Experimental and analytical investigation of metakaolin and polypropylene fiber addition on some properties of roller compacted concrete pavement

In this study, mechanical properties of roller compacted concrete pavement (RCCP) containing metakaolin (MK) with or without polypropylene fibers (PP) are experimentally and analytically investigated. For this purpose, sixteen different mixes were designed and tested in the lab. The effect of using polypropylene fibers in 0, 0.05, 0.1 and 0.2 percent of cement volume with metakaolin powder in 0, 7.5, 15 and 22.5 percent of cement weight was investigated. Compressive strength, tensile strength and water absorption were evaluated. The results showed that the highest compressive strength occurs in the combination of 0.1% of PP and 15% of MK that increases the compressive strength of 7 and 28 days respectively, by 51% and 25% compared to the reference sample. The tensile strength using the above combination increased 42%, which is the highest increase in the tensile strength. With using of 0.1% of PP and 22.5% of MK, maximum decrease in water absorption was observed by 11% compared to the reference sample. In this research, analytical formulas predicted properties of the RCCP and estimated optimal combination of the PP and MK.