Analytical model predicting the concrete tensile stress development in the restrained shrinkage ring test
Analytical model predicting the concrete tensile stress development in the restrained shrinkage ring test
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DOI：
10.1016/j.conbuildmat.2021.124930
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发表时间：
2021-11
影响因子：
7.4
通讯作者：
Yingda Zhang;Sumaiya Afroz;Q. D. Nguyen;Taehwan Kim;J. Eisenträger;A. Castel;Tengfei Xu
中科院分区：
文献类型：
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作者：
Yingda Zhang;Sumaiya Afroz;Q. D. Nguyen;Taehwan Kim;J. Eisenträger;A. Castel;Tengfei Xu
混凝土结构在早期可能会出现意想不到的裂缝。当混凝土中产生的拉应力超过其抗拉强度时，约束变形可能会引起早期裂缝。约束混凝土环试验常用于评价混凝土抵抗收缩引起的早期开裂的能力。本文基于时效调整有效模量理论，通过捕捉约束收缩和拉伸蠕变的影响，提出了约束环试验的分析模型。该分析模型可以根据混凝土弹性模量随时间变化、总自由收缩和拉伸徐变的实验测量，准确预测约束混凝土环的拉应力。还成功进行了数值有限元模拟以验证新的分析模型。重要的是，该模型经过验证，考虑了总共 21 种混凝土，包括 25 MPa 至 100 MPa 的 6 个强度等级。对于每个等级，测试了一种粉煤灰混合物（30%）、两种 GGBFS 混合物（40% 和 60%）以及不含辅助胶凝材料的参考混合物。
Concrete structures may experience unexpected cracking at an early age. Early age cracking can be induced by restrained deformations where tensile stress generated in concrete exceeds its tensile strength. The restrained concrete ring test is often used to evaluate the ability of concrete to resist early age cracking induced by shrinkage. This paper proposed an analytical model of the restrained ring test by capturing the effect of both restrained shrinkage and tensile creep based on the age-adjusted effective modulus theory. The analytical model allows for accurately predicting the tensile stress of the restrained concrete ring based on the experimental measurements of the time-dependent development of elastic modulus, total free shrinkage, and tensile creep of concrete. A numerical finite element simulation was also successfully carried out to validate the new analytical model. Importantly, the model was validated considering a total of 21 concretes consisting of 6 strength grades ranging from 25 MPa to 100 MPa. For each grade, one fly ash blend (30%), two GGBFS blends (40% and 60%) and a reference mix without supplementary cementitious materials were tested.