Impact of aggregate and filler type on cold asphalt mixture attitude

Abstract

Cold asphalt mixture is generally a mix made of emulsified asphalt with aggregate. One kind of these mixtures is cold asphalt emulsion mixtures (CAEMs). Cold mixes have more economic and environmental advantages than hot mixes . This is the principal motivation for the present research, which aims to investigate the possibility of adopting these mixtures to be used as binder and/or surface course mixes in hot climatic areas, such as middle and south of Iraq. Also, this research will assess the mechanical properties of (CAEMs) incorporating more than one aggregate category and evaluates the possibility of designing (CAEMs) using recycled concrete aggregates and by-product mineral filler materials. However, the quality and gradation of the aggregate will have the greatest impact on the overall mechanical properties of the cold-mix asphalt since it is 95% of the mixture. Eight asphalt mixes were tested to examine the effects of variation in the aggregate gradation and type on mix properties using six types of materials namely (recycled concrete aggregate(RCA), natural aggregate, crushed sandstone, natural sand, limestone mineral filler, and cement kiln dust (CKD)). The guidelines contained in this research are intended to help mix designers with the decision of which materials to use and what are their percentages. The job mix formula (JMF) gradation was determined for each mix and the tested properties of emulsified asphalt mixture were Marshall stability, Marshall flow, split tensile strength and moisture damage effect at different curing period (i.e. 3,7, and 14 days ) at ambient testing temperature. The results specify that the emulsified asphalt type cationic slow setting (Css) is appropriate with considered materials. Finally, it can be conducted that the emulsified bitumen mixture contained recycled concrete aggregate and limestone filler material is a suitable alternative mixture to the cold asphalt mixture for binder and surface courses road construction in Iraq.