减缩措施对陶粒混凝土干燥收缩及宏观性能的影响

Effect of shrinkage reduction measures on drying shrinkage and macro-properties of ceramsite concrete

研究了减缩剂、不同长度聚丙烯纤维和透水模板布3种减缩措施及其复合使用对陶粒混凝土干燥收缩和宏观性能的影响。结果表明:当单独采取减缩措施时,透水模板布的减缩率最大,达37.1%;其次是高掺量的减缩剂,其减缩率为34.0%;长度短的聚丙烯纤维减缩率仅为7.2%。当复合采取减缩措施时,减缩率都有提高,且减缩剂与透水模板布复合使用的减缩率最高,达46.8%。除单独使用聚丙烯纤维外,无论是单独还是复合采取减缩措施,都能提高陶粒混凝土的内部相对湿度。各减缩措施均能降低陶粒混凝土的孔隙率,细化孔径,且对陶粒混凝土的工作与力学性能无负面影响。

The effects of shrinkage reduction agent(SRA),polypropylene fiber(FF)of different lengths and controlled permeable formwork liner(CPFL)on drying shrinkage and macro-properties of ceramsite concrete were studied.The obtained results show that when the shrinkage reduction measures were used alone,the shrinkage reduction rate of permeable formwork liner was the highest(37.1%),followed by the shrinkage reduction agent with high content,whose shrinkage reduction rate was 34.0%.And the shrinkage reduction rate of polypropylene fiber with short length was the lowest(only 7.2%).When the shrinkage reduction measures were used together,the shrinkage reduction efficiency was higher.And the shrinkage reduction agent combined with the permeable formwork liner had the highest reduction rate of 46.8%.All the shrinkage reduction measures could improve the internal relative humidity of ceramsite concrete except the usage of polypropylene fiber.All the reduction measures could reduce the porosity of ceramsite concrete and refine the pore size.They also had no negative effect on the workability and mechanical properties of ceramsite concrete.