摘要
对等量替代双掺粉煤灰、硅灰的高性能混凝土进行了强度、坍落度及单面干燥养护条件下的3 d早期收缩试验研究,分析了双掺比例(1∶1、2∶1、5∶1)及双掺总量(22.5%、30%、45%)对混凝土性能的影响。试验结果表明:在双掺总量(30%)不变时,随着FA/SF的增加,3、28 d强度逐渐降低,且28 d强度降低程度均小于3 d,初凝时间增加,但用坍落度衡量的和易性有所提高,早期收缩逐渐降低;在双掺比例(2∶1)不变时,随着双掺总量的增加,坍落度降低,初凝时间缩短,3、28 d强度有所降低,且28 d强度降低程度亦均小于3 d,早期收缩逐渐降低,尤其是双掺总量达到45%时,强度降低程度尤为明显。在按FA/SF为2∶1单独增加的情况下,单独增加粉煤灰降低早期收缩效果比单独增加硅灰增大早期收缩更为明显。
It studies strength,slump and the 3 d early shrinkage under the condition of single-side dry curing of high performance concrete with fly ash and silica fume.The influence of the ratio of double admixture(1∶1,2∶1,5∶1)and the total amount of double admixture(22.5%,30%,45%)on the concrete properties is analyzed.The results show that when the total amount of double admixture(30%)is contant,the 3,28 d strength and the early shrinkage decreases gradually with the increase of FA/SF,and the strength reduction degree of 28 d is less than 3 d,but the initial setting time and the workability measured by slump increases.When the ratio of double admixture(2∶1)is constant,with the increase of the total amount of double admixture,the 3 d and 28 d strength,slump and the early shrinkage decreases gradually,the initial setting time is shortened,and the strength reduction degree of 28 d is less than 3 d also,especially when the total amount of double admixture reaches 45%,the reduction degree decreases significantly.When the ratio of FA/SF is 2∶1,the effect of reducing early shrinkage by adding fly ash alone is more obvious than increasing that by adding silica fume alone.
作者
李彪
钱晓倩
林天乐
钱匡亮
LI Biao;QIAN Xiaoqian;LIN Tianle;QIAN Kuangliang(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)
出处
《混凝土》
CAS
北大核心
2022年第12期29-32,43,共5页
Concrete
关键词
双掺比例
双掺总量
强度
坍落度
混凝土早期收缩
ratio of double admixture
total amount of double admixture
strength
slump
early shrinkage of concrete
