Using of Lime-Treated Recycled Concrete Aggregates (RCA) in the Design of Hot Mix Asphalt HMA

Abstract

The use of recycled concrete aggregates (RCA) in hot asphalt mixtures is one of the modern applications for these aggregates. Researches have shown that treating these aggregates with different techniques can significantly improve the performance of asphalt mixtures because it effects on the attached mortar layer, which is the main reason for decreased quality of the aggregates.

 This research aims to study the performance of hot asphalt mixtures designed from recycled concrete aggregates (RCA) treated with 3% quick lime, with replacement ratios 0-25-50-75-100% of the nature coarse aggregate by untreated and treated RCAs .

The results of the research indicated that lime helped to improve the physical and mechanical properties of the recycled aggregates up to 50% , Marshall density of the mixtures was improved by 3% , also  stability increased by 6-26% , while the optimum bitumen content required for the mixtures decreased up to 9% , which greatly enhances the possibility of using these aggregates in asphalt paving works.