José Granja, Renan Rocha Ribeiro, Thomas Russo, Rodrigo Lameiras, Miguel Azenha
The influence of temperature on the hydration of cementitious materials has been traditionally modelled using the maturity concept and Arrhenius law. This approach yields a single material property, called apparent activation energy (Ea), that describes the whole temperature dependence. Determining Ea experimentally has sparked controversy, such as whether the different properties (e.g., compressive strength, tensile strength, E-modulus) exhibit different Ea, whether a single Ea value exists for the entire hydration process, or whether cement paste and concrete possess the same Ea. Furthermore, studies measuring Ea from elastic modulus measurements are truly scarce, likely due to experimental challenges with measuring this property at early-ages. This work investigated the influence of temperature on the elastic modulus evolution of cement paste and concrete. A single mix for each material was tested with the EMM-ARM (Elasticity Modulus Measurement through Ambient Response Method) methodology under three different isothermal conditions. The resulting elastic modulus evolution curves were used to derive Ea evolution curves from two traditional computation methods: the ‘speed’ method and the ‘derivative of speed’ method. Results showed that the elastic modulus evolution of both materials initially presented a constant Ea, independent of temperature and hydration development as preconized by the classical Arrhenius law. However, as hydration progressed to later stages, the activation energy exhibited evident dependencies on both temperature and hydration levels. Cement paste and concrete consistently exhibited different Ea values throughout hydration, with concrete having higher values. The use of the Ea curves to superimpose the different experimental elastic modulus evolution curves by means of the equivalent age concept led to near-perfect superpositions, strengthening the validity of this concept when applied to elastic modulus evolution.
{"title":"Influence of Temperature in the Early-age Elastic Modulus Evolution of Cement Pastes and Concrete","authors":"José Granja, Renan Rocha Ribeiro, Thomas Russo, Rodrigo Lameiras, Miguel Azenha","doi":"10.3151/jact.21.803","DOIUrl":"https://doi.org/10.3151/jact.21.803","url":null,"abstract":"The influence of temperature on the hydration of cementitious materials has been traditionally modelled using the maturity concept and Arrhenius law. This approach yields a single material property, called apparent activation energy (Ea), that describes the whole temperature dependence. Determining Ea experimentally has sparked controversy, such as whether the different properties (e.g., compressive strength, tensile strength, E-modulus) exhibit different Ea, whether a single Ea value exists for the entire hydration process, or whether cement paste and concrete possess the same Ea. Furthermore, studies measuring Ea from elastic modulus measurements are truly scarce, likely due to experimental challenges with measuring this property at early-ages. This work investigated the influence of temperature on the elastic modulus evolution of cement paste and concrete. A single mix for each material was tested with the EMM-ARM (Elasticity Modulus Measurement through Ambient Response Method) methodology under three different isothermal conditions. The resulting elastic modulus evolution curves were used to derive Ea evolution curves from two traditional computation methods: the ‘speed’ method and the ‘derivative of speed’ method. Results showed that the elastic modulus evolution of both materials initially presented a constant Ea, independent of temperature and hydration development as preconized by the classical Arrhenius law. However, as hydration progressed to later stages, the activation energy exhibited evident dependencies on both temperature and hydration levels. Cement paste and concrete consistently exhibited different Ea values throughout hydration, with concrete having higher values. The use of the Ea curves to superimpose the different experimental elastic modulus evolution curves by means of the equivalent age concept led to near-perfect superpositions, strengthening the validity of this concept when applied to elastic modulus evolution.","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136377045","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}
In this study, CO2 quantification was performed on various concrete binder and aggregates by back titration, ther-mogravimetric method, and combustion-infrared absorption method, and their mutual consistency and error factors due to material characteristics were investigated. The back titration measures CO2 directly and is considered the suitable method for both materials, although the effect of sulfide was a concern. On the other hand, the TGA method was revealed to have the possibility of underestimating or overestimating the CO2 determination because the oxidation of sulfides in blast furnace slag, combustion of unburned carbon in fly ash, and dehydration of clay minerals in aggregate overlapping with the temperature range of calcination of calcium carbonate. In the combustion-infrared absorption method, elemental or organic carbon encapsulated in aggregate particles may underestimate or overestimate the CO2 content. In blended cement, sulfur compounds may interfere with the infrared absorption of CO2 and overestimate the amount of CO2. Based on these results, back titration was considered the most suitable method for determining CO2 for concrete materials. It is essential to understand the characteristics of each sample contained and select appropriate methods for CO2 quantification of concrete materials and concrete.
