Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/119545
���Through field measurements on pavement test sections with both conventional and alternative designs, the thermal behavior and cooling effect of permeable asphalt pavements under both dry and wet conditions were investigated,��� say Li, Harvey and Jones . The researchers found the overall sevenday average cooling effect of wetting once on permeable pavements for near-surface air is approximately 0.2 to 0.45 degrees C [0.36 degrees F to 0.81 degrees F]; for the surface it is apindustries. The authors address this issue, saying it���s not so proximately 1.2 to 1.6 degree C [2.16 to 2.88 degrees F]; and simple. approximately 1.5 to 3.4 degrees C [2.7 to 6.12 degrees F] for ���With respect to the pavement type, the heat island might the in-depth layers. not be a ���black and white��� issue (asphalt vs. concrete) as being ���Based on the findings, permeable asphalt pavements have argued in the pavement industry, but might be an ���impervious the potential of being a type of cool pavement which proand pervious��� issue,��� they say. ���To mitigate heat islands and duces lower temperatures and thus helps improve the thermal reduce the associated impacts, some impervious surface coverenvironment and mitigate the heat island effect,��� they write. age should be substituted by pervious coverage.��� ���However, attention should be given to this type of pavement The minimized impervious surfaces could potentially under dry conditions. As a pavement thermal management improve the quality of life in a community and reduce other strategy, water from rain or irrigation systems might need to environmental impacts, such as reduced stormwater runoff be applied to the pavements to produce a better cooling effect and associated water pollution, reduced stormwater managefor improving the thermal environment and mitigating the ment facilities, and enhanced on-site infiltration for vegetation heat island.��� growth, recharging the underground water, they say. v These permeable pavements can be used in city streets, parking lots and highway shoulders, and the type of surface could potentially enhance the evaporation from pavement, Introducing from while the cooling effect depends on the moisture content and evaporation rate, they say. ���Beyond reducing temperature, permeable pavements also could potentially reduce the air/pavement noise due to reduced air pumping under high speed, and improve high-speed driving safety through reducing splashing and hydroplaning during rain,��� they say. ���Also, full depth permeable pavement could reduce stormwater runoff and improve water quality. However, permeable pavements also could possibly increase fuel consumption of vehicles due to higher rolling resistance caused by the rougher Fully-Integrated Construction surface.��� Permeable pavements are posApps That Handle Real Work sibly not suitable for high speed and heavy-duty facilities such as highways ��� Time cards ��� Job site photos & notes and airfields due to their relatively lower Innovative Estimates & proposals structural capacity, they add. ��� ��� GPS location of trucks Software for the The issue of whether rigid (white) or ��� Change order estimates ��� Alerts, reports, & much more! Construction Industry flexible (black) pavement is the ���coolest��� pavement medium has been raging 800-683-3196 ��� Designed for construction ��� Constant internet not required for years between the portland cement www.hcss.com/apps ��� Flexible technology ��� Integrates with accounting concrete and the bituminous concrete Permeable pavements include permeable asphalt pavements, porous concrete pavements, pervious cast concrete pavement, and interlocking concrete pavements Innovative Mobile Apps HCSS Text INFO to 205-289-3789 or visit www.betterroads.com/info Better Roads April 2013 29 RoadScience_BR0413.indd 29 4/1/13 3:28 PM