M. Naqiuddin M. Warid

Effect of Aging on Resilient Modulus of Hot Mix Asphalt Mixtures

Asphalt hardens as a result of an aging process. This study was undertaken to determine the effect of field aging simulated by laboratory aging method of different hot mix asphalt (HMA) mixture. Three types HMA mixtures were used for this study namely Asphaltic Concrete with 10 mm nominal maximum aggregate size (AC 10), Aspaltic Concrete 28 mm (AC 28) and Porous Asphalt 10 mm (PA 10). The resilient modulus test was carried out as an indicator of the performance at a 25 °C and 40 °C. Generally, all samples show similar trend which aged mixture produced slightly higher resilient modulus compared to unaged mixture while an increase in temperature from 25 °C to 40 °C might reduced the resilient modulus up to 88%. This study also found that the difference increment of resilient modulus after the aging process attributed by asphalt content, air void and gradation of respective mixtures.

Investigations of rubber dipping by-product on bitumen properties

Nowadays, there are a lot of damaged of road pavement and it become a very serious issue in Malaysia. To minimise the damage of pavement surface and increase durability of flexible pavement, the conventional bitumen needs to be improved with regards to performance related properties. Thus, this study is to investigate the effect of rubber dipping by-product (RDP) on bitumen properties. In order to achieve this aim, the objectives of this study are; i) to determine of non-modified bitumen and the effect of added RDP in different concentration on bitumen properties; and ii) to compare non-modified bitumen and RDP modified bitumen in terms of physical properties. RDP is waste material from natural rubber industrial and it is in solid forms. Bitumen grade 80/100 PEN was used in this study. Laboratory tests were penetration, softening point, viscosity, rolling thin film oven (RTFO) and pressure aging vessel (PAV) tests. The findings show that addition of RDP causes the modified bitumen harder than before, indicate higher temperature susceptibility and increased viscosity properties. From the study stated that the suggested proportion of RDP to be mixed with bitumen is 10 percent by total weight.