粉煤灰掺量对混凝土冻融性质的影响研究

Research on the Influence of Fly Ash Content on Freeze-thaw Properties of Concrete

通过室内试验对28d和60d龄期下6种粉煤灰掺入量的混凝土试件进行了冻融循环测试,围绕试件的质量损失规律、相对动弹模量参数研究了粉煤灰混凝土的冻融性质。试验测试结果表明:(1)粉煤灰混凝土的抗冻性能随着冻融循环次数增加而降低,降低幅度也逐渐变大;(2)粉煤灰的掺入并不能提高28d龄期混凝土的抗冻性,但对于60d龄期的粉煤灰混凝土,当粉煤灰掺量在30%以下时其相对动弹模量高于未掺粉煤灰的试件;(3)试件中粉煤灰的掺入比高于40%时,其抗冻性能将急剧降低。

The freeze-thaw cycles of concrete blocks with six kinds of fly ash content in 28 d and 60 d ages were tested in laboratory. The freeze-thaw properties of fly ash concrete were studied according to the mass loss law and relative dynamic modulus of elasticity. The test results show that:(1)The frost resistance of fly ash concrete decreases with the increase of freeze-thaw cycles, and the decreasing range gradually increases.(2)The addition of fly ash can not improve the frost resistance of concrete at 28 d age. However, for fly ash concrete at 60 d age, when the content of fly ash is below 30 %, the relative dynamic modulus of elasticity is higher than that of the specimens without fly ash.(3)When the content of fly ash is higher than 40 %, the frost resistance of the specimens will decrease sharply.