{"title":"Meso-scale Modeling of Anomalous Moisture Transport in Concrete Considering Microstructural Change of Cement-based Material","authors":"Puttipong Srimook, Keigo Ogawa, Ippei Maruyama","doi":"10.3151/jact.22.344","DOIUrl":"https://doi.org/10.3151/jact.22.344","url":null,"abstract":"</p><p>Moisture transport is the key phenomenon indicating the deterioration of the durability and structural performance of concrete structures. Although various studies have attempted to evaluate moisture transport in concrete, an anomalous behavior, which does not follow the root-t law compared to other porous material, was not explicitly taken into account. To quantitatively evaluate anomalous moisture transport, this study developed a couple of numerical methods between the truss-network model (TNM) and the rigid-body-spring model (RBSM) for this purpose. The colloidal behavior of calcium-silicate-hydrate (C-S-H), which is the major phase of cement-based material, was introduced to consider the anomalous behavior and mechanical response regarding the microstructural change of cement paste as well as cracks that significantly accelerate the moisture transport in concrete. The numerical results indicated that both microstructural change of cement paste and rapid absorption through cracks cause anomalous behavior. In addition, the numerical results suggest that volumetric change of cement paste should rely on water content related to the colloidal behavior of C-S-H in order to reproduce the realistic expansion and the closure of cracks during a rewetting process that affects structural performance and durability of concrete.</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511574","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":"Test Method of Segregation Resistance of High Fluidity Concrete Based on Numerical Simulation of Dynamic Segregation of Coarse Aggregate","authors":"Zhisong Xu, Zhuguo Li, Jiaping Liu, Wei Chen, Jianzhong Liu, Fangyu Han","doi":"10.3151/jact.22.372","DOIUrl":"https://doi.org/10.3151/jact.22.372","url":null,"abstract":"</p><p>The workability of high fluidity concrete (HFC) also depends on its segregation resistance besides fluidity, and gap-passing ability, etc. Currently, there is a lack of easy, quantitative method for evaluating segregation resistance. Efficient assessment is crucial for construction applications of HFC. This paper aims to propose a simple test method for the segregation resistance of HFC on basis of the J-ring test that has been generally used for evaluating the fluidity and passing ability of HFC. Experiment and numerical simulation of J-ring test were conducted for HFCs with different fluidity and segregation resistance. The fresh concretes were treated as two-phase granular fluids of matrix mortar and coarse aggregate in simulation by a newly developed particle meshless method, called DPMP-MPS. The flow and segregation behaviors of the HFCs during J-ring test under different lifting speeds of slump cone were investigated. The numerical results demonstrate a close correlation between the final flow value to slump value ratio (<i>SF<sub>-J</sub></i>/<i>SL<sub>-J</sub></i> ratio) and the segregation resistances of HFCs. Consequently, the J-ring test can assess the segregation resistance based on the <i>SF<sub>-J</sub></i>/<i>SL<sub>-J</sub></i> ratio. Notably, it emphasizes that, for precise evaluation of HFC workability using the J-ring test, the lifting speed of the slump cone should fall within the range of 10 to 15 cm/s.</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511575","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":"A Proposal of Maturity Function on the Strength Development of Concrete Below the Freezing Point","authors":"M. Taniguchi, Yukio Hama","doi":"10.3151/jact.22.311","DOIUrl":"https://doi.org/10.3151/jact.22.311","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141374183","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":"Development of Silicate-Based Surface Impregnation Solution with High Permeability for Restoration of Degraded Concrete","authors":"Tatsuya Kitada, Zhuguo Li","doi":"10.3151/jact.22.294","DOIUrl":"https://doi.org/10.3151/jact.22.294","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141375995","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":"Developing High-Strength Geopolymer using Least Activator and Pressure-Applied Casting: Techno-Enviro-Economic Performance","authors":"Khuram Rashid, Fahad Masud","doi":"10.3151/jact.22.327","DOIUrl":"https://doi.org/10.3151/jact.22.327","url":null,"abstract":"</p><p>This work is designed by coupling fly ash (FA) with dune sand (DS) for high-strength geopolymer activated in an alkaline environment under pressure-applied casting. Initially, the proportion of FA and DS is optimized with the least activator dosage to obtain higher than the compressive strength of 50 MPa. A uniaxial pressure is applied on a semi-dry mixture containing the least activators and immediately demolded, involving rapid production for the industrialization purpose of the paving blocks. The experimental study revealed that the FA-DS proportion of 1:1, with a liquid-to-solid ratio of 0.16, achieved a compressive strength of 54.4 MPa. Consequently, the coupling of DS provides an occupying effect and reduces the required activator quantity. The strength gain mechanism is discussed at the molecular level by analyzing Fourier-transform infrared. Finally, the technical performance of the strength and the density is evaluated on the real size 203 × 101 × 80 mm prism and compared with the commercially available conventional concrete blocks. Besides, the enviro-economic performance in terms of CO<sub>2</sub> emissions and the cost are analysed as well. It is concluded that the developed block is a more environmentally sustainable and economically viable alternative to conventional concrete blocks.</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141259329","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":"Influence of Nano-CaCO3 on the Strength and Fatigue Behavior of Concrete with 30% or 50% Recycled Coarse Aggregates","authors":"Yousheng Deng, Liqing Meng, Zhang Keqin, Fu Yunbo","doi":"10.3151/jact.22.279","DOIUrl":"https://doi.org/10.3151/jact.22.279","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101868","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}
