Abstract:
A study done on the correlation of the Bailey method and the Dominant Aggregate Size Range (DASR) method managed to describe and develop new Bailey ratios that better describe the aggregate skeleton packing efficiency. DASR porosity was found to be linked to permeability as well. The aggregate skeleton is ‘deconstructed’ at macro, midi and micro level aggregate subset skeletons to evaluate the contributions of various aggregate fraction ranges. Bailey ratios were brought in line with the concept of nominator and denominator aggregate fractions that suit the DASR concept of contiguous fraction ranges and were described as the rational Bailey ratios. A data set which was based on Bailey method mix design was reworked to include the DASR porosities and the new correlated and rational Bailey ratios. This enabled the Bailey ratios and the DASR porosities to be related to rutting measured with Hamburg Wheel Tracking (HWT) tests. Other structural design parameters such as the Indirect Tensile Strength (ITS), Effective Film Thickness (EFT) of the binder mastic of these mixes were also correlated with various Bailey ratios and DASR fraction porosity ranges. The main purpose of this study was to confirm the viability of these new rational and correlated Bailey ratios and DASR porosities with rutting potential for further future detailed modelling via stepwise multiple regression analyses or via Neural Network Analysis (NNA) and modelling.
Description:
Papers presented at the 36th Southern African Transport Conference, CSIR International Convention Centre, Pretoria, South Africa on 10-13 July 2017.
