冻融环境下水灰比及掺合料对短期混凝土断裂能的影响研究

Influence of Water Cement Ratio and Admixtures on Fracture Energy of Concrete under the Freeze-thaw Cycles Environment

采用RILEM推荐的楔形劈裂试验方法,分别对经历不同冻融循环下水灰比为0.4和0.5的普通混凝土试块以及水灰比为0.5的单掺粉煤灰和复掺粉煤灰与硅灰的混凝土试块,进行28 d标准养护之后,对其进行楔形劈裂试验,并测量其抗压强度及相对动弹性模量。试验结果表明,在28 d标准养护条件下,水灰比越大混凝土的抗冻性表现越差,断裂能,韧性及抗压强度都明显低于水灰比小的混凝土;掺加粉煤灰的混凝土试块抗冻性低于普通混凝土但是抗裂性能以及韧性都明显强于同等水灰比下的普通混凝土试块,双掺粉煤灰和硅灰的混凝土试块的无论是抗冻性能还是抗裂性能、强度以及韧性都明显高于普通混凝土试块和单掺粉煤灰的试块。

Using the wedge splitting test methods recommended by theRILEM, test the concrete specimens through different freeze-thaw cycles. The specimens are the ordinary concrete blocks that water-cement ratio of 0.4, 0. 5, the only adding fly ash cement that water-cement ratio of 0.5 and the adding fly ash and silica fume cement blocks that water-cement ratio of 0.5. Besides, the compressive strength and the relative dynamic elastic modulus were also tested. The test results show that under the standard curing condition for 28 d the greater the frost resistance of concrete water-cement ratio, the worse the performance. The fracture energy, toughness and compressive strength of higher water cement ratio were significantly lower than the lower water-cement ratio of concrete. The frost resistance of cement that adding fly ash is worse than the ordinary cement, but the crack resistances and toughness is better than ordinary cement. Weather the frost resistance, crack resistance, strength or toughness the adding fly ash and silica fume cement is better than the ordinary and adding fly ash cement. Restrained expansion of mortars mixed with different activity.