再生粗骨料混凝土早期收缩性能试验研究

Experimental research on early shrinkage of recycled coarse aggregate concrete

通过试验研究水灰比、再生粗骨料取代率、减水剂和粉煤灰对再生混凝土早期干缩性能的影响。研究结果表明再生混凝土的早期干缩率和失水率均随着水灰比和取代率的增大而增大;再生混凝土在龄期7d内干缩速率和失水速率最大;掺入减水剂和粉煤灰可以有效地控制再生混凝土的干缩。根据试验结果建立了再生粗骨料取代率为100%的再生混凝土早期干缩计算模型,该模型计算结果与他人试验结果吻合较好。

The influences of water-cement ratio,replacement ratio of recycled coarse aggregate,water reducer and fly ash on early drying shrinkage of recycled concrete were investigated by experiments.Research results show that the shrinkage ratio and the water loss ratio of recycled concrete increase with the water- cement ratio and replacement ratio of recycled coarse aggregate,the rates of the shrinkage and water loss reach to the maximum in the first 7 days,and water reducer and fly ash could effectively reduced the shrinkage of recycled concrete.The model for drying shrinkage of recycled concrete with 100%replacement of the recycled coarse aggregate is established according to experiment results,and the calculated values of the shrinkage ratio of recycled coarse aggregate concrete are in good agreement with the test values obtained by other researchers.