高温下高性能混凝土早期抗裂性能试验研究

Study on the Early Crack Resistance of High Performance Concrete Under the Condition of High Temperature Curing

为了研究高地热条件下隧洞衬砌混凝土的早期抗裂性,使用刀口法研究温度、水胶比和粉煤灰掺量对高性能混凝土早期抗裂性的影响。试验结果表明:温度是影响混凝土早期抗裂性的主要因素,粉煤灰掺量次之,水胶比的影响可以忽略;混凝土早期抗裂性随温度的升高而降低,随粉煤灰掺量的增加先降低后升高,试验确定的最优粉煤灰掺量为20%;在高温条件下,粉煤灰混凝土的早期抗裂性优于普通硅酸盐混凝土的,能在提高混凝土早期抗裂性的同时降低工程造价。

In order to study the early crack resistance of tunnel lining concrete under the condition of high geother^mal, we tested the influ-ence of temperature, water-binder ratio and dosage of fly ash on the early crack resistance of high perfor^mance concrete by knife-edge method. The experimental data show that the temperature is the main factor influencing the early crack resistance of concrete, then is the dosage of fly ash and the influence of water-binder ratio can be ignored. The early crack resistance of concrete decreases with the increase of temperature, and decreases first then increases with the increase of the dosage of fly ash and the best dosage is 20%. The early crack resistance of fly ash concrete is better than that of the ordinary cement concrete under the condition of high temperature curing and i t can lowering the engineering cost as well.