桥梁大体积混凝土温度控制与防裂

针对桥梁大体积高强度混凝土施工特点，从配合比设计、材料选择、降温度保湿方法等方面分析了大体积混凝土的温度特性，指出水泥在硬化过程中释放出大量的水化热，产生的温度应力超过混凝土的极限抗拉强度是导致裂缝的主要原因。结合实测大体积混凝土结构温度场，分析了造成大体积混凝土开裂的主要因素。结果表明：做好冷却和保温，对混凝土的最高温度和最高温升速率进行限制，可提高混凝土的极限拉应变；缓慢降温可充分发挥混凝土的应力松弛效应，提高抗拉性能。

Temperature Control and Anti-crack of Massive Concrete in Large Bridges

According to the performance of massive high strength concrete in large bridges, the proportioning design, material selection and maintenance methods for constructing massive concrete are presented. The temperature characteristic and temperature control methods of massive concrete are analyzed, the main factors of massive concrete cracking are studied with the tested temperature field computing. It is proved that to control the high temperature and the increasing rate of temperature can improve concrete ultimate tensile strains, and to low the decreasing rate of temperature can lead to stress relaxation and better tensile property. 1 tab, 4 figs, 6 refs.