FATIGUE LIFE AND SUSTAINABILITY OF POLYPROPYLENE FIBER-REINFORCED CONCRETE FOR CONCRETE PAVEMENT

Abstract

This paper presents the fatigue properties of polypropylene fiber-reinforced concrete (PPFRC) in flexure at various stress ratios and the sustainability of PPFRC in terms of environmental impact and material cost for jointed concrete pavements. In this study, prism specimens with a size of 100 × 100 × 400 mm were cut from slabs with a size of 1000 × 1000 × 100 mm, considering the effects of fiber distribution and orientation. A polypropylene fiber with a size of 0.7 × 30 mm was mixed into concrete at 1.0 and 1.3 vol.%. Fatigue tests were conducted under four-point flexural loading to obtain the S-N curve for each mixture. In this study, plain concrete (PLC20) with a maximum aggregate size of 20 mm was also used, and its fatigue strength was compared with that of the PPFRCs. Based on the fatigue test results, the S-N curves called the Whöler curve were proposed. The fatigue life of the 1.3 vol.% PPFRC was longer than that of PLC20 at a lower stress ratio. Using the obtained S-N curves, a jointed concrete pavement was designed. The fatigue life of the thinner PPFRC with 1.3 vol.% pavement was enhanced significantly compared with a normal jointed concrete pavement. Consequently, despite the higher initial material cost, the 1.3 vol.% PPFRC can reduce pavement thickness and CO₂ emissions.