Abstract:

In order to reveal the effect of polypropylene fibers on the fracture toughness of cement-stabilized macadam, the three-point bending experiments of polypropylene fiber-reinforced cement-stabilized macadam and common cement-stabilized macadam were carried out. The fracture energy, the crack mouth opening displacement and the crack tip opening displacement of the specimens were also measured. Moreover, an appropriate volume fraction of polypropylene fibers was suggested, namely, 0.6‰ to 0.‰. Test results indicate that （ 1 ） the fracture energy, the ultimate crack mouth opening displacement and the ultimate crack tip opening displacement of cement-stabilized macadam obviously increase when the macadam is reinforced with polypropylene fibers, and gradually increase with the volume fraction of the fibers ; （2） with the prolonging of curing period, the fracture energy gradually increases with the curing period no matter whether polypropylene fibers are added in the macadam or not; and （3） with the increase of cement content, the ultimate load gradually increases while the fracture energy gradually decreases.

Key words: polypropylene fiber, cement-stabilized macadam, fracture energy, crack mouth, crack tip, opening displacement