再生骨料混凝土吸湿性能及对干燥收缩的影响  

Isothermal Sorption of Recycled Aggregate Concrete and Its Influence on Drying Shrinkage

作　　者：郭远臣[1] 王雪[1] 何运祥[1] 

机构地区：[1]重庆三峡学院土木工程学院,重庆404100

出　　处：《建筑材料学报》2012年第3期386-390,405,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50774039);万州区科委科技攻关项目(WZ011R003);重庆三峡学院校级重点项目(11ZD-14)

摘　　要：根据孔隙结构理论设计了测量材料润湿性能的装置,测试了再生骨料取代率,减水剂、膨胀剂、粉煤灰掺量对再生骨料混凝土吸湿量的影响曲线,并通过曲线拟合给出不同配合比再生骨料混凝土等温吸湿曲线函数关系式;提出可由初期吸湿曲线来计算材料与水接触角大小,并分析了其对再生骨料混凝土干缩性能的影响.研究表明:再生骨料、减水剂的添加可减小混凝土的接触角,增加混凝土的干缩值;粉煤灰的添加改善了混凝土孔隙结构,能降低与水润湿性,有利于抑制混凝土收缩;减水剂的添加减小了再生骨料混凝土的接触角;膨胀再生混凝土收缩机理不能单用材料润湿性和孔隙结构理论来解释.Based on pore structure theory, a device for measuring the wetting properties of materials was designed. The effect of recycled aggregate replacement rate, and water reducer, expansive agent, fly ash dosage on isothermal absorption of recycled aggregate concrete was investigated. Through curve fitting, the function relationship of isothermal absorption curve of recycled aggregate concrete with different mix proportion was established. It is proposed that the water contact angle can be calculated from the initial absorption curve, and its impact on drying shrinkage of recycled aggregate concrete is analyzed. Research results show that the addition of recycled aggregate and superplasticizer lowers the contact angle of recy- cled aggregate concrete, and increases the drying shrinkage. The addition of fly ash improves the pore structure of concrete, and can reduce the wettability, which can help inhibit the shrinkage of recycled ag-gregate concrete; It is difficult to explain the shrinkage mechanism of expanded recycled concrete only from material wettability and pore structure theory.

关 键 词：再生骨料混凝土(RAC) 吸湿量 润湿性 干燥收缩 

分 类 号：TU528.7[建筑科学—建筑技术科学]