State of Knowledge for Cantabro Testing of Dense Graded Asphalt

Abstract

This paper uses information collected over several years to determine where the Cantabro test usefully characterizes dense graded asphalt (DGA). The Cantabro mass loss (CML) procedure is simple, expedient, and has been used for open graded materials for years. A database of approximately 1,200 measurements was analyzed alongside information from the literature to assess the usefulness of the CML procedure for DGA because this is not nearly as common as for open graded materials. Findings showed that several of the factors leading to durable mixes have been cited in the literature for some time but that a mix test to routinely assess all factors simultaneously has not found its way into routine practice. A mix test of this nature is needed now more than ever given that one of the main challenges is to produce mixes better balanced between rutting and cracking. Analysis showed that the Cantabro test detected the following items known to affect performance: binder grade, presence of polymer, difference between ground tire rubber and SBS modification, aggregate type, reclaimed asphalt pavement (RAP) content, density (air voids), volume of effective binder, and aging.