不同粒级再生骨料取代的混凝土基本性能试验研究

Experimental Research on Basic Properties of Concrete with Replacement of Different Size Fractions of Recycled Aggregate

采用同一来源混凝土制备不同粒级的再生骨料,研究其对混凝土工作性、力学性能、抗裂性和干燥收缩的影响。再生骨料降低混凝流动性,改善粘聚性和保水性,粒级越细影响越大。再生骨料使抗压强度和劈裂抗拉强度有不同程度降低,粒级增大强度下降越少,但对抗折强度的影响不大。再生骨料可以抑制早期塑性开裂,取代粒级越小、取代范围越大,效果越显著。长龄期的干燥收缩随取代粒级减小和取代范围增大而增大。

Different size fractions of recycled aggregate that are derived from the same concrete were prepared. The effects of the recycled aggregate to the workability, mechanical property, crack resistance and drying shrinkage of the concrete were studied. The results indicated that the recycled aggregate could reduce the mobility, while the cohesiveness and water-retaining were improved, the effects increased with the decrease of the size fractions. The compressive strength and split tensile strength had different degrees of decline with the replacement of recycled aggregate, the effects decreased with the increase of the size fractions. That has little effects to the flexural strength. The recycled aggregate can restrain the cracking, the effects increased with the decrease of the size fractions and the expanding of the replacement range. The long-age drying shrinkage increased with the decrease of the size fractions and the expanding of the replacement range.