Zhihang Wang, Erlei Bai, Chaojia Liu, Yuhang Du, Biao Ren
{"title":"Polymer/Carbon Fiber Co-modification: Dynamic Compressive Mechanical Properties of Carbon Fiber Modified Polymer Reinforced Concrete","authors":"Zhihang Wang, Erlei Bai, Chaojia Liu, Yuhang Du, Biao Ren","doi":"10.3151/jact.22.267","DOIUrl":"https://doi.org/10.3151/jact.22.267","url":null,"abstract":"</p><p>To explore the dynamic compressive mechanical properties of carbon fiber modified polymer reinforced concrete (CFMPRC), the 100 mm diameter SHPB (Split Hopkinson Pressure Bar) test system was used to carry out impact compression tests of CFMPRC with different carbon fiber volume content (0.1%, 0.2%, 0.3% and 0.4%). The dynamic stress-strain curves and fracture morphology of CFMPRC under different strain rates (37.7 s<sup>-1</sup> to 132.2 s<sup>-1</sup>) were obtained, and the effects of strain rate and carbon fiber content on dynamic compressive strength, deformation and toughness of CFMPRC were analyzed. The results show that the dynamic compressive strength, deformation and toughness of CFMPRC have obvious strain rate strengthening effect and carbon fiber strengthening effect. The dynamic compressive strength, dynamic increase factor (<i>DIF</i>), dynamic peak strain and impact toughness of CFMPRC increase with strain rate gradually. The dynamic compressive mechanical properties of polymer reinforced concrete are improved by adding carbon fiber, and the optimal carbon fiber content is 0.2%. When carbon fiber content is 0.2%, the strain rate sensitivity of CFMPRC is the strongest, and the increase of strength is the maximum. Carbon fiber can bridge the internal cracks of concrete, and shows the co-modification effect with polymer. Polymer can enhance the carbon fiber/concrete matrix interface, which makes carbon fiber exert its effect more effectively.</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140925450","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":"Freeze-thaw Resistance of Concrete using Ground Granulated Blast-furnace Slag and Blast-furnace Slag Sand in Salt Water","authors":"Toshiki Ayano, Takashi Fujii, Kanako Okazaki","doi":"10.3151/jact.22.253","DOIUrl":"https://doi.org/10.3151/jact.22.253","url":null,"abstract":"</p><p>The freeze-thaw resistance of concrete is significantly lower in salt water than in fresh water. Concrete deteriorates through repeated freezing and thawing, but in salt water, freezing alone leads to destruction. This paper investigated the effect of calcium hydroxide in concrete on the failure of concrete under such low temperatures. Calcium hydroxide precipitates at the transition zone between aggregate and cement paste due to the hydration of cement. The lower the temperature and the higher the concentration of salt water, the more calcium hydroxide dissolves. From concrete, more calcium hydroxide is eluted in salt water than in fresh water. This accelerates the deterioration of mortar and concrete due to freeze-thaw action. Mortar and concrete using ground granulated blast-furnace slag produces less calcium hydroxide. In mortar and concrete using blast-furnace slag sand, calcium hydroxide precipitated around the aggregate reacts with cement paste and blast-furnace slag sand to modify the transition zone. From these results, it was clarified that concrete using blast-furnace slag exhibits high freeze-thaw resistance even in salt water.</p><p>This paper is the English translation of the authors’ previous work [Ayano, T., Fujii, T. and Okazaki, K., (2023). “Freeze-thaw resistance of concrete using ground granulated blast-furnace and blast-furnace slag sand in salt water.” <i>Japanese Journal of JSCE</i>, 79(12), 23-00042. (in Japanese)].</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942399","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}
Harry Hermawan, Virginie Wiktor, Pedro Serna, Elke Gruyaert
{"title":"Modification of Concrete Mix Design with Crystalline Admixture for Self-healing Improvement","authors":"Harry Hermawan, Virginie Wiktor, Pedro Serna, Elke Gruyaert","doi":"10.3151/jact.22.237","DOIUrl":"https://doi.org/10.3151/jact.22.237","url":null,"abstract":"","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140659399","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":"Time Dependency and Similarity of Water Permeability of Fly Ash Concrete Between Laboratory Environment and Site Environment","authors":"Junzhi Zhang, Libin Zhou, Yucheng He, Yurong Zhang","doi":"10.3151/jact.22.219","DOIUrl":"https://doi.org/10.3151/jact.22.219","url":null,"abstract":"</p><p>Effects of fly ash (FA) content and environmental factors on the water permeability were studied, and the similarity relationship of time-dependent water permeability coefficient in site and laboratory environment was discussed. Meanwhile, the main microstructure parameters and their time-dependent characteristics were analyzed by the NMR method. Finally, the correlation between water permeability and porosity in two environments was analyzed. Results show that water permeability coefficient of FA concrete both decreased with exposure time in two environments. FA can effectively improve the water impermeability, and the improvement effect increased with FA content in the later exposure period. Laboratory environment accelerated the decrease of water permeability and porosity. However, in the later stage, the decrease degree was not as good as that in the site environment. Pores with size of 10 to 100 nm occupy the main part of pores in FA concrete and the proportion of harmful pores of diameter 100 nm or larger decreased with exposure time. The water permeability coefficient and porosity of concrete exposed for 520 days in laboratory are close to that exposed for 800 to 1000 days in site, showing a good time dependent correlation in both environments, and the correlation with exposure time is stronger than that considering FA content.</p>\u0000<p></p>","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140624070","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}