Completed: Sustainable asphalt pavements with recycled concrete aggregate and waste glass

In collaboration with Total Reclaims Demolition Ltd

Asphalt serves as the primary surfacing material for the road infrastructure in the UK, comprising mineral aggregates and bitumen. However, foundation industries in the UK generate a substantial amount of waste concrete and glass, which presents an opportunity to replace the limited natural aggregates. This project focused on integrating recycled concrete aggregate (RCA) and recycled glass cullet (RGC) from the foundation industry into the production of sustainable and high-performance asphalt pavements.

One of the main challenges associated with using recycled aggregate materials is their lower mechanical strength and weaker bonding with bituminous mortar. To address these issues, this project employed two surface treatment methods for RCA: polymer impregnation using polyvinyl alcohol  (PVA) and pozzolan slurry soaking, using either fly ash and silica fume (FA&SF), fly ash and cement (FA&C) or fumed nanosilica (NSF).

a. RCA

b. FA & SF

c. FA & C

d. NSF

e. PVA

The density, water absorption, porosity and surface morphology of RCA were comprehensively assessed before and after the surface treatment. The results show that both surface treatment methods reduce the water absorption and porosity, as well as enhance the microstructure and improve the surface homogeneity of RCA.

Overall, the utilization of RCA (and RGC) derived from the foundation industry holds great promise as a viable alternative to the excessive use of natural aggregates in the construction of future high-quality and sustainable asphalt pavements.

Based on the findings in this project, the PI has secured another grant entitled: “Enabling Construction Material Circularity in the Transport Infrastructure Sector” awarded by Innovation Launchpad Network+ EPSRC in collaboration with Connected Places Catapult. A peer reviewed conference paper has been published: Wang, H., Fang, Y., Wang, F., and Airey, G. (2023) Property enhancement of recycled concrete aggregates through surface treatment. Presented in the 7th Chinese-European Workshop on Functional Pavement (CEW 2023), July 2-4, 2023, Birmingham, UK.

Dr. Haopeng Wang haopeng.wang@nottingham.ac.uk

University of Nottingham