Effects of Polyethylene Terephthalate and Crumb Rubber on Selected Properties of Asphaltic Concrete

Abstract

This study investigated the combined effects of polyethylene terephthalate (PET) and crumb rubber (CR) as modifiers on some properties of asphaltic concrete. Asphaltic concrete materials were obtained from a construction site. CR of 9.5 mm size was obtained by sieving, while PET bottles were collected, sorted, washed, dried and shredded by mechanical means. The physical properties of these materials were determined following standard procedure. Bitumen was modified by wet process with PET and characterised. Asphaltic concrete samples with partial replacement of coarse aggregate in the mix with CR were prepared. Samples without modifiers were also prepared as control. These were subjected to Marshall Stability test. The percentage variation for stability and flow between the control and the modified mixes, were 27 % and 0.29 % respectively, while those of the volumetric properties of bulk density, voids filled bitumen (VFB), air voids (VA) and voids in mineral aggregate (VMA) were 0 %, - 0.13 %, 0 % and 0 % respectively. It was concluded that, there was no difference between the flow and volumetric properties of the control and modified mixes.

Keywords

• polyethylene terephthalate
• crumb rubber
• asphaltic concrete
• stability, flow
• volumetric parameters