盾构土与沙漠砂制备再生砖的性能研究

Study on performance of recycled bricks prepared from shield soil and desert sand

研究了不同含水率下不同取代率的沙漠砂对再生砖制坯、烧结、微观形貌、力学性能及含水率等因素的影响规律。研究结果表明:沙漠砂可有效补充再生砖中SiO2等必要的化学成分,提供稳定充分的烧结环境,满足烧结要求;陈化时间需稳定在20h左右,测得陈化料含水率20%、25%、30%时的干燥敏感性系数分别为0.69、0.72、1.04;含水率为25%~28%时,再生砖成型效果最佳;沙漠砂取代率为27%~30%时可有效承担砖体骨架作用,再生砖抗压强度及吸水率分别稳定在15.5MPa~17.3MPa、9.5%~10.04%之间;盾构土和沙漠砂混合制备再生砖,性能优异,综合效益显著,可拓宽建筑垃圾资源化利用途径,满足市场需求,具有一定的实际应用价值。

In this paper,the influence of desert sand with different substitution rates under different moisture content on the billet making,sintering,microscopic morphology,mechanical properties and moisture content of recycled bricks is studied.The results show that desert sand can effectively supplement the necessary chemi⁃cal components such as SiO2 in recycled bricks,provide a stable and sufficient sintering environment,and meet the firing requirements.The aging time needs to be stable at about 20h,and the drying sensitivity coeffi⁃cients of the aged material are 0.69,0.72 and 1.04 when the moisture content is 20%,25%and 30%,respec⁃tively,and the molding effect of recycled bricks is the best when the moisture content is 25%~28%.When the substitution rate of desert sand is 27%~30%,it can effectively assume the role of brick skeleton,and the com⁃pressive strength and water absorption rate of recycled bricks are stable between 15.5 MPa~17.3MPa and 9.5%~10.04%,respectively.The preparation of recycled bricks by mixing shield soil and desert sand has ex⁃cellent performance and significant comprehensive benefits,which can broaden the way of resource utilization of construction waste,meet market demand,and have certain practical application value.