碱-硅酸反应对混凝土力学性能的影响

The effect of ASR on concrete mechanical properties

采用实际工程活性骨料,并参照工程配合比,成型混凝土抗压、劈拉、抗弯和轴向拉伸试验试件。经过28d标准养护后,移入温度60±1℃,相对湿度为90%~95%的养护箱中,使碱-骨料反应加速进行。在混凝土达到不同的膨胀量时取出,进行力学性能测试。结果表明,混凝土的劈裂抗拉强度、抗弯强度和轴向抗拉强度随碱-骨料反应膨胀量的增大而降低。用相对动弹性模量表征混凝土的损伤,根据混凝土力学性能和损伤量的对应关系,初步得出了ASR混凝土的力学性能衰减模型。

A kind of reactive aggregate from practical project was used to prepare concrete samples in this paper. Based on practical mix proportion of hydraulic project, concrete was prepared to investigate the ef- fect of ASR on the concrete mechanical properties, including compression strength, splitting tensile strength, bending strength, and ultimate tensile strength. After cured in standard curing room for 28 days, all the concrete samples were moved to the curing room with a curing temperature of 60±1℃ and a relative humidity of 90%-95%. At several certain AAR expansion values, mechanical properties were tested. The results showed that the concrete mechanical properties decreased with the increase of damage amount resulting from AAR. The damage of concrete was characterized by relative dynamic modulus of elasticity; according to the relationship between concrete mechanical properties and damage amount, the prediction model about the damage degree of mechanical properties was established.