[关键词]
[摘要]
根据大型渠道衬砌混凝土的结构特点和所处的环境,通过试验研究了水泥种类、粉煤灰、纤维对衬砌混凝土收缩(塑性收缩、干缩、自收缩)性能的影响规律。试验结果表明:在配合比中掺入优质粉煤灰,可有效降低混凝土的收缩;在配合比中掺入纤维,混凝土的抗收缩能力进一步提高;与P·C32.5水泥相比, P·O42.5水泥具有更好的抗收缩性能;在配合比中掺入优质粉煤灰、纤维、使用P·O42.5水泥,可使相同强度等级的混凝土具有更好的抗裂性。最后根据各类收缩裂缝特征及影响因素,提出了预防渠道衬砌混凝土裂缝的措施。
[Key word]
[Abstract]
We analyzed the impacts of cement type, fly ash, and fiber on the shrinkage of lining concrete according to the structural features and situation of large channel lining concrete, and the shrinkage included plastic shrinkage,drying shrinkage, and autogenous shrinkage. The results showed that (1) the concrete shrinkage reduces effectively with high-quality fly ash adding into the concrete mixture; (2) the shrinkage resistance of concrete improves with fiber adding into the concrete mixture; (3) P·O42.5 cement has higher shrinkage resistance than P·C32.5 cement; and (4) the concrete has high crack resistance with high-quality fly ash and fiber adding into concrete and the usage of P·O42.5 cement. In order to prevent the channel concrete cracks, several recommendations were proposed according to the characteristics and impact factors of different cracks.
[中图分类号]
[基金项目]
中央级公益性科研院所基本科研业务费专项资金重点项目(Y412001、Y412005)