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完成了0%,30%,50%,70%,100%再生粗骨料取代率下混凝土的弹性模量、湿热变形性能以及不同龄期的收缩率测试,分析了影响再生混凝土干缩性能的因素。研究结果表明,不同取代率的再生混凝土早期收缩率差值并不明显,收缩量与再生粗骨料取代率也无明显相关性,40~50d后,随着再生粗骨料取代率的提高,再生混凝土的干缩率显著增加,与天然混凝土收缩率之间的差值开始扩大,50~220d是再生混凝土与天然混凝土收缩率差距扩大的主要阶段,100%取代率再生混凝土和天然混凝土收缩率的差距由50d的1.4倍增加到220d的2.4倍;再生粗骨料取代率越高的再生混凝土收缩趋于稳定的龄期越长;再生混凝土的热胀率、吸水膨胀率随着再生粗骨料取代率的增加明显增大。除了水灰比等常规因素外,再生粗骨料中旧砂浆含量对再生混凝土变形性能的实际影响最大,并通过颗粒级配、再生粗骨料取代率等反映出来,实际工程中应合理控制再生粗骨料取代率以及小粒径再生粗骨料的比重。
The concrete elastic modulus, wet-heat deformation performance and shrinkage at different ages were tested under 0%, 30%, 50%, 70% and 100% recycled coarse aggregate substitution rate. The influence of shrinkage on the shrinkage of recycled concrete factor. The results show that the difference of early shrinkage of recycled concrete with different substitution rates is not obvious, and there is no significant correlation between the shrinkage and the replacement rate of recycled coarse aggregate. After 40 ~ 50d, with the increase of replacement rate of recycled coarse aggregate, The shrinkage rate of recycled concrete increased significantly, and the difference with the shrinkage of natural concrete began to expand. The difference between shrinkage of recycled concrete and natural concrete was 50 ~ 220d. The shrinkage of recycled concrete and natural concrete was 100% Of the recycled concrete increased from 1.4 times of 50d to 2.4 times of that of 220d.The recycled concrete with higher replacement rate of recycled coarse aggregate tended to be stable and the aging period was longer.The thermal expansion coefficient and water absorption expansion coefficient of recycled concrete increased with the regeneration of coarse bone The increase of material substitution rate obviously increases. In addition to conventional factors such as water-cement ratio, the actual effect of the content of old mortar in recycled coarse aggregate on the deformability of recycled concrete is the greatest, and the particle gradation and the replacement rate of recycled coarse aggregate are reflected. In practice, the regeneration should be controlled reasonably Coarse aggregate replacement rate and the proportion of small size recycled coarse aggregate.