The effect of water-to-cement ratio on the fracture behaviors and ductility of Roller Compacted Concrete Pavement (RCCP)

•Fracture properties of RCCP were obtained using three different methods.•Results showed with decrease of WC ratio the fracture energy increases.•Results showed with decrease of WC ratio the fracture toughness increases.•Results showed RCCP ductility increases with increase of WC ratio. Roller compacted concrete (RCC) is a zero-slump concrete that has been extensively used in road pavements. This concrete has been considered, due to its economic and environmental potentials, including reduced construction and maintenance costs and greater environmental compatibility. A unique feature of the Roller Compacted Concrete Pavement (RCCP) is its low water-to-concrete (WC) ratio. Hence, RCCP is sensitive to the water content, compared to conventional concrete. This paper conducts an experimental studies on the effect of different ratios of WC on the fracture parameters of RCCP. For this purpose, three-point bending tests were performed on 162 notched beams and mechanical properties tests (compressive strength (fc), tensile strength (ft) and modulus of elasticity (E)) were performed on 54 specimens with different WC ratios (0.3to0.55). For all mixtures, the fracture parameters were determined using three methods: work of fracture method (WFM), size effect method (SEM), and boundary effect method (BEM). The results indicate a significant effect of WC ratio on RCCP fracture parameters, specifically, by decreasing w/c ratio from 0.55to0.3 it was observed that; (A) The initial fracture energy (Gf) and the total fracture energy (GF) increase in all three methods as a power function on fc; (B) The fracture toughness (KIC) increases linearly in SEM and BEM methods; (C) The characteristic length (Lch) in WFM, the effective length of the fracture process zone (Cf) in SEM, and the reference crack length (ductility index) (a∞∗) in BEM are decreased. The results also show that there is a relationship between GF measured by WFM method, and the Gf measured by SEM and BEM methods (GF≅2.43Gf(SEM), GF≅2.61Gf(BEM)).