混杂纤维对大掺量矿物掺合料混凝土干燥收缩的影响

Effect of Hybrid Fibers on Drying Shrinkage of Concretes with High Content Mineral Admixtures

通过测定混凝土的长期干燥收缩值,研究了单掺聚丙烯(polypropylene,PP)纤维、聚酯纤维和钢纤维及其混杂技巧对大掺量矿物掺合料混凝土干燥收缩的影响。结果表明,大掺量矿物掺合料混凝土的干燥收缩比较大,纤维及混杂技巧有利于降低其干燥收缩,纤维的弹性模量越高,其抑制干燥收缩的效果越好;(0.05%PP纤维+0.05%聚酯纤维)的有机纤维混杂效果优于(0.1%PP纤维+0.7%钢纤维)和(0.1%聚酯纤维+0.7%钢纤维)的有机与无机纤维混杂;混杂纤维对混凝土干燥收缩的抑制效果与纤维之间的搭配有关。综合分析表明,(PP纤维+聚酯纤维)的二元混杂技术具有良好的工程应用价值。

Long-time drying shrinkage of concretes was tested and the effects of polypropylene fiber, polyester fiber and steel fiber as well as their combination were investigated. Results show that concretes with high content mineral admixtures exhibit large drying shrinkage. However the fiber and hybrid fibers can effectively reduce the value. And the effect of drying shrinkage resistance will get better with the increasing module of the fiber. After combinations of three kinds of fibers were compared, combination of polypropylene fiber and polyester fiber yields the most obvious effect; the drying shrinkage resistance of hybrid fibers was related to fibers＇ collocation. The comprehensive analysis is that concrete containecl certain content of polypropylene fiber and polyester fiber shows good potential in engineering.