承台大体积混凝土施工温控技术研究

Temperature Control and Study of Mass Concrete Construction for Pile Cap

在大体积承台混凝土施工中,由于混凝土方量大,水泥水化所释放的水化热会产生较大的温度变化和收缩作用。混凝土表面和内部的散热条件不同,温度外低内高,形成温度梯度,使混凝土内部产生压应力,表面产生拉应力,表面的拉应力超过混凝土抗拉强度将引起混凝土表面开裂,内部温差过大将导致混凝土出现贯通裂缝。因此,施工中必须对大体积混凝土进行温度控制。以二道松花江特大桥为例,阐述大体积承台混凝土温控措施的实施和取得的效果。

During construction of mass concrete pile cap,due to large concrete volume,the hydration heat released by hydration of cement can produce large temperature change and contraction action.The cooling conditions at the concrete surface and internal are different,tensile stress appears at the surface which surpasses the tensile strength of concrete and lead to crack of concrete,and significant temperature difference inside will lead through crack of concrete.Therefore the temperature must be controlled during construction of mass concrete.Based on Second Songhuajiang River Bridge,the temperature control measures and effects during mass pile cap concrete construction are elaborated in the paper.