摘要
基于180 d设计龄期,采用高掺粉煤灰技术制备了C18015和C18020三级配碾压混凝土,测试和分析了其宏观性能和微观结构。研究结果表明两种碾压混凝土均满足设计要求。两种碾压混凝土的早期强度较低,但后期增幅较大,28、90、180 d龄期强度增长比例大致为1∶（1.4-1.6）∶（1.7-1.9）。同时,由于胶凝材料用量较少且粉煤灰掺量较高,大大降低了碾压混凝土的干缩和绝热温升,改善了抗裂性能。90d后粉煤灰的火山灰作用变得显著, Ca（OH）2被大量消耗并生成水化硅酸钙等水化产物,使得浆体微结构更为致密,进而提高混凝土后期强度。
The three-grade roller compacted concretes with strength grade of C18015 and C18020 are prepared with high volume fly ash technique based on design age of 180 days respectively, and their properties and microstructure are tested and analyzed. The testing results show that the strength of two roller compacted concretes meet design requirements. The early strengths of two kinds of concretes are low, but increase rapidly at later. The strength ratio at 28, 90 and 180 days is roughly 1：（1.4-1.6）：（1.7-1.9）. At the same time, because of less dosage of cementitious materials and higher content of fly ash, the drying shrinkage and adiabatic temperature rise of roller compacted concrete reduce greatly, which is beneficial to improve its cracking resistance. The pozzolnaic effect of fly ash becomes strong after 90 days hydration, which causes the consumption of a large number of calcium hydroxide and the formation of calcium silicate hydrates, and leads to a denser paste microstructure which is beneficial to improve the later strength of concrete.
出处
《水力发电》
北大核心
2015年第3期96-100,共5页
Water Power
基金
硅酸盐建筑材料国家重点实验室开放基金资助课题(SYSJJ2012-11)
湖北工业大学校博士基金(BSQD12055)
湖北省桥梁安全监控技术与装备工程技术研究中心开放基金(QLZX2014016)
关键词
碾压混凝土
粉煤灰
龄期
性能
微观结构
roller compacted concrete
fly ash
age
property
microstructure
