Performance-based design for binary-blended filler application in dense-graded cold mix asphalt

Abstract

The quest to developing a universally acceptable mix design procedure for cold mix asphalt (CMA) is in the spotlight of continuous research. Moreover, the performance improvement of CMA coupled with sustainable construction drives had witnessed the inclusion of industrial by-products and biomass waste alike in CMA. Nonetheless, various transportation departments in different countries tailor CMA’s design to suit their geographic regions’ peculiar challenges. Despite such efforts, mix designs need to produce laboratory results replicative of service conditions capable of ameliorating the high void content, weak early strength, and slow rate of strength gain of CMAs. This study proposed a performance-based mix design based on the combined result of indirect tensile stiffness modulus (ITSM) and Cantabro loss tests compared to the standard Marshall mix design. The mixtures contain binary blending of 1–4% palm oil fuel ash (POFA) with 3–6% granite filler by total aggregate weight in a fine dense-graded CMA using a polymer-modified cationic quick set (CQS-1h) and an unmodified rapid set (RS-1K) emulsified asphalt. A gradation with a nominal maximum aggregate size (NMAS) of 4.75 mm (FGCMA-4.75 mm) was employed. In addition to Cantabro and ITSM, the designed mix was tested for Indirect Tensile Strength (ITS), and modified Lottman’s test. Results revealed a significant correlation between the usual Marshall design with the proposed design based on the established optimum emulsion contents (OEC). An optimal 3% POFA yielded moisture-resistant mixtures with enhanced mechanical and Marshall volumetric properties in void reduction, increased stability, and adequate early strength.