{"title":"Error Factors in Quantifying Inorganic Carbonate CO<sub>2</sub> in Concrete Materials","authors":"Haruka Takahashi, Ippei Maruyama, Takahiro Ohkubo, Ryoma Kitagaki, Yuya Suda, Atsushi Teramoto, Kazuko Haga, Takahiro Nagase","doi":"10.3151/jact.21.789","DOIUrl":"https://doi.org/10.3151/jact.21.789","url":null,"abstract":"In this study, CO2 quantification was performed on various concrete binder and aggregates by back titration, ther-mogravimetric method, and combustion-infrared absorption method, and their mutual consistency and error factors due to material characteristics were investigated. The back titration measures CO2 directly and is considered the suitable method for both materials, although the effect of sulfide was a concern. On the other hand, the TGA method was revealed to have the possibility of underestimating or overestimating the CO2 determination because the oxidation of sulfides in blast furnace slag, combustion of unburned carbon in fly ash, and dehydration of clay minerals in aggregate overlapping with the temperature range of calcination of calcium carbonate. In the combustion-infrared absorption method, elemental or organic carbon encapsulated in aggregate particles may underestimate or overestimate the CO2 content. In blended cement, sulfur compounds may interfere with the infrared absorption of CO2 and overestimate the amount of CO2. Based on these results, back titration was considered the most suitable method for determining CO2 for concrete materials. It is essential to understand the characteristics of each sample contained and select appropriate methods for CO2 quantification of concrete materials and concrete.","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135510699","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 aims to develop a simple yet accurate adaptive homogenization approach for modeling the effective elastic properties of concrete for the whole hydration range from early age to hardened state. Considering available data from a similar microstructure, the method accurately accounts for the impact of cement hydration degree on the effective elastic properties of the heterogeneous concrete mixture. The simulation results have been validated against experimental data and demonstrate exceptional agreement. Also, we have detailly discussed the role of water and the effect of the destructive and non-destructive measurement methods. The model’s simplicity and accuracy make it highly applicable in practical engineering scenarios.
{"title":"An Adaptive Homogenization Scheme for Modeling the Effective Elastic Properties of Early Age Concrete","authors":"Tuan Nguyen-Sy, Minh-Quan Thai, Ngoc-Minh Vu","doi":"10.3151/jact.21.777","DOIUrl":"https://doi.org/10.3151/jact.21.777","url":null,"abstract":"This study aims to develop a simple yet accurate adaptive homogenization approach for modeling the effective elastic properties of concrete for the whole hydration range from early age to hardened state. Considering available data from a similar microstructure, the method accurately accounts for the impact of cement hydration degree on the effective elastic properties of the heterogeneous concrete mixture. The simulation results have been validated against experimental data and demonstrate exceptional agreement. Also, we have detailly discussed the role of water and the effect of the destructive and non-destructive measurement methods. The model’s simplicity and accuracy make it highly applicable in practical engineering scenarios.","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136264029","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}
Yuxuan Zhou, Qing Wang, Mianheng Lai, Johnny Ching Ming Ho
The use of engineered cementitious composite with polyvinyl alcohol fiber has shown excellent potential in building facilities due to its strain-hardening and multiple-cracking features. However, when polyvinyl alcohol fiber melts at around 230°C, spalling behavior of engineered cementitious composite may occur, weakening the mechanical properties and reducing ductility of high strength engineered cementitious composite. Thus, investigating the fire resistance is of great significance. By adding steel fibers to cementitious composites, qualitative and quantitative comparisons were done through observing appearance changes, spalling extent, surface cracking, mass loss, and residual mechanical properties. Results indicate that steel fiber can increase the risk of spalling and surface cracking in high strength engineered cementitious composite, improve residual mechanical abilities also. The ductility varies with steel fiber content at different elevated temperatures. Scanning electron microscopy results show that more hydration products are produced on the surface of steel fiber at 400°C, which improves interface transition zones between fiber and cementitious materials. However, an oxidation film found on the surface of steel fiber at 800°C triggers negative effect on bridging.
