Experimental Study On Statistical Characteristics And Mechanical Properties Of Recycled Concrete

In this paper,the influence of water absorption,cement content,water cement ratio and water reducing agent on compressive strength of recycled concrete was investigated,The main influencing factors of compressive strength of recycled aggregate concrete based on red brick are analyzed.Found by water absorption test: The water absorption and water absorption rate of recycled aggregate are much higher than that of natural aggregate,The maximum water absorption of recycled coarse aggregate(5-31.5mm)is 5%-12%.The water absorption rate of recycled coarse aggregate is much higher than that of natural aggregate,The water absorption rate of the former 5min is the largest,and the water absorption rate decreases after 5min.The water absorption rate of 5min recycled coarse aggregate is about 90% of the saturated water absorption rate.Through the single factor change to optimize the matching parameters,the final determination,cement content,water cement ratio of 20%-22.6%,0.53-0.62,recycled coarse and fine aggregate percentage is 1:5,the cement content is 22.6%,water cement ratio of 0.56 groups,the compressive strength of high strength,good stability.Than under the same conditions with recycled concrete,adding naphthalene superplasticizer a group of specimens of 3D,7d,28 d compressive strength ratio is higher than the standard group and the incorporation of polycarboxylate superplasticizer group.And the age strength is more stableRecycled aggregate in mixing before adding additional water to the saturated surface dry aggregate,recycled concrete specimens made of 28 d compressive strength is lower than that without adding additional water compressive strength of about13.1%.28 d strength near the specimen strength and good stability.The addition of additional water in the optimum proportion can not improve the compressive strength of recycled concrete.The uniaxial compressive stress-strain test showed that the peak strain of recycled concrete was about 25% higher than that of ordinary concrete.Under the condition of the same rate of loading,the ultimate peak strain of the reversed segment tends to be stable.In the process of compression failure,the elastic modulus of therising section of the construction waste recycled concrete block under the same age and different loading rate is not the same as the mix design parameter.