Effect of Saline Water on the Performance of Road Base Layer with Reclaimed Asphalt Pavement and Recycled Concrete Aggregate

Abstract

Road construction requires large amounts of natural aggregates while generating considerable waste materials such as reclaimed asphalt pavement (RAP) and recycled concrete aggregate (RCA). This study investigated the potential of using RAP, RCA, and a RAP-RCA mixture as alternatives to natural aggregates in base layers exposed to saline conditions. Local aggregates were prepared according to SNI standards. RAP was obtained from a local road construction contractor, and RCA came from concrete waste produced during laboratory testing. The Proctor and CBR tests (SNI 1743:2008 and SNI 1744:2012) were carried out using artificial seawater containing 3.5% NaCl for immersion periods of 4, 14, 28, and 56 days. Results showed that exposure to saline water reduced CBR values, particularly for RAP, due to weakened particle bonding. RCA retained better strength, while the RAP–RCA mixture showed moderate performance, satisfying Class B base course requirements for short-term use in coastal areas.