再生细骨料对混凝土塑性收缩开裂性能影响

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发布时间：2021-10-29

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参考国际建筑官员协会 ICBO 标准，采用平板约束试验、自制的混凝土塑性应力测试装置以
及压汞法，分析了再生细骨料粒径、取代率以及混凝土水灰比、砂率等对再生细骨料混凝土塑性应
力、孔结构及塑性收缩开裂性能的影响．结果表明：随着再生细骨料粒径范围的减小，再生细骨料
混凝土塑性收缩开裂风险逐渐降低；再生细骨料取代率的增加，使得再生混凝土塑性收缩开裂风
险增大；再生细骨料混凝土水灰比对其抗塑性收缩开裂性能至关重要，过大或过小均会提高其塑
性收缩开裂风险；选择适当的砂率可以控制再生细骨料混凝土的塑性收缩开裂程度．
关键词：塑性收缩应力；再生细骨料；开裂性能；粒径；孔结构
中图分类号：TU528．041 文献标志码：A doi：lO．3969／j．issn．1007—9629．2014．03．019
Effect of Recycled Fine Aggregate on Plastic Shrinkage
Cracking Properties of Concrete
SUN Jiaying ， XIAO Tianxiang ， LU Yangsheng
(1．Research Center of Green Building M aterials and Resources Reuse，Ningbo Institute of Technology，
Zhejiang University，Ningbo 315100，China；2．Zheiiang Chicheng Co．Ltd．，Dongyang 322100，China)
Abstract：Taking ICBO standard as a reference and using the flat panel constraint test，self-developed con—
crete plastic stress testing device and mercury intrusion method，the effects of recycled fine aggregate par—
ticle size，replacem ent rate，water—cement ratio，sand ratio on the plastic stress，pore structure and the
property of plastic shrinkage cracking were investigated． The results show that the risk of cracking of the
recycled fine aggregate concrete reduces gradually with decreasing recycled fine aggregate particle size
range and increases with increasing replacement ratio of recycled fine aggregate．The water—cement ratio of
recycled fine aggregate concrete is of great importance to the crack resistance of the concrete，either too
high or too low would increase the risk of cracking． Appropriate sand ratio can be chosen to control the
cracking of recycled fine aggregate concrete．
Key words：plastic shrinkage stress；recycled fine aggregate；cracking performance；particle size；pore struc—
t11re
在生产再生混凝土骨料过程中，会产生 2O 左
右粒径小于 4．75 mm 的细颗粒，对这些细颗粒进行
深加工处理后可产生粒径为 0．15～ 4．75 mm 的再
生细骨料，用其替代部分天然砂可配制再生细骨料
混凝土．但是再生细骨料会使混凝土性能与同配合
比普通混凝土存在较大的差异．国内外学者对再生
细骨料混凝土的力学性能、耐久性能等方面作了一
定的研究，提出了相应的措施，并取得了一定的
成果。，然而针对再生细骨料对混凝土塑性收缩
开裂影响的研究较少．由于混凝土塑性开裂会影响