Compaction performance of cold recycled asphalt mixture using SmartRock sensor

Due to the lack of essential understanding of the interaction mechanism between the aggregates under compaction, engineering problems such as uneven compaction and over-compaction are prone to occur. This paper presents three indicators to quantitatively evaluate the characteristics of cold recycled asphalt mixture at different compaction stages, and develops a novel method to determine the locking point of the mixture. The stress, rotation and acceleration changes of aggregates under gyratory compaction can be continuously monitored by SmartRock sensor. By analyzing these dynamic responses, the compaction workability, skeleton strength and stability of the mixture are analyzed. Results showed that by a combined use of SmartRock and the new evaluation indexes, the compaction state of the mixtures can be accurately captured and monitored by looking closer into the microstructural changes of asphalt mixture. It is recommended to further advance the application of embedded sensors in field conditions and in that, to achieve a global monitoring of compaction response the array layout design of sensors inside pavement structure could be an important focus of next stage. • A new method for compaction process evaluation based on SmartRock is developed. • New indexes are proposed to accurately characterize the different compaction stages. • The locking point of the mixture can be reliably determined by SmartRock. • The sensitivity of compaction state to different factors is captured by SmartRock.