回弹法检测再生混凝土抗压强度研究

针对再生粗骨料取代率分别为0％，30％，50％，70％和100％的150块再生混凝土试块，采用普通混凝土回弹仪进行了抗压强度检测试验研究。研究结果表明，回弹法可以用于再生混凝土抗压强度检测。通过采用多种回归模型进行比较分析，得到了再生混凝土统一测强曲线公式。定量分析表明，其测试精度满足混凝土质量控制要求。为反映再生粗骨料取代率的影响，文中还给出了按再生粗骨料取代率分类的测强曲线及回归方程。最后，对比了再生混凝土与普通混凝土全国统一曲线。结果表明，再生混凝土的表面硬度小于普通混凝土，但其随抗压强度增加的速度快于普通混凝土。

Inspection of compressive strength of recycled concrete by rebound method

In this paper,the compressive strength of recycled aggregate concrete with different recycled coarse aggregate(RCA) replacement ratios is inspected by rebound method.The test results indicate that it is feasible to inspect the compressive strength of recycled concrete by rebound method.A unified regression formula for inspection of the compressive strength of recycled concrete with different RCA replacement ratios is obtained.The regression formula can meet the requirement of the quality of concrete through regression analysis.In order to reflect the influence of RCA replacement ratio,several regression formulas for each RCA replacement ratio are presented.A comparison about the unified f_(cu)-R_m curves between recycled aggregate concrete (RAC) and natural aggregate concrete(NAC) is made.The results show that the surface hardness of RAC is lower than that of NAC.However,as the compressive strength increases,the improvement of surface hardness of RAC is faster than that of NAC.