Investigation of the use of strip-prone aggregates in hydraulic asphalt concrete

✍ Scribed by Weibiao Wang; Yingbo Zhang; Kaare Höeg; Yue Zhu

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 916 KB
• Volume: 24
• Category: Article
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2010.04.043

✦ Synopsis

A study is made of the suitability of strip-prone aggregates for use in asphalt concrete water barriers in embankment dams. Standard boiling tests were used for ranking various aggregate types with respect to water susceptibility and aggregate-bitumen adhesion. Indirect tension tests (splitting tests) were used to study the effects of aggregate-bitumen adhesion on asphalt concrete tensile strength. The test results show the significant detrimental effects of using strip-prone aggregates for open-grade porous asphalt (air void 4-10%), but that aggregate-bitumen adhesion and tensile strength could be increased by adding amine or hydrated lime to the asphalt mix. However, a similar test series on dense-grade hydraulic asphalt (air void 2-3%) shows no detrimental effects of using strip-prone aggregates. Furthermore, there were no significant differences in compressive strengths or beam bending strengths and strains at failure between specimens with or without strip-prone aggregates and with or without amine added. This was the case even for specimens having been cured by exposure to 100 freeze-thaw cycles at +25 °C to À25 °C. For hydraulic asphalt, which is virtually impervious with a significant bitumen film thickness covering the aggregate particles, it does not seem required to use additives to improve the aggregatebitumen adhesion properties. However, further testing should be done to study any long-term effects of using strip-prone aggregates.