Statistical Analysis on Grading Characteristics between Dense and Stone Matrix Asphalt Mixtures

Gradation information can be really useful when evaluating the performance of pavement, especially when the local climate condition or traffic volume have special requirements on gradations of asphalt pavement. However, due to poor management or long construction time, it may be difficult to accurately acquire the asphalt gradation type on site. To solve this problem, this study aimed to analyze the grading characteristics of both asphalt concrete (AC) and stone matrix asphalt (SMA) mixtures through statistics and to propose a quantitative indicator that could distinguish them rapidly. Methodologically, passing rate difference (PRD) between two adjacent sieve sizes was used to characterize the gradation and to distinguish AC from SMA. Five sieve sizes were considered in this study, namely, 16 mm, 13.2 mm, 9.5 mm, 4.75 mm, and 2.36 mm, and four PRDs were computed and analyzed. A total of 854 sets of gradation data were collected from 437 papers. To study the influence of nominal maximum particle size (NMPS), the data were further categorized into three types, namely, gradation data with NMPS of 16 mm, 13 mm, and regardless of NMPS. As a result, in all cases of NMPS, critical PRDs were determined to distinguish between SMA and AC mixtures. Moreover, when a critical PRD was determined, for a given gradation, the confidence level to correctly identify an AC gradation was generally higher regardless of NMPS.