The bending fatigue performance of cement-stabilized aggregate reinforced with polypropylene filament fiber

Cement-stabilized aggregate reinforced with polypropylene filament fiber (CAPFF) is a new material for road base course of semi-rigid pavements whose bending fatigue performance has been rarely studied. The paper studied the bending fatigue performances of CAPFF (including two types of CAPFF, i.e., cement-stabilized macadam and gravel respectively reinforced with polypropylene filament fiber) with low mixing content, and then established their bending fatigue equations. Results show that, when under the same stress level, the fatigue life of CAPFF is improved by 1.0-4.2 times comparing with that of ordinary cement-stabilized aggregate. Meanwhile, the analysis of the fatigue equations indicates that, when using fibers, the bending fatigue strength of mixtures is appreciably improved, respectively about 30% in case of CMPFF and about 20% for CGPFF. When the stress level is under 0.75, the enhancement of fiber to cement-stabilized macadam is better than to cement-stabilized gravel; when the stress level is higher than 0.75, a reverse conclusion can be obtained. Ultimately, by the results from microtopography analysis by scanning electron microscope (SEM), the enhancement of the polypropylene filament fiber to the bending fatigue resistance of the cement-stabilized aggregates is analyzed.