An investigation was carried out to evaluate the effects of post-consumerrecycled asphalt shingles (RAS) on various mechanical properties of a loess soil. Compaction, unconfined compression, split-cylinder indirect tensile-strength, and California Bearing Ratio tests were conducted for a rangeof RAS contents. Increasing the percentage of RAS by dry unit weight caused a decrease in the optimum moisture content (OMC) and maximum dry unit weight of the soil-RAS mixture. Samples compacted and tested at or below OMC generally experienced a decrease in tensile strength and unconfined compressive strength. However, mixtures compacted wet of optimum with RAS contents of 10 and 20% experienced slight increases in unconfined compressive strength compared to the unaltered soil. California Bearing Ratios from uncured and un-soaked samples consistently decreased with increasing RAS content. Although addition of the recycled shingles did not result in an increase in strength properties for the particular soil type tested, the effect of decreasing the unit weight accompanied by only a moderate loss of compressive strength may make it useful as a recycled lightweight fill material. The reduction in strength properties of the loess with the addition ofRAS results in it not being acceptable for use in soil modification for pavement systems.
Abstract