不同吸水率粗骨料对混凝土强度和干燥收缩性能的影响

Effect of Coarse Aggregate with Different Water Absorption on Strength and Drying Shrinkage of Concrete

试验以不同吸水率粗骨料(天然碎石、再生骨料、煤矸石骨料)配制C20、C30混凝土,对不同吸水率粗骨料混凝土抗压强度及抵抗干燥收缩性能进行基础性试验研究,阐明不同吸水率粗骨料所保有的水分对混凝土强度及干燥收缩性能的影响。试验结果表明,随着养护龄期的增加,不同吸水率、不同强度等级混凝土的抗压强度也随之增加;和天然混凝土对比分析来看,再生粗骨料混凝土与自燃煤矸石粗骨料混凝土的强度略有下降。当混凝土强度等级相同时,在7 d以内相对较短干燥收缩龄期时内吸水率最大的自燃煤矸石混凝土的干燥收缩长度变化率反而最小,再生粗骨料混凝土试件次之,普通混凝土试件的干燥收缩率最大;但7 d以后随着干燥收缩龄期的增加,吸水率最大的自燃煤矸石混凝土的干燥收缩长度变化率却最大,所对应的质量损失率也会加大。

Making C20 ,C30 concrete with different water absorption of coarse aggregate（natural crushed stone ,recycled aggregate, coal gangue aggregate ） , the fundamental experiment was used to study the compressive strength and drying shrinkage performance of coarse aggregate concrete with different water absorption, illustrating the effect of different water absorption of coarse aggregate on concrete strength and drying shrinkage. Results show that, when the curing age increases, the compressive strength of concrete with different water absorption and different strength grade increases. Compared with natural concrete, the strength of recycled coarse aggregate concrete and spontaneous combustion coal gangue coarse aggregate concrete decrease slightly. When the concrete strength grade is the same, within 7 d relative shorter drying shrinkage age,when the water absorption rate of spontaneous combustion coal gangue coarse aggregate concrete is the maximum, the drying shrinkage length is minimum, the recycled coarse aggregate concrete is the second place,and the ordinary concrete is biggest. But after 7 d,when the age of drying shrinkage increases,the rate of dry shrinkage of spontaneous combustion coal gangue coarse aggregate concrete with the maximum water absorption rate is maximum, and the corresponding quality loss rate will increase.