Bhagyashri Lanjewar, Ravijanya Chippagiri, V. Dakwale, Rahul V Ralegaonkar
Due to rapid industrialization and urbanization there is a significant increase in manufacturing & application of cement which resulted in high CO2 emissions into atmosphere. This leads to investigate alternative binder with reduced CO2 emissions and better performance. The manuscript elaborates the mix design of novel concrete, wherein the principle raw material used was locally available bio-based Blended Ash (BA) procured from co-combustion process with sodium based alkali activators. Physical, chemical, mineral and morphological characteristics of BA were studied. Beside this, investigation of the influence of parameters such as molarity of sodium hydroxide (NaOH), liquid sodium silicate (LSS) to NaOH ratio, fly-ash (FA) to bio-based blended ash (BA) ratio and method of curing on physico-mechanical properties of alkali-activated concrete for sustainable construction material were studied. Higher characteristic strength was attained with increase in these parameters. Maximum characteristic strength of 42.31 MPa at 28th day is obtained with 8 Molar NaOH, LSS/NaOH ratio of 1.5 and FA:BA as 3. The average flexural and split tensile strength obtained is 3.70 MPa and 2.72 MPa respectively. The experimental investigation of the alkali activated concrete using BA and FA proved to be an efficient solution for zero cement concrete with improved performance.
{"title":"Development of bio-based blended ash and fly ash based alkali activated concrete","authors":"Bhagyashri Lanjewar, Ravijanya Chippagiri, V. Dakwale, Rahul V Ralegaonkar","doi":"10.1680/jmacr.22.00251","DOIUrl":"https://doi.org/10.1680/jmacr.22.00251","url":null,"abstract":"Due to rapid industrialization and urbanization there is a significant increase in manufacturing & application of cement which resulted in high CO2 emissions into atmosphere. This leads to investigate alternative binder with reduced CO2 emissions and better performance. The manuscript elaborates the mix design of novel concrete, wherein the principle raw material used was locally available bio-based Blended Ash (BA) procured from co-combustion process with sodium based alkali activators. Physical, chemical, mineral and morphological characteristics of BA were studied. Beside this, investigation of the influence of parameters such as molarity of sodium hydroxide (NaOH), liquid sodium silicate (LSS) to NaOH ratio, fly-ash (FA) to bio-based blended ash (BA) ratio and method of curing on physico-mechanical properties of alkali-activated concrete for sustainable construction material were studied. Higher characteristic strength was attained with increase in these parameters. Maximum characteristic strength of 42.31 MPa at 28th day is obtained with 8 Molar NaOH, LSS/NaOH ratio of 1.5 and FA:BA as 3. The average flexural and split tensile strength obtained is 3.70 MPa and 2.72 MPa respectively. The experimental investigation of the alkali activated concrete using BA and FA proved to be an efficient solution for zero cement concrete with improved performance.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42293631","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}
Concrete carbonation is one of the major factors causing the deterioration of reinforced concrete structures, and accurately predicting carbonation depth is of great significance for the safety assessment of the structure. This study aims to develop a prediction method of carbonation behavior by incorporating multi-source information using the Bayesian method. First, in the proposed approach, the inverse Gaussian process is used to model the evolution process of carbonation depth, which can capture the temporal variability and the monotonicity of the deterioration phenomenon very well. Then, a proper prior for model is determined by absorbing the knowledge of the existing empirical carbonation model. To fuse the accelerated data and field inspection data, the Bayesian inference is performed to update the posterior distributions of model parameters by Gibbs sampling technique. Finally, a practical case is performed to illustrate the validity and accuracy of our proposed approach.
