预浸石灰水碳化再生粗骨料混凝土的力学性能

Mechanical Properties of Recycled Coarse Aggregate Concrete with Pre-soaking in Lime Water and Carbonated Aggregates

采用预浸石灰水碳化法对再生粗骨料进行强化处理,对强化前后再生粗骨料物理性能进行检测,研究了碳化再生粗骨料对混凝土力学性能的影响.同时结合微观测试手段,分析碳化对再生粗骨料的增强机理.通过立方体抗压、劈裂抗拉及抗折强度试验,研究强化后混凝土各龄期强度变化.结果表明:预浸石灰水碳化法能够显著改善再生粗骨料的物理性能,其吸水率降低15.2%~22.9%,压碎值降低15.2%~17.7%;碳化后粗骨料的界面过渡区更加密实,有利于再生粗骨料品质的提升;7、28 d的混凝土强度随粗骨料取代率的增大而降低;当粗骨料取代率为50%时,预浸石灰水碳化再生混凝土强度与普通混凝土相当.

The recycled coarse aggregates were strengthened by pre-soaking lime water combined with accelerated carbonation,the physical property of recycled coarse aggregates were tested.The effect of carbonated recycled coarse aggregates on the mechanical properties of recycled concrete was investigated,and the strengthening mechanism of carbonation was also analyzed by microscopic testing means.The strength changes of modified recycled concrete at various ages were studied by cubic compressive,splitting tensile and flexural strength tests.The results show that the physical properties of recycled coarse aggregates are significantly improved by pre-soaking lime water combined with carbonation,with 15.2%-22.9%reduction in water absorption and 15.2%-17.7%reduction in crushing index;the interfacial transition zone of recycled concrete is more compact after strengthening,which is beneficial to the quality of recycled coarse aggregates;the strengths at 7,28 d decrease with the increases of replacement rate;the strength of recycled concrete with coarse aggregates strengthened by pre-soaking in lime water and carbonation is comparable to that of ordenary concrete with 50%replacement rate.