预湿火山石骨料对混凝土强度及收缩性能的影响

The influence of prewet volcanic aggregate on the strength and shrinkage performance of concrete

分别采用腾冲火山石和石灰石作为骨料制备C30、C40两种强度等级的混凝土,对比研究了预湿前后火山石混凝土与石灰石混凝土拌合物性能、抗压强度及收缩性能。结果表明,通过适当增加减水剂掺量能使火山石混凝土获得较大的坍落度和扩展度;相同配合比下,火山石混凝土抗压强度要高于石灰石混凝土,早期自收缩、长期干燥收缩的收缩率较石灰石混凝土大,而通过预湿火山石骨料,在相当的工作性能下,可以有效减少火山石混凝土中减水剂用量,降低早期自收缩及长期干燥收缩。

In this paper,Tengchong volcanic rock and limestone are used as aggregates to prepare C30 and C40 concrete,and the performance,compressive strength and shrinkage of the mixture of volcanic rock concrete and limestone concrete before and after pre-wetting are compared.The results show that the volcanic rock concrete can achieve greater slump and expansion by properly increasing the amount of admixture.Under the same mix ratio,the compressive strength of volcanic rock is higher than that of limestone concrete,and the shrinkage rate of early autogenous shrinkage and long-term dry shrinkage is higher than that of limestone concrete.However,by pre-wetting the volcanic rock aggregate,under the same working performance,it can effectively reduce the amount of water reducing agent used in volcanic stone concrete,reduce early autogenous shrinkage and long-term dry shrinkage.