Experimental and Numerical Investigation of Using Waste Glass Aggregates in Asphalt Pavement to Mitigate Urban Heat Islands

Abstract

In this study, the experimental and numerical effects of using waste glass as aggregates of asphalt pavement are evaluated. The main reason for using this waste material as aggregates of hot mix asphalt (HMA) was to alleviate an environmental problem associated with asphalt pavements called urban heat islands (UHI). This phenomenon can increase the temperature in urban areas compared to their suburbs. Regarding the experimental part, two different HMA mixtures containing 100% limestone aggregates (HMAL) and 100% glass aggregates (HMAG) were made. An experimental setup was used to simulate the solar radiations on top of HMA specimens. As a result, thermal parameters, including thermal conductivity, thermal diffusivity, and specific heat capacity, were measured and calculated using the heat transfer equations and the heat transfer test. These results were then used to develop finite element models for two different pavement structures with different asphalt concrete layers (one of them with HMAL and the other with HMAG). Furthermore, the air temperature data, extracted by TRNSYS software for Bechar city in Algeria, was used for modeling. The surface temperature, first, second, and third interface temperatures in the asphalt pavement were obtained. The results revealed that using this waste aggregate increased the surface temperature during the day, which can make it susceptible to rutting. However, it reduced the surface temperature at night. More importantly, the HMAL absorbed 34 % and released 47% more heat than HMAG during days and nights. Hence, the HMAG performance can mitigate the UHI effects. Moreover, using this waste material as aggregates in HMA can introduce a recycling method with low costs.