摘要
通过自密实包浆再生骨料混凝土力学性能及快速冻融循环试验,从试件的抗压强度、劈裂抗拉强度、抗折强度及冻融后试件的质量损失率、抗压强度损失率及相对动弹性模量角度研究了再生粗骨料包浆对自密实再生混凝土性能的影响,结合SEM电镜试验从微观上分析了骨料包浆对混凝土抗冻性能的改善机制。结果表明:普通混凝土和再生混凝土的劈裂抗拉强度、抗折强度与抗压强度之间的换算关系式不适用于自密实包浆再生骨料混凝土,提出的新关系式与试验数据较吻合;再生粗骨料包浆优化了骨料物理性能,改善了混凝土新旧界面过渡区,增强了其密实性,提高了混凝土的抗冻性能;采用42.5R水泥浆对骨料进行包浆时,混凝土的抗冻性能最优,虽不及普通混凝土,但与骨料未包浆的混凝土相比,150次冻融循环后混凝土相对动弹性模量提高了18.6%;基于冻融后抗压强度和相对动弹性模量建立的冻融损伤模型拟合精度较高,能较好地反映自密实包浆再生骨料混凝土的冻融损伤破坏规律。
Through the mechanical properties and rapid freeze-thaw cycle test of self compacting recycled aggregate concrete,the influence of recycled coarse aggregate slurry on the properties of self compacting recycled aggregate concrete is studied from the aspects of compressive strength,splitting tensile strength and flexural strength,mass loss rate,compressive strength loss rate and relative dynamic elastic modulus of specimens after freeze-thaw.Combined with SEM electron microscopy test,the mechanism of improving the frost resistance of concrete by wrapped slurry aggregate is analyzed microscopically.The results show that,the conversion relationship between the split tensile strength,flexural strength and compressive strength of ordinary concrete and recycled concrete is not applicable to self-compacting wrapped slurry recycled aggregate concrete and the new relationship proposed in this paper is in good agreement with the experimental data.Wrapped slurry recycled coarse aggregate optimizes the physical performance of the aggregate,improves the transition area between the old and new concrete interfaces,enhances its compactness,and improves the frost resistance.When 42.5R cement slurry is used to wrap the aggregate,the frost resistance of concrete is the best.Although it is not as good as ordinary concrete,the relative dynamic elastic modulus of concrete increases by 18.6%after 150 cycles of freeze-thaw compared with the concrete of aggregate without wrapping slurry.The freeze-thaw damage model established based on the compressive strength and relative dynamic elastic modulus after freeze-thaw has a higher fitting accuracy,and can better reflect the freeze-thaw damage failure law of self-compacting wrapped slurry recycled aggregate concrete.
作者
曹鑫铖
金宝宏
侯玉飞
CAO Xincheng;JIN Baohong;HOU Yufei(College of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, P. R. China;Department of Engineering and Applied Sciences, Xinhua College of Ningxia University, Yinchuan 750021, P. R. China)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2022年第1期149-159,共11页
Journal of Civil and Environmental Engineering
基金
宁夏高等学校科学研究项目(NGY2020103)。
关键词
自密实再生混凝土
包浆
力学性能
冻融循环
冻融损伤模型
微观结构
self-compacting recycled concrete
wrapped slurry
mechanical properties
freezing and thawing cycles
freeze-thaw damage model
microstructure
