Influence of Reactive Fillers on Evolution of Volumetric and Strength of Cold Mix Asphalt: Study on Moisture Loss Behavior

Abstract

The objective of this study was to evaluate the moisture loss (ML) behavior of cold mix asphalt (CMA) and establish its relationship with strength and volumetric with various types of fillers. This experimental program included four types of CMA mixes with different types and compositions of fillers at curing at two temperatures, 25°C and 38°C, and three durations: 1, 7, and 14 d. At first, the microscopic and mineralogical properties of five fillers were determined in order to understand their potential impact on CMA. Then, the ML behavior of the CMA mixes was analyzed for 14 d. CMA mixes exhibited distinct ML patterns based on the filler type used. Next, the volumetric properties of CMA were estimated, which featured transient behavior as the curing progressed. Air void (AV) increased over time as moisture evaporated, approaching total void (TV). The combined analysis of AV–TV distribution and incremental AV change effectively captured the evolving internal structure of CMA. Subsequently, the indirect tensile strength (ITS) of all mixes was evaluated at various curing stages for four CMA mixes. The ITS increased with curing, especially in the mix with fillers: cement and stone dust. Furthermore, a predictive model was developed to estimate the ITS, with R2 = 0.895, demonstrating a strong correlation across curing conditions. Though the incorporation of filler helps attain higher strength, it was not demonstrated through the ML and intrinsic mineralogical compositions of fillers. The present study bridged this gap, thereby advancing the state-of-the-art in the design and construction of CMA.