Test Methods for Evaluation of Cold-Applied Bituminous Patching Mixtures

A Texas Department of Transportation study performed by the Texas Transportation Institute was undertaken with a goal of providing methods to assure the quality of cold-applied, asphalt-stabilized maintenance mixtures. Test procedures and acceptance criteria were developed for hot-mix, cold-laid asphalt concrete patching mixtures. Two specific objectives were to develop a test procedure to simulate approximately six months of stockpile-aging and a test procedure to quantify workability of maintenance mixtures. The protocol developed is designed to estimate the relative ability of a maintenance mixture to retain adequate workability after outdoor stockpile storage. This protocol could be useful as part of a specification to promote quality. Two test procedures were evaluated regarding their potential to quantify the workability of maintenance mixtures: a triaxial test and an unconfined compression test. Test results indicated that both procedures provide a relatively good measure of workability before and after aging. Two laboratory aging procedures were evaluated for their ability to predict workability of a stockpiled maintenance mixture after six months of field aging. Procedure A appeared to provide a reasonable approximation of six months of field aging.