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试验以不同环境、不同再生粗骨料置换率为变量对C30再生混凝土抵抗干燥收缩裂缝性能进行了基础性试验研究,并与普通混凝土试件进行对比。试验结果表明,在相对湿度(RH60%)相同条件下,再生混凝土与普通混凝土随着干燥环境温度的提高,自由干燥收缩长度变化率逐渐加大;在相同干燥温度条件下,随着再生粗骨料置换率的增加,混凝土自由干燥收缩率也会加大;在环境相对湿度(RH60%)相同条件下,混凝土的干燥温度越高,早期干燥收缩裂缝产生的龄期就越早;在混凝土干燥温度相同条件下,再生粗骨料置换率越大,早期干燥收缩裂缝产生的龄期就越早,再生粗骨料的置换率对再生混凝土极限抗拉强度的影响有限。
The experiments were conducted to study the properties of C30 recycled concrete against drying and shrinkage cracking based on the different environment and the different replacement rates of recycled coarse aggregate. The experimental results were compared with that of ordinary concrete specimens. The experimental results show that under the same conditions of relative humidity (RH60%), the change rate of free-drying shrinkage length increases with the increase of drying ambient temperature under the same conditions of recycled concrete and ordinary concrete. With the same drying temperature, In the condition of the same relative humidity (RH60%), the higher the drying temperature of concrete, the earlier the age of dry shrinkage cracks will occur. In the concrete dry Under the same temperature conditions, the larger the replacement rate of recycled coarse aggregate, the earlier the age of dry shrinkage cracks will occur, and the replacement ratio of recycled coarse aggregate will have a limited impact on the ultimate tensile strength of recycled concrete.