Comparative study on the effect of synthetic fiber on the preparation and durability of airport pavement concrete

In order to improve the durability of airport pavement concrete, four kinds of synthetic fiber reinforced concrete were researched in this paper. Modified polyester synthetic fiber concrete (MPFC), Monofilament polypropylene synthetic fiber reinforced concrete (MPSFC), Reticular polypropylene synthetic fiber reinforced concrete (RPFC), and Polyacrylonitrile synthetic fiber reinforced concrete (PSFC) were prepared in this paper. Strength, impermeability and frost resistance of them were investigated. The impermeability test was carried out by hydrostatic pressure and chloride ion penetration method, while the frost resistance test was conducted by quick freezing method. The results show that the synthetic fiber improves concrete flexural strength, but it has little effect on compressive strength. Under the same volume fraction (0.1%), the flexural strength of MPFC and PSFC increased by about 6% compared with that of ordinary concrete (PC), but the flexural strength of PSFC increased slightly, with only 1-2%. Single fiber can improve concrete impermeability and frost resistance. Among them PSFC impermeability is the best, which is 2.4 times of that of PC, up to P24; the frost resistance of MPFC is the best, which is 2 times of that of PC, reaching F350. Polycarboxylic synthetic water-reducer (SDJ) can improve concrete impermeability and frost resistance greatly. It has best impermeability when mixing with polyacrylonitrile fiber, and its frost resistance grades were all up to above F600 when mixing with the four kinds of fibers separately. It is suggested that the optimum volume fraction is 0.10-0.14%, as the fiber content also has certain influence on the performance of the synthetic fiber concrete. At last, the Cost-benefit analysis of the fiber reinforced concrete was put forward, which showed that the application of fiber concrete in the airport pavement engineering has great economic benefits and broad prospects for development.