Influence of ternary blended cementitious fillers in a cold mix asphalt mixture

Abstract

The manufacture of conventional hot mix asphalt (HMA) for paving has a substantial environmental footprint, and the production of clean asphalt mixture with good engineering performance is critically important. The introduction of cementitious filler is a promising approach to achieve outstanding mechanical properties for cold mix asphalt (CMA) as a clean paving material. This study aims to develop a novel CMA formulation through the combination of ordinary Portland cement (OPC) with two industrial by-products: fly ash (FA) and ground-granulated blast furnace slag (GGBS), which could make CMA even cleaner. To achieve this objective, the effects of ternary blended cementitious fillers on the early-age strength, engineering performance, and microstructural properties of CMA are characterized through comprehensive laboratory tests. The experimental results indicated that the indirect tensile strength of CMA-B containing 2% OPC, 1% FA, and 1% GGBS is approximately 20% higher than that of the mixture with 2% OPC (CMA-2% OPC). The residual Marshall stability ratio of CMA-B was increased to about 95% and its dynamic stability was approximately 10 times that of CMA-2% OPC. Employing blended cementitious fillers in CMA facilitates the formation of hydration products with excellent stiffness, reduces the air voids, and enhances interface bonding between aggregate and asphalt matrix, and thus suitable for applications in road pavements subjected to harsh service conditions in terms of moisture and temperature.