Effect of chemical additives on the binding strength of Arabian Asphalts

Premature deterioration of asphalt highway pavements in Saudi Arabia have considerably reduced their service lives, sacrificed rider comfort, and increased maintenance costs. The physicochemical phenomena as well as the long-range effect of the interstitial asphalt on the asphalt-aggregate bond plays a vital role in determining the stripping properties of aggregates. Chemical additives, known as antistripping agents, were mixed with asphalts to study their enhanced bonding capabilities with aggregates. Three antistripping agents that are locally available were used in this study. The results indicated that the adsorption of Riyadh asphalt on Riyadh aggregates is greatly increased with all three antistripping agents. Taif aggregates have also shown a substantial increase in their adsorption behavior due to the presence of antistripping agents. Similarly, the amounts of Restaurant asphalt remaining adsorbed after aggregates were coated with antistripping agents were found to be significantly higher than uncoated aggregate samples. The antistripping agents were found to promote stronger bonding, resulting in less asphalt desorption by water. This study provided important information regarding the effect of antistripping agents on the adsorption and desorption behavior of Arabian asphalts and asphalt-aggregate systems. The overall results were interpreted with regard to their usefulness in finding solutions to pavement damage problems in Saudi Arabia.