Study on dynamic responses of particle in aggregate mixture during the laboratory compaction utilizing Smart Aggregate

Abstract

Knowing compaction process of pavement at meso-scale is of great significance for improving the material design and construction quality. This study aims to investigate dynamic responses of particle in aggregate mixture during compaction by using a Smart Aggregate. As the compaction method and material composition have significant influence on dynamic responses of the particle in compaction process, various compaction methods, including impact, vibration, static and gyratory compaction, were first conducted on lubricated mixtures in the laboratory. Then, number of contact points and movements of the Smart Aggregate in mixture were analyzed in different stages of gyratory compaction process. Additionally, effects of critical influencing material factors, including lubrication effect, particle size, aggregates packing and gradation on the particle movement in mixture were discussed. Results indicate that the dynamic responses (i.e. acceleration, rotation and contact force) of the Smart Aggregate exhibited significant relation to the loading mode of compaction efforts. Regarding to gyratory compaction, drastic particle movement and sharp increase in number of contact points mainly occurred in the first stage in which the reduced height of specimen was more than 1 mm. Although lubrication had a marked impact on compaction of aggregates system, its influence on movement could be negligible for the Smart Aggregate. Those adjacent aggregates with particle size less than 4.75 mm performed well in terms of restricting the movement of the Smart Aggregate. After filling fine aggregates with particle size less than 2.36 mm into packed aggregates, the deviation of change in acceleration amplitude and relative rotation was reduced to a low level. Compaction methods, adjacent particles’ size and aggregates packing had significant influences on the dynamic responses of the Smart Aggregate.