Modified Micro-Deval Procedure for Evaluating the Polishing Tendency of Coarse Aggregates
| Autor: | Wenjing Xue, Linbing Wang, D. Lane, Cristian Druta |
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| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Transportation Research Record: Journal of the Transportation Research Board. 2232:34-43 |
| ISSN: | 2169-4052 0361-1981 |
| DOI: | 10.3141/2232-04 |
| Popis: | Coarse aggregates in asphalt concrete should be tough and durable to withstand hot-mix asphalt production, transportation, construction, traffic loads, and environmental effects. The morphology of such aggregates plays an important role in aggregates' mechanical properties and influences asphalt pavement skid resistance, an essential characteristic of pavement performance. The predominant aggregate resources in western Virginia are carbonate rocks. The mineral components tend to be relatively soft, and when subjected to abrasive wear under traffic, the aggregate surface polishes fairly rapidly. This situation leads to smoothing of the surface and creates potential safety issues due to loss of surface friction. Considering all aspects, the increasingly popular Micro-Deval (MD) apparatus was used to assess the abrasion–polishing (A-P) resistance of coarse aggregates suspected to show a range of polishing characteristics. Although the conventional focus of the MD test is on attrition or degradation (mass loss) reflecting particles' durability, such attrition or degradation also induces a polishing effect on susceptible particles and consequently was selected for this study. Hence, a suite of carbonate and noncarbonate coarse aggregates from 10 Virginia sources was tested in the MD with the standard procedure and a cyclical A-P procedure. Also, two-dimensional digital aggregate images, before and after abrasion, were obtained and analyzed with the use of specialized software to characterize morphological parameters (shape, angularity, texture). Testing results showed that wear-resistance aggregate groupings based on the A-P procedures were consistent with the polishing tendency based on lithologic characteristics. Abrasion effects induced by both MD procedures were subjectively discernable. Trends could be perceived in the image analysis data, but the differences were not statistically verified. |
| Databáze: | OpenAIRE |
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