The influence of restraint on the expansion of concrete due to delayed ettringite formation
The influence of restraint on the expansion of concrete due to delayed ettringite formation
复制标题
延迟钙矾石形成对混凝土膨胀的影响
DOI：
10.1016/j.cemconcomp.2021.104062
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发表时间：
2021
影响因子：
10.5
通讯作者：
S. Multon
中科院分区：
文献类型：
--
作者：
Y. Kawabata;N. Ueda;T. Miura;S. Multon
通过实验评估了约束对混凝土中延迟钙矾石形成 (DEF) 引起的膨胀、膨胀压力和开裂模式的影响。特别是，膨胀压力的估计有两种方法：根据钢的应变计算和使用称重传感器直接测量。扩张行为受到约束的强烈影响，尤其是在约束方向。称重传感器测得的膨胀压力为1.9-3.9 MPa，与钢筋应变计算的结果几乎一致。尽管自由 DEF 膨胀比 ASR 更大，但 DEF 的膨胀压力几乎与 ASR 膨胀相同的数量级。根据简化计算，估计所施加的 DEF 膨胀比无应力膨胀减少了约 80%。尽管表面裂纹的总长度与约束程度无关，但表面裂纹的分布会受到约束程度的显着改变。相反，约束情况下的内部裂纹模式相似，而无应力情况下观察到大间隙形成。
The influence of restraint on expansion, expansive pressure, and cracking patterns due to delayed ettringite formation (DEF) in concrete was experimentally evaluated. Especially, the expansive pressure was estimated with two approaches: calculation from the strain of the steel and direct measurement using load cells. The expansive behaviors were strongly affected by the restraint, especially in the restraint direction. The expansive pressure measured by the load cell was 1.9–3.9 MPa, which is nearly consistent with those calculated from the steel bar strain. The expansive pressure of DEF was almost the same order of magnitude as for ASR expansion, despite larger free DEF expansion than ASR. From a simplified calculation, it is estimated that the imposed DEF expansion was reduced from the stress-free expansion by approximately 80%. Although the total length of surface cracking was independent of the degree of the restraint, the distribution of surface cracks was significantly modified by the degree of the restraint. On the contrary, the inner crack pattern was similar for the restraint case while large gap formation was observed for the stress-free case.