Impacts of Aggregate Gradation Characteristics on Mix Design Parameters for Cold Mix Asphalt: Analytical Estimation Using Predictive Models
Abstract
This study evaluated characteristics of aggregate gradations and assessed its impacts on mix design parameters of cold mix asphalt (CMA). At first, a gradation envelope of a total of eight aggregate gradations was chosen in this study based on an extensive literature review. Next, the aggregate gradations were analyzed using continuous maximum density plot, Bailey method, and fractal dimensions to assess aggregate size distribution and packing characteristics. After that, three gradations were selected from the gradation envelope, and mix design was carried out to determine the key mix design parameters in the laboratory. To examine the impact of the gradations characteristics on mix design parameters, correlation analysis was conducted for CMA. The study findings revealed that coarse aggregate (CA) ratio and coarse portion of fine aggregate (FAC) ratios of aggregate gradation exhibited a strong correlation with mix constituents, volumetrics, and strength of CMA. Furthermore, predictive models were also developed to estimate the mix design parameters as a function of CA and FAC ratios, exclusively. These models can also be used to predict the trial mix constituents and design the aggregate gradation as per requirements. It is envisaged that the study findings would help the researchers, engineers, and practitioners to gain important insights into the design aggregate gradations for CMA and thus advancing the state-of-the-art pertaining to the design and development of CMA.