Studying hydraulic conductivity of asphalt concrete using a database

A new database called AC/k-1624 containing over 1600 measurements of saturated hydraulic conductivity of asphalt concrete has been assembled and analysed. AC/k-1624 was used to investigate the effect of the grading entropy parameters on saturated hydraulic conductivity. A new prediction model comprising both air voids and grading entropy is presented. The database analysis using different predictors of asphalt hydraulic conductivity reveals that the gradation does affect the hydraulic conductivity, but the air void level is necessary to make reasonable a-priori assessments of hydraulic conductivity for asphalt concrete. The new empirical model is shown to have a good predictive capacity for hydraulic conductivity fitting more securely at higher values with more scatter observed at lower values. The effects of test type, gradation classification and Nominal Maximum Aggregate Size (NMAS) are also studied, revealing in general relatively modest influences on the computed regression coefficients.