汪建群 方志 邓波 马占飞 祝明桥

摘要：粉煤灰对高强混凝土收缩徐变的影响直接关系到结构长期性能的合理确定。制作粉煤灰掺量分别为0、12%和24%的100 mm×100 mm×400 mm的C50混凝土棱柱体试件，在试验室条件下进行收缩及不同加载龄期的徐变试验，研究了粉煤灰对高强混凝土收缩徐变的影响。根据试验结果评估了目前常用的4种相关规范公式对高强混凝土收缩徐变的适用性，并引入粉煤灰影响系数以综合反映粉煤灰掺量和加载龄期对高强混凝土收缩徐变的影响，根据试验结果和现有研究成果提出了其修正模型。分析结果表明，JTG D 62和GL 2000推荐的收缩徐变预测模式与基准试件实测结果较为吻合，验证结论亦说明所引入的粉煤灰影响系数可应用于掺粉煤灰高强混凝土的收缩徐变预测。

关键词：粉煤灰；高强混凝土；收缩；徐变；长期性能

中图分类号：TU528.31

文献标志码：A 文章编号：1674-4764（2016）03-0110-08

Abstract： The shrinkage and creep of high strength concrete was affected by the mixed fly ash. The influence was directly related to the long-term behavior of structures. The shrinkage and creep experiment of C50 concrete with fly ash content 0， 12%， 24% were conducted with 100 mm×100 mm×400 mm prism specimens in the laboratory. Four kinds of current commonly used specifications for the shrinkage and creep of high strength concrete were assessed. With the experiment results and other existing research referenced， the fly ash influence coefficient and its correction model were introduced to reflect the influence of different load age and fly ash content. The analysis showed that the shrinkage and creep mode recommended from JTG D62 and GL 2000 agreed well with the measured results form the reference specimens. And the verification conclusion demonstrated that the introduced fly ash influence coefficient could be applied to the shrinkage and creep of high strength concrete with fly ash.

Keywords：fly ash； high strength concrete； shrinkage； creep； long-term behavior

粉煤灰作为矿物掺合料掺入到高强混凝土中，在早期可改善混凝土的泵送性能并降低其水化热，在后期又可增强结构的耐久性[1]。粉煤灰在高强混凝土结构如桥梁工程中的应用极为普遍，可以实现变废为宝，有利于环境保护。但掺粉煤灰高强混凝土的收缩徐变较难预测，一方面是由于早期提出的收缩徐变模式对于高强混凝土的适用性值得商榷；此外，粉煤灰的掺入改变了混凝土的配合比，其收缩徐变亦受到影响[2]。

目前常用的收缩徐变预测模型如JTG D 62—2004[3]、GL 2000[4]、ACI 209R[5]、AASHTO[6]以及B3[7]模型均未考虑粉煤灰的影响。……