颗粒整形对再生骨料混凝土耐久性的影响

The affection by aggregate-shaping on durability of the recycled aggregate concrete

简单破碎再生骨料粘附着大量水泥石,并且在破碎过程中产生大量微裂缝,因此简单破碎再生骨料混凝土的需水量大,导致混凝土的收缩大、氯离子渗透系数大、碳化速度快以及抗冻性差。颗粒整形不仅除去了骨料表面粘附的水泥石,而且使得再生骨料变得圆滑,混凝土需水量显著降低,混凝土的收缩性能、抗氯离子渗透性、抗碳化性能和抗冻性能均显著改善,拓宽了再生混凝土的应用领域。

Compared with natural aggregate, simply-fragmented recycled aggregate has many disadvantages. For example, it has a lot of cement mortar on its surface, and many micro cracks are created in the simply-fragmented recycled aggregate during the fragmenting process. Therefore, simply-fragmented recycled aggregate concrete will need more water, which leads to its greater shrinkage, greater factors of chloride penetration, faster speed of carbonation and poor performance of anti-freezing-and-thawing. But aggregate reshaping would not only eliminate much of the cement mortar attaching to the surfaces of the aggregate but also make simply-fragmented aggregate smooth. As a result, concrete with the reshaped simply-fragment recycled aggregate need much less water and has smaller shrinkage. And anti-chloride-penetration, anti-carbonation and anti-freezing-and-thawing of the concrete with the reshaped simply-fragmented recycled aggregate will greatly improve. Therefore the recycled concrete's using field will be broaden.