Thermal profiles in pervious concrete during summer rain simulations

Abstract

Pervious concrete pavement systems may have many environmental benefits including the mitigation of heat island impacts. This mitigation is a complex combination of pervious concrete"s insulating capability and its ability to store water which may provide evaporative cooling. However, the introduction of water may also bring heat into the system, where the system is the pervious concrete pavement layer over an underground aggregate bed for retention and/or detention of stormwater. This study involved three different mix design placements in southern Brazil on a hot sunny summer day. The experiment had a control section and two test spots where controlled artificial rain events were introduced at two times during the afternoon for each of the three placement types. The "rain" initially brought heat from the surface into the pervious concrete layer. Subsequent evaporation cooled these interior pavement layers to levels similar to the control locations. This introduction of water into pervious concrete with very hot surface temperatures in the heat of the day is expected to be a severe condition for adding heat to the system through the flow of water. If water additions are made at different diurnal times, such as nighttime rain, they may provide similar evaporative benefits with less heat transfer into the system via the water phase, and thus even more cooling of the system. These experiments reinforce the conclusion that pervious concrete may be a cool pavement during summer conditions, even under extreme conditions when surface heated stormwater enters the system.

The Effect of Periodic Maintenance on Pervious Concrete Pavements

“…It can be characterised as a rigid pavement solution or used as interlocking paving blocks that allows water infiltration through its porous structure. Thus, pervious concrete helps reduce or eliminate the pollutant load carried to rivers, increases groundwater recharge and also reduces temperatures in urban environments due to lower solar heat absorption [2][3][4]. It is basically composed of Portland cement, narrow grading coarse aggregates and in some cases fine aggregates.…”

Effect of Temperature Difference on the Thickness Design of Pervious Concrete Pavements

“…Based on the temperature data from May 2015 to February 2016, the largest DT was observed in the summer, while the smallest DT was prevalent during the overcast winter conditions. Lorenzi et al (19) evaluated the thermal properties of a 150-mm PCP slab instrumented with thermocouples at mid-depth and the bottom in Porto Alegre, Brazil. The temperature data were collected for 6 h on one summer day with a T ambient ranging from 25°C to 27°C.…”

Effects of Pervious Concrete Thickness on Leachate Water Temperature during Simulated Rain Events

“…As the heat island effect increases within cities in the United States and worldwide, pervious concrete research such as the current research provide data to help us better understand the thermal impacts of our pavement designs. Lorenzi et al (2018) at the University of the Rio Grande in Brazil conducted a study of an existing pervious parking lot instrumented to monitor and collect surface temperatures and evaporation rates to determine subsequent heat transfer. Readings recorded included temperatures taken at the surface, mid-section and collected leachate outflow points from the pervious concrete.…”