大流动性再生粗集料混凝土配合比设计方法

Design of Mix Proportion for High Flowing Recycled Coarse Aggregate Concrete

采用相同砂浆体积(EMV)方法配制再生粗集料混凝土,可节省水泥及细集料的用量,其强度及弹性模量与对比天然集料混凝土(NAC)相近,但由于新拌砂浆含量小而使其流动性能变差.给出了EMV方法的改进方法及具体设计步骤,并应用该改进方法配制2种不同来源再生粗集料的大流动性再生粗集料混凝土(FRAC),测定其坍落度、干湿表观密度、立方体抗压强度、轴心抗压强度、劈裂抗拉强度以及弹性模量.结果表明:采用改进EMV方法可配制出满足和易性要求的FRAC,而且与传统方法配制的FRAC相比,其各项性能指标更接近对比NAC.

Recycled aggregate concrete was prepared by using equal mortar volume（EMV） method. The advantage of the method lies in fact that the cement and fine aggregate can de saved, keeping the strength and elastic modulus approximately equal to those of the concrete of natural aggregate. However, the slump reduced due to the lower new mortar volume. The improved EMV method and the detailed steps of design were proposed. Using the improved method, two kinds of high flowing recycled aggregate concrete （FRAC） were prepared with recycled coarse aggregate obtained from two different origins respectively. For each case, the indicators such as slump, fresh and hardened densities, compressive strength, axial compressive strength, splitting tensile strength and elastic modulus were measured. The results show that the FRAC meets the requirement of workability and other properties are similar to control natural aggre- gate eoncrete（NAC）, better than the FRAC mixed with conventional aggregate replacement method.