{"title":"A prediction approach of concrete carbonation based on the inverse Gaussian process and Bayesian method","authors":"Long Chen, Tian-Li Huang, Huapeng Chen","doi":"10.1680/jmacr.23.00031","DOIUrl":"https://doi.org/10.1680/jmacr.23.00031","url":null,"abstract":"Concrete carbonation is one of the major factors causing the deterioration of reinforced concrete structures, and accurately predicting carbonation depth is of great significance for the safety assessment of the structure. This study aims to develop a prediction method of carbonation behavior by incorporating multi-source information using the Bayesian method. First, in the proposed approach, the inverse Gaussian process is used to model the evolution process of carbonation depth, which can capture the temporal variability and the monotonicity of the deterioration phenomenon very well. Then, a proper prior for model is determined by absorbing the knowledge of the existing empirical carbonation model. To fuse the accelerated data and field inspection data, the Bayesian inference is performed to update the posterior distributions of model parameters by Gibbs sampling technique. Finally, a practical case is performed to illustrate the validity and accuracy of our proposed approach.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46744649","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 rapid development of the early strength of concrete in cold region is the primary measure to ensure its frost damage resistance. In this context, this paper incorporates 2 wt % of calcium formate into a mortar and electrically cures it by passing an AC at a temperature of –10 °C. During testing, a temperature meter monitors the real-time changes in the internal temperature of the mortar under different energization parameters. The strength of the mortar energized for 1 day is analyzed under different energization parameters. Then, the mortar specimens are moved to a standard box to be cured for 3 and 7 days. XRD, TG-DTG, SEM, and MIP characterize the hydration products, microstructure, and pore structure of the electrically cured mortar specimens. The results show that the initial resistance of the mortar specimen with calcium formate is 25% of that of the mortar without calcium formate. The 3- and 7-days strength of the calcium-formate mortar increases by 59% and 29% respectively, compared to the mortar without calcium formate under the same energization parameters. The combined effect of adding calcium formate and applying electric curing densifies the pore structure of the electrically cured mortar.
{"title":"Early strength development of mortar with calcium formate addition curing by electric field in cold climate","authors":"Zhouzhou Yang, Jianghong Mao, Bixiong Li, Sili Li, Wei Qian, Hao Li, Jun Ren","doi":"10.1680/jmacr.23.00042","DOIUrl":"https://doi.org/10.1680/jmacr.23.00042","url":null,"abstract":"The rapid development of the early strength of concrete in cold region is the primary measure to ensure its frost damage resistance. In this context, this paper incorporates 2 wt % of calcium formate into a mortar and electrically cures it by passing an AC at a temperature of –10 °C. During testing, a temperature meter monitors the real-time changes in the internal temperature of the mortar under different energization parameters. The strength of the mortar energized for 1 day is analyzed under different energization parameters. Then, the mortar specimens are moved to a standard box to be cured for 3 and 7 days. XRD, TG-DTG, SEM, and MIP characterize the hydration products, microstructure, and pore structure of the electrically cured mortar specimens. The results show that the initial resistance of the mortar specimen with calcium formate is 25% of that of the mortar without calcium formate. The 3- and 7-days strength of the calcium-formate mortar increases by 59% and 29% respectively, compared to the mortar without calcium formate under the same energization parameters. The combined effect of adding calcium formate and applying electric curing densifies the pore structure of the electrically cured mortar.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47041335","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}
This study investigates the role of slag substitution (0%, 30%, and 60%), and chloride concentration (1.5% and 3.5% NaCl) on microstructural changes during strength development between 28 and 360 days, rebar corrosion up to 600 days, and chloride binding behaviour in chloride-rich geopolymer concrete (GC). The microstructural changes of GC were evaluated through field-emission-scanning-electron-microscopy (FESEM), energy-dispersive-X-ray-spectroscopy (EDS), X-ray-diffraction (XRD), and Fourier-transform-infrared-spectroscopy (FTIR) analyses. The obtained results indicated that strength enhancement was higher for fly ash-GC (F-GC) mixes. The presence of chloride in GC mixes caused strength reduction at all ages, however, fly ash/slag-GC (F/S-GC) mixes made with higher slag mostly showed lower strength reduction than other mixes. Further, F/S-GC mixes made with higher slag exhibited less negative corrosion potential (Ecor) and lower corrosion current density (Icor) than other mixes, indicating better resistance against rebar corrosion. Chloride binding capacity was mostly higher for GC mixes made with higher slag content. Higher amount of Ca-bearing gels and higher atomic Ca/Si ratio in F/S-GC mixes were responsible for reducing the influence of chloride in strength reduction and rebar corrosion, when compared with F-GC mix. The shifting of Si-O-Si(Al) bond to lower wavenumber indicated more binding gel formation, thereby denser microstructure in F/S-GC mixes.
