Thermal Properties of Base-Course Material Containing Recycled Glass Under Dry and Wet Condition

The increasing need to recycle waste and reduce the use of landfills has led to the reconsideration of the use of recycled glass aggregates in pavement construction. While the mechanical and hydraulic performances of recycled glass aggregates (RGA) in roadwork applications are well documented, their thermal performance is almost unexplored. However, in cold regions, the adequate thermal design of pavement relies on a good prediction of the thermal regime in the road structure. Glass is known for its insulating or heat-retention properties (low thermal conductivity). Aggregates and aggregate mixtures with low thermal conductivity can help decrease the depth of frost penetration. This experimental study aimed to evaluate the thermal properties of RGA blended with natural aggregate (NA). In this paper, we present the results of thermal conductivity and thermal diffusivity measurements on RGA, NA and NA blended with RGA (NA/RGA). Our methodology included the influence of particle size, moisture content and glass content. At a given moisture content, the thermal conductivity of RGA and NA decreased with increasing particle size. The results show that an increase of water content in any of the studied material increased its thermal conductivity but at relatively different rates. It was also found that increasing the percentage of glass in NA/RGA blends decreased their thermal conductivity.