Designing Stone-Matrix Asphalt to Optimize Sustainability Using Limestone, Dolomite, and Crushed Gravel Aggregates

Stone-matrix asphalt (SMA) relies on stone-on-stone contact of coarse aggregate (CA) to generate a load carrying structure or an aggregate skeleton that minimizes flexible pavement rutting potential. Local CA may require relatively shorter distance hauling thereby making SMA more sustainable and cost-efficient but may have lesser quality characteristics than igneous aggregate. Hence, possible aggregate breakage must be quantified and addressed in the mix design. In this paper, SMA was designed using limestone, dolomite, and crushed gravel aggregates, which may result in relatively greater aggregate breakage. Fourteen SMAs were designed using different CA sources with various qualities. A methodology was proposed to measure aggregate breakage during compaction and rut testing of SMA by recovering the aggregates through extraction. An index was introduced and calibrated to quantify aggregate breakage. This allows assessing aggregate structure integrity during SMA production and paving.