad Shekarchi, Mohammad Nikookar","doi":"10.1680/jmacr.23.00129","DOIUrl":"https://doi.org/10.1680/jmacr.23.00129","url":null,"abstract":"Microbiological attacks cause concrete structures used in wastewater collection and treatment facilities to deteriorate and degrade rapidly in short service lives. Hence, it is more cost-effective to produce concrete resistant to chemical and sulfuric acid corrosion. In the present study, a total of six concrete mixtures incorporating 7.5% silica fumes (SF) and 10% natural zeolite (ZE) were immersed in 0.5% and 1% sulfuric acid solutions with a maximum pH threshold of 2 and 1 respectively for 70 weeks to enhance concrete resistance to acid attack. The specimens were regularly monitored for surface deterioration, mass changes, and crushing load changes. To better understand the relationship between the pore structure of concrete mixtures and resistance to sulfuric acid, various durability tests such as rapid chloride penetration, water absorption, electrical resistivity, and chloride diffusion coefficient were performed. Based on the results obtained, it was concluded that converting calcium hydroxide (CH) into CSH gel through pozzolanic reactions and then refining the porosity of concrete with silica fume and natural zeolite was effective in enhancing the resistance of concrete to attack by sulfuric acid of relatively low concentration. As a result, using SF and ZE is a lower-cost method for reducing corrosion rates to extend the service life of facilities, particularly in lower concentrations.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504815","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}
Waqas Latif Baloch, Hocine Siad, Mohamed Lachemi, Mustafa Sahmaran
This research examines the influence of various supplementary cementitious materials (SCMs) and fibers on the fire resistance of composite systems (CS) that combine engineered cementitious composites (ECC) in tension with self-compacting concrete (SCC) in compression. The study was designed to determine the ECC formulation ideally suitable for optimizing mechanical properties and bonding performance at ambient and elevated temperatures. The SCC and ECC were hot-joined without vibration or surface preparation, using a fresh-to-fresh casting method. Modifications to the chemical composition of ECC included the addition of Class-F fly ash (FAF), Class-C fly ash (FAC), or slag (SL), as well as polyvinyl alcohol (PVA) or steel reinforcing fibers. Subsequently, the samples were exposed to temperatures of 200 °C, 400 °C, 600 °C, and 800 °C, followed by comprehensive testing to evaluate their flexural strength, tensile strength, and interfacial properties. The results indicate that the incorporation of an ECC layer within the SCC system significantly improved mechanical strength, and thermal stability, both at ambient temperatures and under high-temperature conditions. Notably, the utilization of FAF in the ECC layer offered superior thermal stability and ensured the retention of desirable residual mechanical properties compared to FAC and SL. Moreover, steel fiber reinforcement greatly improved the bonding between SCC and ECC, outperforming PVA reinforcement at elevated temperatures.
{"title":"Impact of supplementary cementitious materials and fibers in ECC on the fire resistance of hot-jointed SCC/ECC composites","authors":"Waqas Latif Baloch, Hocine Siad, Mohamed Lachemi, Mustafa Sahmaran","doi":"10.1680/jmacr.23.00023","DOIUrl":"https://doi.org/10.1680/jmacr.23.00023","url":null,"abstract":"This research examines the influence of various supplementary cementitious materials (SCMs) and fibers on the fire resistance of composite systems (CS) that combine engineered cementitious composites (ECC) in tension with self-compacting concrete (SCC) in compression. The study was designed to determine the ECC formulation ideally suitable for optimizing mechanical properties and bonding performance at ambient and elevated temperatures. The SCC and ECC were hot-joined without vibration or surface preparation, using a fresh-to-fresh casting method. Modifications to the chemical composition of ECC included the addition of Class-F fly ash (FAF), Class-C fly ash (FAC), or slag (SL), as well as polyvinyl alcohol (PVA) or steel reinforcing fibers. Subsequently, the samples were exposed to temperatures of 200 °C, 400 °C, 600 °C, and 800 °C, followed by comprehensive testing to evaluate their flexural strength, tensile strength, and interfacial properties. The results indicate that the incorporation of an ECC layer within the SCC system significantly improved mechanical strength, and thermal stability, both at ambient temperatures and under high-temperature conditions. Notably, the utilization of FAF in the ECC layer offered superior thermal stability and ensured the retention of desirable residual mechanical properties compared to FAC and SL. Moreover, steel fiber reinforcement greatly improved the bonding between SCC and ECC, outperforming PVA reinforcement at elevated temperatures.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138517460","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}
A novel lightweight aggregate concrete (LWAC) or lightweight concrete (LWC) is developed using the expanded perlite powder (EPP) and light-weight expanded clay aggregate (LECA) as a replacement for conventional fine and coarse aggregates respectively. Furthermore, the natural plant-based flax fiber in treated form was added to the LWC mix at three different volume fractions. The mechanical and thermal characterization of lightweight concrete was done using the compressive strength test, split tensile test, modulus of rupture, thermal conductivity and thermal resistance test. Moreover, the micro-structural and durability properties were obtained using scanning electron microscope/ energy dispersive X-ray spectrum analysis, rapid chloride penetration test, sorptivity and water absorption test. Test results reveal that the addition of 2.0% flax fiber resulted in improved mechanical, thermal and durability properties when compared to the LWC with no fibers. Moreover, the micro-structural analysis using SEM revealed the formation of Ettringite which is responsible for the strength development in the LWAC mix.
