Digital image processing of warm mix asphalt enriched with nanocolemanite and nanoulexite minerals

Abstract

Digital image processing (DIP) is a method used to view the internal structure of hot mix asphalt. However, in this study, the DIP of warm mix asphalt (WMA), which reduces environmental emissions and saves energy, was been investigated. Firstly, colemanite and ulexite minerals, of which the global reserves are abundant, were ground in a ball mill and nano-sized particles were observed for the first time in TEM micrograph. Secondly, these minerals were added to the foamed WMA in varying amounts of micron/nano-size. Marshall stability and repeated creep tests were performed and the void ratios in the mixtures were analyzed. Thirdly, a DIP system was designed. The primary purpose of this method was to scrutinize the impacts of voids and bitumen ratios around aggregates and the adhesion effect between the bitumen and aggregate. Finally, the void ratios identified by these tests were utilized to compare with those specified by the DIP method. The best deformation resistance for the ulexite appeared to result in a 5 %U + 53 μ mixture, whereas the highest deformation resistance for the colemanite yielded in 5 %C − 25 μ and 10 %C − 25 μ mixtures, according to repeated creep test results. The samples' void ratios identified around the aggregates were the lowest (1.35%) in the 5 %U − 25 μ mixture and the highest (3.72%) in the 10 %U − 25 μ mixture. It was concluded that the designed DIP was quite good in the interpretation of WMA with nanocolemanite and nanoulexite additives.