Volumetric Analysis of Cold Asphalt Mixtures Compacted Using the Marshall Compactor and the Superpave Gyratory Compactor

Abstract

Understanding the behaviour of an asphalt mixture in terms of its volumetric properties is important since volumetric properties provide an indication of the performance of the asphalt mix when subjected to various conditions of traffic loading.

This paper discusses the volumetric properties of cold asphalt mixes prepared at the optimum residual bitumen content using selected aggregates and bitumen emulsion binder. The main focus was the density and voids content of laboratory specimen compacted using the Marshall compactor and the superpave gyratory compactor, at compactive efforts recommended for low to medium traffic loading. Density and void contents for Marshall compacted samples at a compactive effort of 50 blows on either side of the specimen were compared to achieved parameters at 75 superpave gyrations. For superpave gyratory compacted specimen, it was possible to estimate the density and voids content of the mix during the compaction process as the number of gyrations were increased.

The percent air voids content of the cold asphalt mix samples remained very high (>7%) for both methods of compaction. However, mixes that were densely graded had lower air void contents compared to those with less dense particle parking.