{"title":"Role of slag in strength, microstructure, and rebar corrosion in chloride-rich geopolymer concrete","authors":"Jnyanendra Kumar Prusty, B. Pradhan","doi":"10.1680/jmacr.22.00247","DOIUrl":"https://doi.org/10.1680/jmacr.22.00247","url":null,"abstract":"This study investigates the role of slag substitution (0%, 30%, and 60%), and chloride concentration (1.5% and 3.5% NaCl) on microstructural changes during strength development between 28 and 360 days, rebar corrosion up to 600 days, and chloride binding behaviour in chloride-rich geopolymer concrete (GC). The microstructural changes of GC were evaluated through field-emission-scanning-electron-microscopy (FESEM), energy-dispersive-X-ray-spectroscopy (EDS), X-ray-diffraction (XRD), and Fourier-transform-infrared-spectroscopy (FTIR) analyses. The obtained results indicated that strength enhancement was higher for fly ash-GC (F-GC) mixes. The presence of chloride in GC mixes caused strength reduction at all ages, however, fly ash/slag-GC (F/S-GC) mixes made with higher slag mostly showed lower strength reduction than other mixes. Further, F/S-GC mixes made with higher slag exhibited less negative corrosion potential (Ecor) and lower corrosion current density (Icor) than other mixes, indicating better resistance against rebar corrosion. Chloride binding capacity was mostly higher for GC mixes made with higher slag content. Higher amount of Ca-bearing gels and higher atomic Ca/Si ratio in F/S-GC mixes were responsible for reducing the influence of chloride in strength reduction and rebar corrosion, when compared with F-GC mix. The shifting of Si-O-Si(Al) bond to lower wavenumber indicated more binding gel formation, thereby denser microstructure in F/S-GC mixes.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46222924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For concrete materials, durability is closely related to mass transport property. The tortuosity of concrete material is an important factor to account for transport property. In this paper, tortuosity of concrete is studied by experiments of MIP and permeation test to consider the exist of aggregate which induce in the interfacial transition zone. Tortuosity gained through corrugated pore structure model (CPSM) and Katz-Thompson model is compared and analyzed to quantify the tortuosity of fly ash concrete. Interfacial transition zone (ITZ) was observed by scanning electron microscope. The results show that the effect of aggregate should be considered when studying the tortuosity of concrete materials. With aggregate value fraction of 43.8%, when considering ITZ around coarse aggregate, concrete tortuosity is 1.29-16.18 times higher than the mortar matrix.
