Abstracts Earth and Environmental Sciences

The skid resistance of asphaltic pavements using glass aggregates

by Michael Vaughn Korth

"The disposal of the glass portion of solid waste is an ever-growing problem in the U.S. and recycling has been suggested as a possible solution. In order to find new uses for waste glass, investigations have been conducted to determine if the glass could be used as an aggregate in bituminous concrete mixtures. As part of the overall investigation, this study was concerned with investigating the skid resistance properties of the glass aggregate mixtures, called glasphalt. The objectives were to compare the skid resistance of various bituminous mixtures using aggregate combinations ranging from all glass to all conventional aggregate and to determine if the skid resistance is high enough to permit safe vehicle operation under wet road conditions. The major portion of the testing consisted of taking wet skid resistance measurements using a British Portable Skid Resistance Tester at two field installations located near the University of Missouri-Rolla. One installation consisted of ten 1-1/2 by 1 foot test patches, two patches for each of five different mixes, placed in a street near the Rolla campus. The mixes used included one consisting of all glass; one of river gravel and glass; one of river gravel and river sand; one of crushed rock and glass; and one of crushed rock and river sand. The other installation was a 561 foot long, 20 foot wide section of glasphalt overlay placed on an access road to the University general services building. Both installations were placed during the summer of 1970 and skid resistance measurements have been taken at intervals since then. Some additional data has been collected for glasphalt field installations in three other states and Canada. It was concluded that an asphaltic pavement using all-glass aggregates will give a lower skid resistance than a conventional aggregate pavement using the same gradation of material. No conclusions could be drawn concerning the effect on skid resistance of substitution of glass for the sand size aggregate in asphaltic pavements. Based on data taken at intervals ranging from one day to one year after the pavement was placed, it was determined that glasphalt pavements could provide adequate skid resistance for speeds lower than about 40 mph" – Abstract, leaves ii-iii.