Study and modeling of the compressive and splitting tensile strengths of polypropylene fiber reinforced concrete containing recycled asphalt pavement

In a context of sustainable development and material recycling, the present study aims to study mechanical properties of a recycled asphalt pavement (RAP) concrete, reinforced with polypropylene fibers (PF). First, five formulations were designed with different RAP content with a maximum of 50% at a water cement ratio (W/C) of 0,50. Experimental results showed that the more RAP content increases in mix, the more mechanical strengths decrease, mainly due to the weak interfacial transition zone (ITZ) between the mortar and the recycled material. Reinforcement of PF at 0.1% and 1% volume fraction was realized on all mixes and the experimental results showed that the compressive strength is increased while the splitting strength is decreased. Then, an experimental linear relationship between the splitting tensile strength and the compressive strength is proposed. In the second part of the study, the mechanical strengths were modeled using a factorial plan 22, giving a quantification of the individual effect of both introduction of the RAP and the reinforcement and the combined effect, on response in terms of compressive strength and splitting tensile strength. Established model predicted the mechanical strength of a hardened concrete, whatever the RAP content and whatever the PF reinforcement content.