再生骨料作为内养护介质对高性能混凝土性能的影响

Effect of recycled aggregate as internal curing medium on the properties of high-performance concrete

研究了用再生骨料作为内养护的介质,在吸水饱和条件下取代不同比例的天然粗骨料对混凝土坍落度、28 d力学性能、自收缩、抗氯离子渗透及内部相对湿度和孔结构的影响。试验结果表明,再生骨料的取代量对混凝土的工作性能几乎没有影响,取代量小于20%时,对混凝土的力学性能影响较小,超过30%以后,混凝土的力学性能降低较为显著。混凝土的自收缩随混凝土中再生骨料含量的增加而降低,最高相比基准组减少了24.7%。再生骨料能在一定程度上提高混凝土的抗氯离子渗透性能。此外,混凝土中再生骨料的用量越多,混凝土的内部相对湿度越大,孔隙率越低,孔径越小。

The effects of recycled aggregate on the workability, 28 d mechanical properties, autogenous shrinkage, chloride penetration resistance, internal relative humidity and pore structure of high-performance concrete were studied by replacing different proportion of natural coarse aggregate with recycled aggregate(saturated water absorption condition).The obtained results show that the proportion of recycled aggregate had little influence on the workability of the concrete.When the replacement ratio of recycled aggregate was less than 20%,it also had a little effect on the mechanical performance of the concrete.While its ratio was more than 30%,the mechanical performance of concrete decreased significantly.The autogenous shrinkage of concrete decreased with the increase of recycled aggregate content and the maximum reduction was 24.7% when compared to the base group.Recycled aggregate can improve chloride penetration resistance of concrete.In addition, the higher the amount of recycled aggregate in concrete, the higher the internal relative humidity, the lower the porosity and the finer the pore size of concrete.