{"title":"Quantification of tortuosity of mortar matrix and concrete with different fly ash content considering interfacial transition zone","authors":"Lianjuan Miao, C. Jiao","doi":"10.1680/jmacr.22.00277","DOIUrl":"https://doi.org/10.1680/jmacr.22.00277","url":null,"abstract":"For concrete materials, durability is closely related to mass transport property. The tortuosity of concrete material is an important factor to account for transport property. In this paper, tortuosity of concrete is studied by experiments of MIP and permeation test to consider the exist of aggregate which induce in the interfacial transition zone. Tortuosity gained through corrugated pore structure model (CPSM) and Katz-Thompson model is compared and analyzed to quantify the tortuosity of fly ash concrete. Interfacial transition zone (ITZ) was observed by scanning electron microscope. The results show that the effect of aggregate should be considered when studying the tortuosity of concrete materials. With aggregate value fraction of 43.8%, when considering ITZ around coarse aggregate, concrete tortuosity is 1.29-16.18 times higher than the mortar matrix.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49393125","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 paper presents result of an investigation conducted to investigate the footprints of fibre's hybridisation on workability, compressive strength, flexural strength and flexural toughness of High Volume Fly Ash Concrete (HVFAC). Different proportions of Polypropylene (PP) and Steel (S)fibres i.e. 100%PP-0%S, 75%PP-25%S%, 50%PP-50%S, 25%PP-75%S and 0%PP-100%S, were incorporated at the total fibre volume fraction of 1.0%. Further, three different methods JCI, ASTM C 1018 and ASTM C 1609 were used for comparative evaluation of various parameters such as toughness, residual strength etc. It was observed that the concrete mixes with higher percentage of PP fibres resulted in lower workability as compared to mixes made with higher percentage of S fibres. Moreover, the concrete mix with 25%PP-75%S fibre combination showed the best results among all concrete mixes and is considered to be the most appropriate for hybridization in HVFAC. Highlights · Effect of hybridization of steel and polypropylene fibres at different percent combination on workability, compressive strength and flexural strength of HVFAC has been investigated. · Flexural toughness of HVFAC incorporated with different percent combination of steel and polypropylene fibres via enumerating various parameters like toughness, residual strength, first and ultimate crack strength, deflection etc. have been determined. · Comparison between different methods i.e. JCI, ASTM C 1018 and ASTM C 1609 has been highlighted. · The mix with 25%PP-75%S (M5) fibre combination showed the best results among all other concrete mixes and is considered to be the most auspicious hybrid fibre combination for enhancing the above given properties.
本文介绍了一项研究结果，旨在研究纤维混杂对大体积粉煤灰混凝土（HVFAC）工作性能、抗压强度、抗弯强度和抗弯韧性的影响。不同比例的聚丙烯（PP）和钢（S）纤维，即100%PP-0%S、75%P-25%S%、50%PP-50%S、25%P-75%S和0%PP-100%S，以1.0%的总纤维体积分数加入。此外，使用三种不同的方法JCI、ASTM C 1018和ASTM C 1609对韧性、残余强度等各种参数进行比较评估。观察到，与用较高百分比的S纤维制成的混合物相比，具有较高百分比的PP纤维的混凝土混合物导致较低的可加工性。此外，在所有混凝土混合物中，含有25%PP-75%S纤维组合的混凝土混合物显示出最好的结果，并且被认为是最适合在HVFAC中杂交的。亮点·研究了钢纤维和聚丙烯纤维在不同组合百分比下的杂交对HVFAC的工作性能、抗压强度和抗弯强度的影响·通过列举韧性、残余强度、初裂强度和极限断裂强度、挠度等参数，测定了不同比例钢纤维和聚丙烯纤维复合HVFAC的弯曲韧性·强调了不同方法（即JCI、ASTM C 1018和ASTM C 1609）之间的比较·在所有其他混凝土混合物中，含有25%PP-75%S（M5）纤维组合的混合物显示出最好的结果，并且被认为是增强上述性能的最有利的混合纤维组合。
{"title":"Hybridisation effect of steel-polypropylene fibres in high volume fly ash concrete","authors":"Onkareshwar Mishra, S. Singh, Shweta Mishra","doi":"10.1680/jmacr.22.00278","DOIUrl":"https://doi.org/10.1680/jmacr.22.00278","url":null,"abstract":"The paper presents result of an investigation conducted to investigate the footprints of fibre's hybridisation on workability, compressive strength, flexural strength and flexural toughness of High Volume Fly Ash Concrete (HVFAC). Different proportions of Polypropylene (PP) and Steel (S)fibres i.e. 100%PP-0%S, 75%PP-25%S%, 50%PP-50%S, 25%PP-75%S and 0%PP-100%S, were incorporated at the total fibre volume fraction of 1.0%. Further, three different methods JCI, ASTM C 1018 and ASTM C 1609 were used for comparative evaluation of various parameters such as toughness, residual strength etc. It was observed that the concrete mixes with higher percentage of PP fibres resulted in lower workability as compared to mixes made with higher percentage of S fibres. Moreover, the concrete mix with 25%PP-75%S fibre combination showed the best results among all concrete mixes and is considered to be the most appropriate for hybridization in HVFAC. Highlights · Effect of hybridization of steel and polypropylene fibres at different percent combination on workability, compressive strength and flexural strength of HVFAC has been investigated. · Flexural toughness of HVFAC incorporated with different percent combination of steel and polypropylene fibres via enumerating various parameters like toughness, residual strength, first and ultimate crack strength, deflection etc. have been determined. · Comparison between different methods i.e. JCI, ASTM C 1018 and ASTM C 1609 has been highlighted. · The mix with 25%PP-75%S (M5) fibre combination showed the best results among all other concrete mixes and is considered to be the most auspicious hybrid fibre combination for enhancing the above given properties.