Development of Equipment and Protocols to Test Laboratory or Field Applied Chip Seals on Compacted Asphalt Concrete

Abstract

This paper's primary objective was to present developmental efforts and experimental data for the Chip Seal Abrasion Test (CSAT). The CSAT focuses on aggregate retention by testing a chip seal placed onto compacted asphalt concrete by applying abrasive forces through a rubber hose. Time to 100% mass loss is the primary test output. Review of literature provides evidence that a protocol with all the CSAT’s features is largely non-existent. Work was divided into four components: 1) develop laboratory equipment and protocols to place a chip seal onto asphalt concrete; 2) develop laboratory equipment and protocols to evaluate aggregate loss of chip seals placed onto asphalt concrete; 3) monitor chip sealed pavements and collect cores for testing; 4) compare laboratory produced and field applied chip seals when using the same materials. Component 3 evaluated two Mississippi chip seal projects; one used Size 7 limestone and the other used Size 89 limestone. Replication of field behavior with laboratory produced specimens was only successful for Size 7 aggregates after very short durations in service. Laboratory applied Size 7 chip seals, on average, had 97% of the time to 100% mass loss in the CSAT test as did field applied chip seals. Laboratory applied Size 89 aggregates did not represent field applied chip seals taken after very short durations in service. Laboratory applied Size 89 chip seals, on average, had 46% of the time to 100% mass loss in the CSAT test as did field applied chip seals.