Analyzing the durability of adhesion stability of asphalt mixtures

Tereza Valentová, Jan Valentin

Last modified: 2019-03-04

Abstract


Adhesion is one of the fundamental characteristics related to asphalt mixtures. It determines significantly the durability of asphalt mixture and depends not only on the quality of aggregate particles coating but also on the hydrophobity or hydrophility of the aggregates. For this reason often mineral-based or chemical additives are used to improve adhesion between bitumen and aggregate particles. Mainly with the latter group of additives long-term stability is connected. Amine based additives are often used which unfortunately contains easily volatile compounds. If part of the effective substance is evaporated during mixing and paving the later durability can be negatively influences. Therefore it is important not only to assess the adhesion when virgin bitumen and aggregates are used, but also the artificially aged binders or asphalt mixtures have to be evaluated. For this reason long-term research is in progress at the Czech Technical University in Prague focusing on different aggregates (different mineralogy) and different adhesion promoters. Tests are run on virgin materials as well as on specimens long-termly aged (either bitumen by RTFOT+PAV or 3xRTFOT/TFOT, or asphalt mixtures which are usually aged for 5 days at 85°C). For bitumen-aggregate adhesion determination a standardized procedure according to CSN 736161 is performed. For asphalt mixtures the water susceptibility test according to EN 12697-12 is done on Marshall test specimens compacted by 2x25 blows. The paper presents some of the findings, including the impact of long-term ageing effects

Keywords


adhesion stability, adhesion promoter, water susceptibility, asphalt mixture

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