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43897530","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}
Bo-bo Xiong, Cheng Li, Jing Xu, X. Lu, Bin Tian, Bo-Fu Chen, Congcong Lv, Wanhao Liu
Deep penetrating sealer (DPS) is a general term for a class of waterproofing agents that can fill the internal pores of concrete by mixing an alkali metal silicate solution as the base material with catalysts and additives (Jiang et al. 2015). The objective of this study was to investigate the characteristics and mechanism of the effect of different amounts of DPS sprayed on concrete. The water absorption, hydrophilicity, permeability, microhardness, abrasion erosion resistance, and pore structure of concrete were tested at different water cement ratios and sprayed DPS amounts. The test and analysis results showed that compared with the control concrete, concrete absorbed less water and exhibited less permeability after being sprayed with DPS. Moreover, its hydrophilicity, microhardness, and abrasion erosion resistance improved, while its pore volume significantly decreased. The effect was more evident when the amount of sprayed DPS was higher. This study provides a reference for practical engineering applications by demonstrating the variation in concrete surface properties after spraying different amounts of DPS.
{"title":"Influence of deep penetrating sealer on concrete surface performance","authors":"Bo-bo Xiong, Cheng Li, Jing Xu, X. Lu, Bin Tian, Bo-Fu Chen, Congcong Lv, Wanhao Liu","doi":"10.1680/jmacr.23.00014","DOIUrl":"https://doi.org/10.1680/jmacr.23.00014","url":null,"abstract":"Deep penetrating sealer (DPS) is a general term for a class of waterproofing agents that can fill the internal pores of concrete by mixing an alkali metal silicate solution as the base material with catalysts and additives (Jiang et al. 2015). The objective of this study was to investigate the characteristics and mechanism of the effect of different amounts of DPS sprayed on concrete. The water absorption, hydrophilicity, permeability, microhardness, abrasion erosion resistance, and pore structure of concrete were tested at different water cement ratios and sprayed DPS amounts. The test and analysis results showed that compared with the control concrete, concrete absorbed less water and exhibited less permeability after being sprayed with DPS. Moreover, its hydrophilicity, microhardness, and abrasion erosion resistance improved, while its pore volume significantly decreased. The effect was more evident when the amount of sprayed DPS was higher. This study provides a reference for practical engineering applications by demonstrating the variation in concrete surface properties after spraying different amounts of DPS.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49052902","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 current study reports on the long-term structural performance of novel reinforced marine geopolymer concrete beams under accelerated weathering conditions. The study covers the flexural performance of 40 geopolymer concrete beams reinforced with BFRP (Basalt Fibre Reinforced Polymer) bars, including 12 beams under sustained loading when exposed to 3, 6 and 12 months of accelerated marine environment consisting of tidal cycles of seawater at a temperature of 50°C. The experimental results revealed that the novel marine geopolymer concrete reinforced with BFRP bars reported minimal micro and macro-mechanical degradation compared to geopolymer concrete or ordinary concrete beams under the same exposure environment, with and without sustained loading. The BFRP-reinforced SCGC (Self-Compacting Geopolymer Concrete) beams reported 87% residual ultimate load after 12 months of exposure to marine environments, while the sustained loaded BFRP-SCGC (Basalt Fibre Reinforced Polymer- Self-Compacting Geopolymer Concrete) beams reported a residual strength of 79%. In addition, microstructural assessment using SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis revealed that after 12-month exposure, there was a trace of chloride salts indicating the chemical ingress over time; however, the impact on structural properties is not distinct.
