模拟再生粗骨料及再生混凝土的制备与性能研究

Investigation on the preparation and properties of simulated recycled coarse aggregate and recycled concrete

为提高废弃混凝土资源化利用率,使用再生骨料制备再生混凝土,解决废弃混凝土的资源与环境问题。针对再生骨料来源复杂,采用三种不同强度等级的原生混凝土模拟制备再生粗骨料,测试其物理性能,分析其所制备混凝土的力学性能与耐久性能。试验结果表明:原生混凝土经过破碎加工处理后所制得的再生骨料,与天然再生粗骨料物理性能相当,然而,相较于天然骨料,其吸水率和压碎指标较大,而堆积密度和表观密度较小。再生粗骨料制得的混凝土的立方体抗压强度、轴心抗压强度与弹性模量相较于天然混凝土有所下降,而电通量有所提升。原生混凝土强度等级越高,骨料与水泥浆体的粘结性越好,制得的再生粗骨料表面粘附着越多的残余砂浆,使得再生粗骨料的物理性能下降,进而影响了再生混凝土的力学性能与耐久性。

In order to improve the resource utilization rate of waste concrete,recycled aggregate is used to prepare recycled concrete to solve the resource and environmental problems of waste concrete.Considering the complex source of recycled aggregate,three different strength grades of native concrete were used to simulate the preparation of recycled coarse aggregate,the physical properties were measured,and the mechanical properties and durability of prepared concrete were analyzed.The test results showed that the recycled aggregate prepared from native concrete through crushing processing had the similar physical properties as natural recycled coarse aggregate.However,compared with natural aggregate,the water absorption and crushing index were larger,while the bulk density and apparent density are smaller.Compared with natural concrete,the cube compressive strength,axial compressive strength and elastic modulus of concrete made of recycled coarse aggregate decreased,while the electric flux increased.The higher the strength grade of native concrete,the higher the adhesion between aggregate and cement mortar,and the more residual mortar is attached to the surface of recycled coarse aggregate,which makes the physical properties of recycled coarse aggregate poor,and then affects the mechanical properties and durability of recycled concrete.