Study on Shrinkage and Crack Resistance of High-performance Concrete Reinforced by Fiber Internal Curing Lightweight Aggregate Composite Materials
To alleviate high shrinkage,easy cracking and other volume stability insufficiency problems of high performance concrete,based on the composite effect of fiber-inner curing materials,the self-shrinkage performance and anti-cracking performance of high performance concrete under the conditions of different lightweight aggregate-inner curing agent substitution rate(10%～20%)and fiber combinations(steel fibers,polypropylene fibers,and blended fibers)were analyzed by non-contact self-shrinkage meter and plate method.The results show that:1)The substitution rate of lightweight aggregate has a significant effect on reducing the early self-shrinkage,which can not only reduce the 3 d and 28 d self-shrinkage by 42.8%-62.6%and 14.5%-32.8%,respectively,but also can increase the growth rate of self-shrinkage in the late 28 d period;2)The combination of fibers and lightweight aggregates further reduces the maximum self-shrinkage rate of 28 d by 45.8%and reduces the self-shrinkage rate of 28 d by 60%(1.2%,1.2%).The growth rate can be reduced by 60%(1.2～1.44 μm/d)after 28 d;3)The incorporation of lightweight aggregates and fibers has a significant effect on the reduction of crack area,the number of cracks and the maximum crack width and length,and the three kinds of fibers have a significant effect on the reduction of crack area,in the following order:steel fibers<polypropylene fibers<mixed fibers and mixed fibers can further reduce the rate of the development of the crack area in the late stage;4)Under the combination of fiber and 20%lightweight aggregate substitution rate,the relative anti-cracking index is 94.7%-98.7%,and the maximum crack length and width can be reduced by 92.7%and 90%at the same time;5)The composite effect of fiber-inside curing materials can significantly improve the shrinkage and crack resistance of high-performance concrete,which can be promoted in engineering practice.
万方数据
维普