{"title":"Long-term performance of Basalt FRP reinforced marine geopolymer concrete in harsh environment","authors":"S. Rahman, Riyadh Al-Ameri","doi":"10.1680/jmacr.23.00035","DOIUrl":"https://doi.org/10.1680/jmacr.23.00035","url":null,"abstract":"The current study reports on the long-term structural performance of novel reinforced marine geopolymer concrete beams under accelerated weathering conditions. The study covers the flexural performance of 40 geopolymer concrete beams reinforced with BFRP (Basalt Fibre Reinforced Polymer) bars, including 12 beams under sustained loading when exposed to 3, 6 and 12 months of accelerated marine environment consisting of tidal cycles of seawater at a temperature of 50°C. The experimental results revealed that the novel marine geopolymer concrete reinforced with BFRP bars reported minimal micro and macro-mechanical degradation compared to geopolymer concrete or ordinary concrete beams under the same exposure environment, with and without sustained loading. The BFRP-reinforced SCGC (Self-Compacting Geopolymer Concrete) beams reported 87% residual ultimate load after 12 months of exposure to marine environments, while the sustained loaded BFRP-SCGC (Basalt Fibre Reinforced Polymer- Self-Compacting Geopolymer Concrete) beams reported a residual strength of 79%. In addition, microstructural assessment using SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis revealed that after 12-month exposure, there was a trace of chloride salts indicating the chemical ingress over time; however, the impact on structural properties is not distinct.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49475445","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. Karimi, M. Ghanooni-Bagha, Ehsan Ramezani, A. A. Shirzadi Javid, Masoud Zabihi Samani
After water, concrete is the most widely used substance on the planet. Cementitious materials carbonation is an inevitable process through which concrete compositions react with carbon dioxide. Carbonation leads to rebar corrosion in reinforced concrete (RC) structures which reduces the structures' longevity. This process increases cement production due to the repair and replacement which brings about more carbon dioxide emission. On the other hand, plain concrete could be one of the most potential materials in terms of CO2 storage. Therefore, understanding concrete carbonation and the influential parameters on its carbonation is significant. Identifying the effective parameters help engineers increase RC structures' carbonation resistance and increase plain concrete capacity as a carbon capture source which could be both cost-effective and environmentally friendly. In this review, an attempt has been made to summarize the present-day knowledge considering the cementitious materials' carbonation and point out the areas that need more research to be conducted. Influential factors have been categorized comprehensively, to do so. Affecting factors have been explained in three parts, containing subsets. Environmental conditions, concrete characteristics, and construction operation effects have been reviewed. Furthermore, concrete carbonation mathematical models proposed by different researchers have been examined to investigate influential parameters in the models and their precision in prediction.
