Comparison of foamed asphalt and Portland cement stabilized on recycling pavement materials

Abstract

Foamed asphalt mixing is an innovated process that utilizes the benefits of foamed asphalt cement. Foaming occurs when small amounts of water are added to hot asphalt, thereby increasing the surface area and significantly reducing the viscosity of the asphalt. In this form it is suited for mixing with cold damp aggregates. This research investigated the feasibility and the suitability of foamed asphalt to stabilize reclaimed asphalt pavement (RAP) or recycled material obtained from Phisanoulok-Uttradit project. The RAP was mixed with virgin aggregates at proportions of 100:00, 50:50 and 0:100. The selected foamed asphalt binder was found to be 2.35%, 2.50% and 2.90% for 100%, 50% and 0%RAP mixtures respectively. The laboratory tests of three foamed asphalt mixtures revealed that in all cases, the 100%RAP mixtures had the poorest properties, while the 0%RAP mixtures generally had slightly better properties than 50%RAP mixtures. The Portland cement mixture used 100% reclaimed asphalt pavement aggregate per cement content at the proportion (RAP: Cement) of 100:2, 100:3, 100:4 and 100:5. The laboratory tests of the Portland cement stabilized mixtures showed that the higher cement contents result in higher indirect tensile strength, resilient moduli, and