冻融-碳化作用下掺粉煤灰混凝土强度劣化试验

Strength Degradation Test of Fly Ash Concrete with Freeze-Thaw Carbonization

为研究掺粉煤灰混凝土受冻融和碳化双重作用下的抗压强度劣化规律,制作了常用水胶比情况下的混凝土试件,进行了单轴抗压强度试验研究。结果表明:混凝土中掺粉煤灰比例相同情况下,在设计试验期内,先冻融后碳化的混凝土强度劣化约为32%,先碳化后冻融的混凝土强度劣化约为25%,而只受冻融作用的混凝土强度劣化约为21%,则双重因素作用下强度劣化明显大于单一因素;水胶比越小,粉煤灰混凝土单轴抗压强度越大,且在各因素作用下强度劣化速度较慢。这为北方地区使用掺粉煤灰混凝土在冻融和碳化作用下的强度劣化规律提供了试验依据。

In order to study the deterioration rule of compressive strength of fly ash concrete under the double action of freeze-thaw and carbonation, concrete blocks with different water-binder ratio were made to test their uniaxial compressive strength in laboratory. The results show that under the condition of the same proportion of fly ash in concrete, in the design of the trial period, the strength of the concrete ,which was first freeze-thaw and then carbonization, deteriorate to 32% and the strength of the concrete ,which was first carbonization and then freeze-thaw, deteriorate to 25%, while the strength deteriorate to 21% only under the effect of freeze-thaw. So, the deterioration of the dual factors obviously higher than the single factor;the lower the water-binder ratio, the higher of the uniaxial compressive strength of the concrete, and the slower of the speed of deterioration of uniaxial compressive strength. This provides the experimental basis for the deterioration law of the strength of fly ash concrete mixed with the double action of freezing and carbonization in the north.