在分析影响混凝土冻融特性的主要影响因素的基础上,利用冻融循环试验,对比研究了普通混凝土、添加粉煤灰和硅粉的高性能混凝土及高性能再生混凝土的冻融特性。试验结果表明,外掺粉煤灰和硅粉能显著提高普通混凝土和再生混凝土的抗压强度,并显著改善其抗冻性能;添加粉煤灰和硅粉能有效提高再生混凝土的抗压强度,且高于相同配合比的普通混凝土,高性能再生混凝土的抗冻性能接近于普通混凝土,符合实际工程的需要;冻融循环前期的抗冻性能劣化较后期更为严重,建议加强早期的养护。
Freeze-thaw experiments have been conducted to study the frost resistance of common concrete, high performance concrete and high-performance recycled concrete, and the samples were designed according to the deeply investigating to the main influential factors on the behavior freeze-thaw of concrete.Fly ash and silica fume were chosed to use for concrete admixture based on the investitgation.The results show that the strength and frost resistance of common concrete and recycled concrete mixed with fly ash and silica fume are obviously higher than that of common concrete and recycled concrete.The strength of high performance recycled concrete are even higher than that of ordinary concrete with the same mix proportion.The high performance recycled concrete can basically meet the requirements of common concrete in frost resistance and is hoped to use in the practical engineering.Because the more serious degradation of frost performance happened in first dozens of freeze-thaw cycle than in the late, concrete curing in early age is very efficient to improve concrete's antifreeze capacity.