A review of effect of compaction methods on cold recycling asphalt mixtures

The application of recycled asphalt materials in pavement rehabilitation has been created and developed in the past several decades. The consideration of sustainable practices become more widespread in the road construction. As one of the recycling technology, cold recycling has been mentioned more frequently. Several countries proposed their own quality requirements and mix design procedure for cold recycling mixture. The focus of this paper is the effect of compaction methods on cold recycling mixtures (CRM). Variety of topics including laboratory compaction methods, mechanical performance, microsturcture, relation to field compaction and environmental, economic benefit of CRM are reviewed to better follow up the development of the cold recycling technology. The result indicates that the number of air voids in gyratory and vibratory specimens is more than other compaction, the average air void size is smaller. In terms of environmental and economic benefit, the VVTM was found to exist higher evaluation among these compaction methods. However, the internal structure and mechanical properties of laboratory CRM cannot fully replicate those of field cores. In further study, optimizing compaction process including compaction and double second compaction needs to be considered.