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研究2种坍落度、掺与未掺防冻剂混凝土在不同预养时间下抗压强度、混凝土50次冻融强度损失率(Δfc)及混凝土的渗透系数(P)。依据混凝土受冻临界强度的定义对上述试验数据进行分析。结果表明:未掺防冻剂的负温混凝土经历一定的预养时间,即使达到受冻临界强度,但其抗冻性、抗渗性指标均在较大范围内波动。低塑性时,高防冻组分的防冻剂降低了(-7+28)d混凝土的抗压强度,使其不能满足95%基准混凝土抗压强度指标要求。高减水组分防冻剂混凝土满足受冻临界强度的同时,其50次冻融强度损失率及渗透系数均很低。随着负温混凝土坍落度的增大(依靠减水剂改变),其抗冻性、抗渗性降低,随着预养护时间的延长,上述耐久性指标得到改善。
The compressive strength of concrete with two kinds of slump, concrete without doping and un-dredged concrete at different pre-seasoning time, the loss rate of 50 freeze-thaw strength (Δfc) and the permeability coefficient of concrete (P) were studied. Based on the definition of the critical strength of concrete subjected to freezing, the above experimental data were analyzed. The results show that the negative temperature concrete without antifreeze experienced a certain pre-maintenance time, even if it reaches the critical strength of freezing, but its frost resistance and impermeability indexes fluctuate in a wide range. Low plasticity, high antifreeze component of antifreeze reduces (-7 +28) d of concrete compressive strength, it can not meet the 95% benchmark compressive strength requirements. While the anti-freeze concrete with high water-reducing component meets the critical strength of freezing, its 50-times loss of freeze-thaw strength and its permeability coefficient are very low. As the slump of negative temperature concrete increases (depending on the water reducer), its frost resistance and impermeability decrease. With the increase of pre-curing time, the above durability index is improved.