再生粗骨料粒径对再生混凝土早期开裂影响研究

采用平板约束试验方法,对5~15 mm、15~25 mm、25~31.5 mm三种级别再生粗骨料粒径的再生混凝土(RC)和粉煤灰再生混凝土(FRC)分别进行早期抗裂性能(龄期:0~24 h)试验研究。研究结果表明:在三种粗骨料粒径级别范围内,25~31.5 mm级别再生混凝土试件的早期开裂损伤最小;而对粉煤灰掺入量为15%的粉煤灰再生混凝土来说,粒径级别为15~25 mm的早期开裂损伤最小,表明粉煤灰掺入量与粗骨料粒径之间存在一个优化掺入量,在这个优化掺入量情况下,粉煤灰再生混凝土的早期抗开裂性能能够达到比较理想的效果。

Effects of recycled coarse aggregate size on early anti-crack performance of recycled aggregate concrete

Early age cracking has been an everpresent problem during the application of recycling coarse aggregate concrete. Influences of recycling coarse aggregate size (5~15mm, 15~25mm and 25~31.5mm) on early age (age: 0~24h) cracking tendency of recycling coarse aggregate concrete (RC) and recycling coarse aggregate concrete with fly ash (FRC) were studied based on slab test method. The results of the early age cracking indexes and cracking processes indicate that the large aggregate size (25~31.5mm) corresponds to the decrease of cracking damage for recycling coarse aggregate concrete targets, the slab test samples with 15-25mm of recycling coarse aggregate size has the optimum efficiency in terms of anti-cracking ability when comparing to the other two kinds of FRC samples for RC samples with 15% fly ash. The experimental result in this paper is very beneficial to the optimization and design of recycling coarse aggregate concrete on anti-cracking mix proportions.