Investigating the Viability of Reclaimed Asphalt Pavement as Backfill Material for Sustainable Material Management

Abstract

This study examines the feasibility of using Reclaimed Asphalt Pavement (RAP) as a replacement for embankment and backfill materials in roads in Saudi Arabia. The research addresses the demand for sustainable material-management practices and reduced reliance on virgin materials with the increasing generation of construction and demolition waste. An experimental method was followed using RAP and natural fine aggregate from a construction site in the Tabuk region. The RAP was crushed, screened, and mixed with various proportions of natural material before laboratory evaluation. The experimental programme involved particle-size distribution using sieve analysis, Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) using the Modified Proctor compaction test, and the California Bearing Ratio (CBR) test. The results showed differences in the gradation, compaction, and bearing properties of the tested materials. The OMC values ranged from 7.1% to 7.3%, while MDD ranged from 2.080 to 2.240 g/cm³. CBR values at 100% MDD ranged from 34% to 83%. Among the five samples, Sample D showed the best performance, with an OMC of 7.1%, MDD of 2.240 g/cm³, and CBR of 83%. The results indicate that appropriately processed RAP has potential for use in embankment and backfill applications, subject to field validation and project-specific requirements in future.