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冬季混凝土施工如不采取一定措施,就会因冻害造成工程质量事故。混凝土冻害主要是由于受冻融循环作用造成的。在施工后的混凝土硬化初期,强度很低,内部存有一些孔隙并含有尚末与水泥化合的自由水,这时如遇到冰冻,靠近混凝土表面孔隙中自由水冻结成冰,体积膨胀并对孔壁产生压力,当它超过孔壁的抗拉强度,孔壁就会产生微裂缝,若受到多次冻融循环,微裂缝便向纵深发展,并扩
If concrete construction in winter does not take certain measures, it will cause project quality accidents due to freezing damage. The freezing damage of concrete is mainly caused by the freeze-thaw cycles. In the early stage of concrete hardening after construction, the strength is very low. There are some pores in the interior and free water that is still cemented with cement. When it encounters freezing, free water in the pores near the concrete surface freezes and expands in volume. The pore wall generates pressure. When it exceeds the tensile strength of the pore wall, the pore wall will have micro-cracks. If it is subjected to multiple freeze-thaw cycles, the micro-cracks will develop in depth and expand.