包浆再生粗骨料对自密实混凝土力学性能及抗冻性的影响

通过自密实包浆再生骨料混凝土力学性能及快速冻融循环试验,从试件的抗压强度、劈裂抗拉强度、抗折强度及冻融后试件的质量损失率、抗压强度损失率及相对动弹性模量角度研究了再生粗骨料包浆对自密实再生混凝土性能的影响,结合SEM电镜试验从微观上分析了骨料包浆对混凝土抗冻性能的改善机制.结果 表明:普通混凝土和再生混凝土的劈裂抗拉强...

Experimental study on the effect of the wrapped slurry recycled coarse aggregate on the mechanical properties and frost resistance of self-compacting concrete

Through the mechanical properties and rapid freeze-thaw cycle test of self compacting recycled aggregate concrete, the influence of recycled coarse aggregate slurry on the properties of self compacting recycled aggregate concrete is studied from the aspects of compressive strength, splitting tensile strength and flexural strength, mass loss rate, compressive strength loss rate and relative dynamic elastic modulus of specimens after freeze-thaw. Combined with SEM electron microscopy test, the mechanism of improving the frost resistance of concrete by wrapped slurry aggregate is analyzed microscopically.The results show that, the conversion relationship between the split tensile strength, flexural strength and compressive strength of ordinary concrete and recycled concrete is not applicable to self-compacting wrapped slurry recycled aggregate concrete and the new relationship proposed in this paper is in good agreement with the experimental data.Wrapped slurry recycled coarse aggregate optimizes the physical performance of the aggregate, improves the transition area between the old and new concrete interfaces, enhances its compactness, and improves the frost resistance.When 42.5R cement slurry is used to wrap the aggregate, the frost resistance of concrete is the best. Although it is not as good as ordinary concrete, the relative dynamic elastic modulus of concrete increases by 18.6% after 150 cycles of freeze-thaw compared with the concrete of aggregate without wrapping slurry.The freeze-thaw damage model established based on the compressive strength and relative dynamic elastic modulus after freeze-thaw has a higher fitting accuracy, and can better reflect the freeze-thaw damage failure law of self-compacting wrapped slurry recycled aggregate concrete.