Development of an Innovative Pavement Recycling Technique Using Fine RAP in Sand Concrete for Road Slabs

Abstract

The reuse of reclaimed asphalt pavement (RAP), sourced from the milling of existing pavements, offers an eco-friendly alternative to natural aggregates. It offers significant environmental benefits by reducing landfill waste and limiting the exploitation of natural resources. This study investigates the potential incorporation of fine RAP (FRAP) in the production of sand concrete, a particular type of concrete composed solely of fine aggregates. Firstly, five sand concrete mixtures were designed by partially or fully replacing natural sand with FRAP and were then assessed in terms of their mechanical characteristics and durability-related indicators. The results revealed that FRAP can be successfully used to produce sustainable sand concrete at replacement levels up to 50%, meeting all the mechanical performance requirements for pavement applications. The incorporation of FRAP also resulted in increased water absorption by immersion and higher sorptivity values. Yet, these values remained within the permissible limits for mixtures with 50% or less FRAP. Furthermore, given the critical role of elastic modulus in rigid pavement design, three predictive models were evaluated to estimate the elastic modulus of FRAP mixtures. The findings indicated that, when incorporating a correction factor reflecting aggregate quality, the ACI 318 model provided the highest accuracy, achieving a root mean square error of 1.5 GPa. The study confirmed the feasibility of reusing RAP in sand concrete, offering practical guidance for engineers to adopt this technique in pavement applications and encouraging greener construction practices.