{"title":"Steel Fiber to Improve Thermal Resistance of High Strength PVA-ECC after Exposure to Elevated Temperature","authors":"Yuxuan Zhou, Qing Wang, Mianheng Lai, Johnny Ching Ming Ho","doi":"10.3151/jact.21.748","DOIUrl":"https://doi.org/10.3151/jact.21.748","url":null,"abstract":"The use of engineered cementitious composite with polyvinyl alcohol fiber has shown excellent potential in building facilities due to its strain-hardening and multiple-cracking features. However, when polyvinyl alcohol fiber melts at around 230°C, spalling behavior of engineered cementitious composite may occur, weakening the mechanical properties and reducing ductility of high strength engineered cementitious composite. Thus, investigating the fire resistance is of great significance. By adding steel fibers to cementitious composites, qualitative and quantitative comparisons were done through observing appearance changes, spalling extent, surface cracking, mass loss, and residual mechanical properties. Results indicate that steel fiber can increase the risk of spalling and surface cracking in high strength engineered cementitious composite, improve residual mechanical abilities also. The ductility varies with steel fiber content at different elevated temperatures. Scanning electron microscopy results show that more hydration products are produced on the surface of steel fiber at 400°C, which improves interface transition zones between fiber and cementitious materials. However, an oxidation film found on the surface of steel fiber at 800°C triggers negative effect on bridging.","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136265917","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}
Vo Minh Chi, Nguyen Min Hai, Nguyen Lan, Nguyen Van Huong
Cement-based materials with self-sensing capabilities have the potential to be used as compression load cells in various applications. This study aims (i) to clarify the change in resistivity in self-sensing mortar (SSM) under nondestructive compressive stress and the underlying mechanism of this change, (ii) to examine the effects of different conditions such as electric circuit and specimen dimension on this relationship. The study involved SSM specimens containing 7% carbon black powder with various parameters, including excitation voltage, intermediate resistor for the electric circuit, and electrode distance, dimensions of the cube SSM specimen. Additionally, scanning electron microscopy (SEM) observations were performed to investigate the dispersion of carbon black in the cementitious matrix. SEM observations reveal the agglomeration and dispersion of carbon black within the cementitious matrix, creating a conductive network in SSM. The measurement results showed the resistivity change was nonlinear but displayed nearly linear behavior within a specific range of compressive stress. The slope of this change increased with larger specimen cross-section, shorter electrode distance, and a smaller value for the intermediate resistor in the electric circuit. A regression analysis was conducted to predict the change in resistivity of SSM under nondestructive compressive stress, while taking these effects into account.
{"title":"Stress Self-sensitivity of Carbon Black-filled Mortar under Nondestructive Compression and the Effects of Electric Circuit and Specimen Dimensions","authors":"Vo Minh Chi, Nguyen Min Hai, Nguyen Lan, Nguyen Van Huong","doi":"10.3151/jact.21.762","DOIUrl":"https://doi.org/10.3151/jact.21.762","url":null,"abstract":"Cement-based materials with self-sensing capabilities have the potential to be used as compression load cells in various applications. This study aims (i) to clarify the change in resistivity in self-sensing mortar (SSM) under nondestructive compressive stress and the underlying mechanism of this change, (ii) to examine the effects of different conditions such as electric circuit and specimen dimension on this relationship. The study involved SSM specimens containing 7% carbon black powder with various parameters, including excitation voltage, intermediate resistor for the electric circuit, and electrode distance, dimensions of the cube SSM specimen. Additionally, scanning electron microscopy (SEM) observations were performed to investigate the dispersion of carbon black in the cementitious matrix. SEM observations reveal the agglomeration and dispersion of carbon black within the cementitious matrix, creating a conductive network in SSM. The measurement results showed the resistivity change was nonlinear but displayed nearly linear behavior within a specific range of compressive stress. The slope of this change increased with larger specimen cross-section, shorter electrode distance, and a smaller value for the intermediate resistor in the electric circuit. A regression analysis was conducted to predict the change in resistivity of SSM under nondestructive compressive stress, while taking these effects into account.","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135354797","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}
Syed Badar Farooq, M. Sikandar, Muhammad Hanif Khan, Qiuhong Zhao, Han Zhu, Nabi Ullah, Muhammad Noman, Inam Ul Haq Khan
{"title":"Effect of Sodium Paraben-based Anti-fungal Agents in Controlling the Aspergillus Niger Growth in Cement Mortars","authors":"Syed Badar Farooq, M. Sikandar, Muhammad Hanif Khan, Qiuhong Zhao, Han Zhu, Nabi Ullah, Muhammad Noman, Inam Ul Haq Khan","doi":"10.3151/jact.21.680","DOIUrl":"https://doi.org/10.3151/jact.21.680","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48905844","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}
Allahverdi Bahrami, K. Behfarnia, Reza Soltanabadi
{"title":"The Efficiency of the Ordinary Polypropylene Fiber in Producing One-part Alkali-Activated Slag Composites with Strain-Hardening Behavior","authors":"Allahverdi Bahrami, K. Behfarnia, Reza Soltanabadi","doi":"10.3151/jact.21.695","DOIUrl":"https://doi.org/10.3151/jact.21.695","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45599368","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}
Özlem Kasap Keskin, Süleyman B Keskin, Kamil Tekin
{"title":"Predicting the Ultimate Properties of Engineered Cementitious Composites by Maturity Method","authors":"Özlem Kasap Keskin, Süleyman B Keskin, Kamil Tekin","doi":"10.3151/jact.21.735","DOIUrl":"https://doi.org/10.3151/jact.21.735","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44368539","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}
{"title":"Experimental Study of Graphene Oxide on Hydration Process of Tricalcium Silicate","authors":"Zhanguo Li, Huan Du, Zigeng Wang, Yue Li","doi":"10.3151/jact.21.719","DOIUrl":"https://doi.org/10.3151/jact.21.719","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46111667","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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