Study on flexural fatigue characteristics of hybrid fiber ECC-concrete composite pavement slab

A kind of hybrid fiber ECC(HE) with more outstanding ductility was proposed, which was poured on the ordinary concrete(PC) base as an overlay to form a composite road slab. The conventional ECC(CE) and PC overlays were selected as the control group. The results show that the overlay has little effect on the compressive strength of the composite pavement slab and could be ignored. When h=25 mm, the flexural fatigue resistance of HE composite pavement slab is significantly improved compared with PC pavement, and the improvement is better than CE at the same layer thickness, and the interlayer adhesion is also ideal. From a microscopic point of view, the adhesion between the fiber and the matrix is greatly strengthened because of the incorporation of EVA, fly ash and silica fume. PVA fibers, modified polypropylene (MPP) fibers and calcium carbonate whiskers(CW) are distributed in random directions in their respective sizes. During preventing cracks, they provide more nucleation sites for hydration products, accelerate precipitation, and make the structure more dense. The analysis of economic benefits shows that the cost of HE per cubic meter is only 1/4.65 of CE, and the amount of cement is greatly reduced. © 2021, Central South University Press. All right reserved.