等强度条件下粉煤灰对补偿收缩混凝土变形性能的影响  

Influence of Fly Ash on the Deformation of Shrinkage-compensating Concrete with the Same Level of Strength

作　　者：苗苗[1] 米贵东[1] 阎培渝[1] 

机构地区：[1]清华大学土木工程系土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《硅酸盐通报》2012年第3期501-505,共5页Bulletin of the Chinese Ceramic Society

基　　金：NSFC-广东联合基金重点项目(U1134008)

摘　　要：通过测定水中限制膨胀率和水养7 d转干空后的限制膨胀率,计算干燥收缩落差,讨论粉煤灰在等强度条件下对补偿收缩混凝土变形性能的影响。结果表明:等强度条件下掺加适量粉煤灰可以明显地促进限制膨胀率的增长;掺量过大容易导致早期约束不足,降低对限制膨胀的促进作用。粉煤灰可以明显降低混凝土转干空后早期的干燥收缩落差。随着粉煤灰掺量增加,干燥收缩落差进一步降低,空气中放置28 d后均表现为膨胀。对于硫铝酸钙-氧化钙类膨胀剂和粉煤灰复掺的补偿收缩混凝土,膨胀剂最小用量的要求可以适当降低。Percentages of restrained expansion of shrinkage-compensating concrete cured moistly and dryly after 7 d moist curing were investigated, and variation of expansion decline was calculated to discuss the effect of fly ash on the deformation of shrinkage-compensating concrete with the same level of strength. The results show that fly ash can improve the expansion of concrete cured moistly, proper amount of fly ash can significantly increase expansion but with large amount of fly ash, the growth variation of expansion drops due to insufficient internal restraint. Fly ash can reduce the expansion decline within 7 d dry curing, with the dosage of fly ash rising, the expansion decline is further reduced. The concretes with fly ash cured dryly for 28 d are still expansive. For concrete with calcium sulphoaluminate hydrate- calcium hydroxide expansive agent and fly ash, smaller addition percentage of expansive agent in binding materials based on the national standard is recommended.

关 键 词：补偿收缩混凝土 粉煤灰 HCSA膨胀剂 限制膨胀率 强度 

分 类 号：TU528[建筑科学—建筑技术科学]