{"title":"Influential factors on concrete carbonation-a review","authors":"A. Karimi, M. Ghanooni-Bagha, Ehsan Ramezani, A. A. Shirzadi Javid, Masoud Zabihi Samani","doi":"10.1680/jmacr.22.00252","DOIUrl":"https://doi.org/10.1680/jmacr.22.00252","url":null,"abstract":"After water, concrete is the most widely used substance on the planet. Cementitious materials carbonation is an inevitable process through which concrete compositions react with carbon dioxide. Carbonation leads to rebar corrosion in reinforced concrete (RC) structures which reduces the structures' longevity. This process increases cement production due to the repair and replacement which brings about more carbon dioxide emission. On the other hand, plain concrete could be one of the most potential materials in terms of CO2 storage. Therefore, understanding concrete carbonation and the influential parameters on its carbonation is significant. Identifying the effective parameters help engineers increase RC structures' carbonation resistance and increase plain concrete capacity as a carbon capture source which could be both cost-effective and environmentally friendly. In this review, an attempt has been made to summarize the present-day knowledge considering the cementitious materials' carbonation and point out the areas that need more research to be conducted. Influential factors have been categorized comprehensively, to do so. Affecting factors have been explained in three parts, containing subsets. Environmental conditions, concrete characteristics, and construction operation effects have been reviewed. Furthermore, concrete carbonation mathematical models proposed by different researchers have been examined to investigate influential parameters in the models and their precision in prediction.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44931451","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}
J. Sim, J. Mun, Jong-Kook Hong, Jong-Cheol Jeon, Sanghee Kim, Keun-Hyeok Yang
This study examined the effect of a developed socket-type shear connector (SSC) on the flexural behavior of a composite basement wall. Twelve composite basement walls (CBW) composed of cast-in-place piles (CIPs) produced with H-shaped steel beams or reinforcing steel bars were prepared by varying the arrangement method and amount of SSC. Two-point loading was applied to simply supported CBW specimens. The test results showed that the CBW specimens with higher amounts of SSC had a higher effective stiffness in the elastic state and moment capacity in the ultimate state, irrespective of the cross-sectional details of the CIP. These trends were particularly prominent for the CBW specimens when SSC used a reinforced steel plate. The post-peak behavior of CBW specimens subjected to a simulated load with a negative external moment, in particular, tended to be more ductile. Consequently, a higher degree of composite action was fully exerted on the composite walls with higher SSC amounts. The nominal partially composite-to-full composite flexural capacity ratios (Mpc/Mfc) of the CBW specimens subjected to the simulated loads with positive and negative external moments can be calculated as 0.83 and 0.91, and 0.79 and 0.90, respectively, at 0.5 and 0.75ηsc using established equations for the sectional details of CBWs with SSC, where ηsc is the normalized shear connector capacity specified in AISC 360-16.
{"title":"Flexural tests on composite basement walls with socket-type shear connectors","authors":"J. Sim, J. Mun, Jong-Kook Hong, Jong-Cheol Jeon, Sanghee Kim, Keun-Hyeok Yang","doi":"10.1680/jmacr.22.00326","DOIUrl":"https://doi.org/10.1680/jmacr.22.00326","url":null,"abstract":"This study examined the effect of a developed socket-type shear connector (SSC) on the flexural behavior of a composite basement wall. Twelve composite basement walls (CBW) composed of cast-in-place piles (CIPs) produced with H-shaped steel beams or reinforcing steel bars were prepared by varying the arrangement method and amount of SSC. Two-point loading was applied to simply supported CBW specimens. The test results showed that the CBW specimens with higher amounts of SSC had a higher effective stiffness in the elastic state and moment capacity in the ultimate state, irrespective of the cross-sectional details of the CIP. These trends were particularly prominent for the CBW specimens when SSC used a reinforced steel plate. The post-peak behavior of CBW specimens subjected to a simulated load with a negative external moment, in particular, tended to be more ductile. Consequently, a higher degree of composite action was fully exerted on the composite walls with higher SSC amounts. The nominal partially composite-to-full composite flexural capacity ratios (Mpc/Mfc) of the CBW specimens subjected to the simulated loads with positive and negative external moments can be calculated as 0.83 and 0.91, and 0.79 and 0.90, respectively, at 0.5 and 0.75ηsc using established equations for the sectional details of CBWs with SSC, where ηsc is the normalized shear connector capacity specified in AISC 360-16.","PeriodicalId":18113,"journal":{"name":"Magazine of Concrete Research","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44979454","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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