Selection of Laboratory Aging Procedures for Asphalt-Aggregate Mixtures

摘要

The report presents the results of a preliminary investigation to evaluate aging methods for asphalt-aggregate mixtures. Short-term methods included oven aging and extended mixing, while long-term methods included oven aging and oxygen enrichment. The effects of temperature and aging duration are presented. Test specimens were fabricated from two asphalts and two aggregates, representing extreme property levels. The four mixture combinations were prepared at two levels of permeability representing good and moderate compaction conditions. The effects of aging were determined using the diametral resilient modulus test. Following this preliminary investigation, oven aging of loose mixture for 4 h at 135 C (275 F) is recommended as a short-term aging procedure for future use. For long-term aging, both oven aging and low-pressure oxidation are recommended for future use. For dense mixtures using stiff binders, oven aging for 5 days at 85 C (185 F) is recommended. For open-graded mixtures, or those with soft binders, low-pressure oxidation for 5 days at 85 C (185 F) is recommended. The procedure is more difficult to carry out than oven aging but has the benefit that it supports the specimens during the aging procedure. (Copyright (c) 1994 National Academy of Sciences.)