Resilient Modulus Performance of Warm Mix Asphaltic Concrete using Cecabase RT Additive

Warm mix asphalt is an energy efficient mix that can be produced at lower temperature than the conventional hot mix asphalt, while maintaining the properties and performance required for the conventional hot mix asphalt. This paper presents a study in mix design of dense graded asphaltic concrete using a warm mix additive known as Cecabase RT. Type AC14 gradation for granite aggregates and bitumen of penetration type 60/70 were used for this study based on the Public Works Department of Malaysia’s Standard Specification for Road Works. The mixing temperature for the control sample AC14 mix without the additive was set at 160°C while for the mix using the Cecabase RT additive, the mixing temperature was set at 135°C. Marshall test procedure were then used to prepare the samples and volumetric properties were then evaluated to determine the optimum bitumen content. The optimum Cecabase RT additive content was then determined using samples prepared at the optimum bitumen content. The resilient modulus test was then carried out on the samples based on the repeated load indirect tensile test at temperatures of 25°C and 40°C at three different pulse repetition periods. From the analysis of the results, it was found that optimum bitumen content was at 4.9% while the optimum Cecabase RT additive content for the AC14 mix is 0.3%. The resilient modulus values obtained for the mix using Cecabase RT warm mix additive is higher than the control samples at both test temperatures and at all the pulse repetition period tested. It can be concluded that the use of Cecabase RT additive have the advantages of reducing the mixing temperature, thus producing a more energy efficient mix while improving the stiffness of the mix in terms of resilient modulus values, thus increasing a pavement load carrying capacity.