基于原生混凝土性质评价的再生骨料质量评价

Quality Appreciation of Recycled Aggregate Based on Property Evaluation of Original Concrete

通过测试不同原始配比、使用环境、结构部位、结构形式、服役年限的废弃混凝土的强度、吸水率、表观密度等便捷手段来获得混凝土基本特征,探索其与再生骨料和再生混凝土性能之间的普遍性关系。表观密度过低的混凝土强度低,表观密度超过2300kg/m3的混凝土所表现的强度都不低于20MPa,再生骨料的吸水率处于2%～6%。再生骨料吸水率随着原生混凝土强度的增加而降低。新拌混凝土坍落度随着骨料吸水率的增加而降低,采用预先淋水的办法,可初步解决骨料吸水率大的问题。废弃混凝土碳化与再生骨料的性质之间无明显关系。

Compressive strength, water absorption, apparent density of waste concrete which had differences in mix proportion, environments, structural part, structural style and age were tested. The general relationship between characters of recycled aggregate （RA） and recycled aggregate concrete and characters of waste concrete was established. Concrete with low apparent density has low strength, the strength of concrete with apparent density over 2300kg/m^3 is not less than 20MPa, and with water absorption is between 2%-6%. The water absorption reduced with the increasing of waste concrete, the slump of fresh concrete decreases if water absorption of aggregate increases, as can be solved imperfectly by pouring water. There were no obvious relation between carbonation of waste concrete and character of RA.