The effects of coarser sand addition on thermal properties of pervious concrete

Pervious concrete (PC), characterized by its high porosity, is an effective solution for urban challenges such as mitigating urban heat island effects and managing stormwater in developed areas. Fine aggregates significantly influence the properties of pervious concrete. This study examines the impact of incorporating various percentages (0–20% in 5% increments) of coarse sand (CS) into the aggregate mix on the specific heat and volumetric heat capacity of PC, as well as the heat storage capacity of pavement systems when it used as paving material. The investigation also analyzed one-dimensional heat flow in a controlled environment. Volumetric heat capacity is measured using calorimetry (CM) and porosity-based methods (PM), while heat storage capacity is assessed by analyzing the different layer’s temperatures within the pavement system. Results indicate that adding of CS increases density and compressive strength while decreasing porosity and permeability, though these changes are not linear. The initial 5% addition of coarser sand shows a significantly higher increase in specific heat and volumetric heat capacity than subsequent additions. Adding CS from 0 to 20% perfectly maintained the standard porosity range of the PC, leading to a 26% increase in ultimate heat storage capacity in the CM method and a 9% increase in the PM method. The one-dimensional heat release analysis reveals that pervious concrete with a higher percentage of CS dissipates heat more slowly, taking longer to reach a specific temperature than concrete with lower CS content. These methodologies can be applied to assess the thermal properties of flexible and traditional rigid pavement systems.