Mechanical Characterization of Combi-layer

摘要

Combi-layer consists of a porous asphalt concrete layer with veryhigh voids content (25 percent), of which the voids are filled with cementslurry. In this paper research is reported into the mechanicalcharacterization of combi-layer. This was necessary because manyasphalt technologists see combi-layer as an intermediate between asphaltconcrete and cement concrete with some concrete-like properties at hightemperatures. No relevant material characterization was available fromliterature.The normal testing procedures for the mechanical characterization ofasphalt concrete mixtures have been executed. From the test resultsmaster curves for the stiffness over a large temperature area, indirecttensile strength and fatigue lines at design temperatures are reported.Because of the suggested difference with the standard asphaltconcrete mixes a fundamental characterization of the material wasdeemed necessary. Uni-axial tension and compression tests wereperformed at several temperatures and strain rates. In this papermonotonic tension and compression tests with a constant strain rate arereported.In the paper the uni-axial properties of the combi-layer material arecompared with asphalt concrete and cement concrete. From thecomparison it becomes clear that the combi-layer behaves similar to anasphalt mix. At high temperatures it cannot perform without confinementunder loading like cement concrete. This is best shown with thetemperature dependence of the material properties.