Development of automated electrical heat grid for pavement snowmelt

Snow and ice on airfield pavement threatens aircraft ground operation safety. Plowing and chemical treatment are used for snow removal, but yield long-term detrimental impacts to the airfield infrastructure and environment. In this paper, a "near-surface embedded electrical heating grid prototype" is investigated through laboratory and field testing for concrete pavement heating, providing an airfield pavement anti-icing alternative. The prototype grid, installed on small-scale concrete test mats, was studied in a laboratory controlled below-freezing temperature environment. Testing evaluated pavement surface heating performance under two energy supply methods: (1) an alternating heating sequence and (2) an automated thermostat heating sequence, assessing their ability to (1) raise the pavement surface temperature to an anti-icing temperature threshold, 2 degrees C, and (2) sustain an anti-icing surface temperature. The alternating heating sequence required a low power input, but an increased heating time. Under the automated thermostat heating sequence, with a 152.4 mm parallel heat wire spacing and 667 W/m(2) power input, surface temperature rose from an initial -12 degrees C to 2 degrees C in 4 h, then maintained in the anti-icing range, 2 degrees C to 5 degrees C. Laboratory, preliminary study results directed the construction, instrumentation, and operation of a large-scale prototype slab for field testing. The prototype was built in Fayetteville, AR and subjected to ambient outdoor climate conditions. The full-scale testing used a photovoltaic energy system as the power source. Field testing assessed heating/anti-icing performance and energy consumption. During tests in below freezing air temperatures and snow events, the photovoltaic energy system supplied enough energy to maintain the large-scale prototype slab surface above 0 degrees C.