再生烧结黏土砖粉活性及其在再生混凝土中的应用研究

Study on Activity of Recycled Sintered Clay Brick Powder and Its Application Effect in Recycled Concrete

针对黏土砖类建筑垃圾存量大、处理难和利用率低的问题,研究了再生砖粉活性及其替代粉煤灰应用于再生混凝土的性能。结果表明:再生砖粉活性指数为73%,满足水泥活性混合材料中粉煤灰的活性指数要求。再生砖粉活性源于其内部SiO_(2)、Al_(2)O_(3)等与水泥水化产物Ca(OH)_(2)反应生成的硅酸盐和铝酸盐水合物使混凝土更加密实。28 d时,50%取代率再生砖粉混凝土抗压强度明显优于粉煤灰混凝土。相对粉煤灰混凝土,再生砖粉混凝土中Ca(OH)_(2)减少速率较慢,密实较差。

Aiming at the problems of large stock of clay brick-type construction waste,difficult treatment and low utilization rate,the activity of recycled brick powder and its performance of replacing fly ash applied to recycled concrete were studied.The results showed that the activity index of recycled brick powder was 73%,which met the requirement of activity index of fly ash in cement active mixed materials.The activity of recycled brick powder came from the silicate and aluminate hydrate generated by the reaction of internal SiO_(2),Al_(2)O_(3),etc with Ca(OH)_(2),a hydration product of cement,which made the concrete denser.The compressive strength of recycled brick powder concreted with 50%substitution rate was significantly better than that of fly ash concrete at 28 d.The compressive strength of recycled brick powder concreted with 50%substitution rate was significantly better than that of fly ash concrete.Compared with fly ash concrete,Ca(OH)_(2)reduction rate in recycled brick dust concrete was slower and the densification was poorer.