Effects Of Anti-stripping Agents Research Articles

Study of Anti-Stripping Measures to Improve the Adhesion of Asphalt to Granite Aggregates

Granite is very widely distributed in the world, but granite is an acidic aggregate with poor adhesion to asphalt. In untreated asphalt mixtures, asphalt pavement water damage and loose disease are more prominent, affecting the service life of the pavement and service level. Enhancing the road performance of granite asphalt mixture generally improves the adhesion properties of asphalt and granite. Qingchuan rock asphalt, anti-stripping agent KH5, aliphatic amine anti-stripping agent AJ-1 and two groups of the composite anti-stripping agents were used to modify the asphalt and analyze the effect of different anti-stripping agents on the improvement of asphalt-granite aggregate adhesion properties based on the surface free energy (SFE) theory. Second, the effect of anti-stripping agents on the rheological properties of asphalt were analyzed by rheological tests, and the modification effect of granite asphalt mixture road performance was evaluated by Marshall tests. The aging of asphalt and asphalt mixture was simulated by thermal oxygen aging, and the durability of different anti-stripping agents was investigated by comparing the performance of asphalt and asphalt mixtures before and after aging. The results showed that Qingchuan rock asphalt can effectively enhance the high-temperature stability and anti-aging properties of asphalt mixes, but the low temperature performance was relatively poor. KH5 and AJ-1 can make up for the lack of low temperature performance of rock asphalt, but the water stability of asphalt mixes decreases after aging. All five groups of anti-stripping agents improve the adhesion of granite-asphalt and the water stability of the asphalt mixture to some extent. Considering the aging effect, the order of granite-asphalt mixture water stability is: KH/RAMA > AJ/RAMA > RAMA > KHMA > AJMA.

Effects of anti-stripping agents on the microscopic strength of mineral aggregate contact surface

This study investigated the effects of types I and II anti-stripping agents on the microscopic strength of the mineral aggregate contact surface of mixture. Panjin70# bitumen and SBS-modified bitumen were used as binders and granite acid stone was used as the aggregate. Microscopic strength covers the total strength of the contact surface, adhesion strength between the aggregate and bitumen, and the cohesive strength of the bitumen binder. Microscopic strengths were tested after short-term aging (RTFOT) and long-term aging (RTFOT+PAV). Results show that the enhancement effect of type I anti-stripping agents on adhesion was weakened after aging treatment, but anti-stripping agents exert no remarkable influence on cohesive strength under such treatment. Short-term aging treatment has slightly influence on enhancement effect of type II anti-stripping agents on adhesion, but the enhancement effect on adhesion was not obvious after long-term aging treatment and cohesive strength of bitumen significantly decreased at low temperature, thereby markedly diminishing total strength. Anti-stripping agents may influence adhesive and cohesive strengths of bitumen, choosing the anti-stripping agents should seriously considering the compatibility between anti-stripping materials and bitumen.

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.