富含砖粒再生骨料混凝土的耐久性试验研究

Experimental study on durability of recycled concrete with brick coarse aggregates

用富含40%~50%砖粒的再生粗骨料配制再生混凝土,采用渗水高度法和电通量法,分析不同再生骨料取代率和粉煤灰取代率与再生混凝土抗水渗透性以及抗氯离子渗透性的关系,得出抗渗透性最好的再生骨料取代率。然后,在最优再生骨料取代率的情况下,采用快速冻融法研究粉煤灰取代率对再生混凝土的抗冻融性能的影响,并与普通混凝土进行比较。结果表明:富含砖粒的再生混凝土的抗渗透性能比普通混凝土弱,再生骨料取代率的增加会降低其抗渗透性,砖粒类再生骨料取代率为40%的再生混凝土抗渗透性能最好;粉煤灰对再生混凝土具有改性作用,粉煤灰掺量为20%时,再生混凝土的抗渗透性能以及抗冻融性能均最佳;适当取代率下,再生混凝土的抗冻等级能够达到D100。

The recycled concrete is made of recycled coarse aggregates rich in 40% - 50% brick aggregates. And the water penetration height method and electric flux method are used in the test to investigate the effects of the replacement rate of brick coarse aggregate and fly ash on the water permeability and chloride ion penetration and further to find out the best replacement rate. Then, the rapid frozen thaw method is used to investigate the effects of the replacement rate. The results show that the impermeability of recycled concrete is lower than that of ordinary concrete. With the increase of the replacement rate, the impermeability of recycled concrete becomes lower. The fly ash has the modification effects on recycled concrete. The penetration resistance and freeze-thaw resistance performance of recycled concrete are the best when the replacement of cement with fly ash is 20%. Under the appropriate replacement ratio, the frost resistant grade of recycled concrete can reach the D100.