{"title":"Thermal and mechanical properties of a sustainable bio-flax fiber based light-weight aggregate concrete","authors":"M. Chellapandian, J. Maheswaran, N. Arunachelam","doi":"10.1680/jmacr.23.00080","DOIUrl":"https://doi.org/10.1680/jmacr.23.00080","url":null,"abstract":"A novel lightweight aggregate concrete (LWAC) or lightweight concrete (LWC) is developed using the expanded perlite powder (EPP) and light-weight expanded clay aggregate (LECA) as a replacement for conventional fine and coarse aggregates respectively. Furthermore, the natural plant-based flax fiber in treated form was added to the LWC mix at three different volume fractions. The mechanical and thermal characterization of lightweight concrete was done using the compressive strength test, split tensile test, modulus of rupture, thermal conductivity and thermal resistance test. Moreover, the micro-structural and durability properties were obtained using scanning electron microscope/ energy dispersive X-ray spectrum analysis, rapid chloride penetration test, sorptivity and water absorption test. Test results reveal that the addition of 2.0% flax fiber resulted in improved mechanical, thermal and durability properties when compared to the LWC with no fibers. Moreover, the micro-structural analysis using SEM revealed the formation of Ettringite which is responsible for the strength development in the LWAC mix.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504814","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}
Luca Lavagna, Daniel Suarez-Riera, Nicoletta Mangani, Matteo Pavese
The use of waste plastic from Waste Electrical and Electronic Equipment (WEEE) as a substitute for natural aggregate in cementitious materials is an increasingly relevant issue. In fact, this would allow to recycle plastics destined for landfills and to decrease the use of new natural resources. However, replacing sand with plastic tends to reduce the mechanical properties of mortars due to the different mechanical properties between the natural aggregate and the waste plastic and the poor interfacial compatibility between the plastic and the cement paste. This work used several strategies to improve the mechanical properties of mortars containing waste plastic. The addition of 1 % of superplasticizer coupled with a lower w/c ratio succeeds in restoring the mechanical properties to values equal to a standard mortar prepared with the natural aggregate, thus obtaining a material that can be used in the construction field.
{"title":"Mortars containing waste plastic from WEEE as replacement of natural aggregate: different strategies to achieve good mechanical properties","authors":"Luca Lavagna, Daniel Suarez-Riera, Nicoletta Mangani, Matteo Pavese","doi":"10.1680/jmacr.23.00102","DOIUrl":"https://doi.org/10.1680/jmacr.23.00102","url":null,"abstract":"The use of waste plastic from Waste Electrical and Electronic Equipment (WEEE) as a substitute for natural aggregate in cementitious materials is an increasingly relevant issue. In fact, this would allow to recycle plastics destined for landfills and to decrease the use of new natural resources. However, replacing sand with plastic tends to reduce the mechanical properties of mortars due to the different mechanical properties between the natural aggregate and the waste plastic and the poor interfacial compatibility between the plastic and the cement paste. This work used several strategies to improve the mechanical properties of mortars containing waste plastic. The addition of 1 % of superplasticizer coupled with a lower w/c ratio succeeds in restoring the mechanical properties to values equal to a standard mortar prepared with the natural aggregate, thus obtaining a material that can be used in the construction field.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504813","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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