Application of Conductive Materials to Asphalt Pavement

Abstract

Snow-melting pavement technique is an advanced preservation method, which can prevent the forming of snow or ice on the pavement surface by increasing the temperature using an embedded heating system. The main scope of this study is to evaluate the impact of conductive additives on the heating efficiency. The electrical resistivity and thermal conductivity were considered to investigate effects of conductive additives, graphite, and carbon fibers on the snow-melting ability of asphalt mixtures. Also, the distribution of the conductive additives within the asphalt concrete body was investigated by microstructural imaging. An actual test was applied to simulate realistic heating for an asphalt concrete mixture. Thermal testing indicated that graphite and carbon fibers improve the snow-melting ability of asphalt mixes and their combination is more effective than when used alone. As observed in the microstructural image, carbon fibers show a long-range connecting effect among graphite conductive clusters and gather in bundles when added excessively. According to the actual test, adding the conductive additives helps improve snow-melting efficiency by shortening processing time and raising the surface temperature.

Electrically-conductive asphalt mastic: Temperature dependence and heating efficiency

“…It is worth noting that, all the weights presented in Table 2, were calculated with the aid of SG values provided in Table 1. According to literature, conductive fillers can be incorporated in asphalt-based materials by following either dry [7], [27], [28] or wet [29], [30] mixing method. In dry mixing method, all 19 the components including the conductive filler are mixed at a temperature range of 150-160°C 20 [7], [27], and in wet mixing method, the conductive fillers are first blended with bitumen at an 21 elevated temperature range of 170-180°C [29], [30], and then the modified bitumen is mixed 22 with other components.…”

“…According to literature, conductive fillers can be incorporated in asphalt-based materials by following either dry [7], [27], [28] or wet [29], [30] mixing method. In dry mixing method, all 19 the components including the conductive filler are mixed at a temperature range of 150-160°C 20 [7], [27], and in wet mixing method, the conductive fillers are first blended with bitumen at an 21 elevated temperature range of 170-180°C [29], [30], and then the modified bitumen is mixed 22 with other components. Increasing the mixing temperature increases the oxidation of bitumen 23 [31]; as a result, to reduce the bitumen oxidation, dry mixing method was utilized in this study, and using a rotational viscometer -and following the ASTM D4402 standard [32] -the 1 minimum mixing temperature of PG 58-28 was determined as 145°C.…”

“…shear during the mixing process enhancing the conductive material dispersion quality. The absence of non-conductive fillers and aggregates is the reason for having the elevated mixing temperature range of 170-180°C in wet mixing method [29], [30]. Our claim is consistent with the findings of Liu, et al, [27], who mixed the still wool in asphalt concrete (ECAM + aggregates) at 160 °C to produce electrically conductive porous asphalt concrete for self-healing applications; the applied shear by aggregates during the mixing process helped enhancing the conductive material distribution and hence avoiding using a high mixing temperature.…”

Carbon Nanomaterials for Enhancing the Thermal, Physical and Rheological Properties of Asphalt Binders

“…Vo, H.V. and Park [ 13 ], Tang et al [ 14 ] found that the cooperation of graphite and carbon fiber contributed to more remarkable thermal conductivity increments compared to their individual properties, after partially substituting mineral filler due to the formation of conductive networks in asphalt concrete. Furthermore, the effectiveness of various combinations of graphite, carbon black and carbon fiber for improving the thermal conductivity of solar harvesting and snow melting pavements was validated in the study of Bai et al [ 15 ].…”

Laboratory Evaluation of Electrically Conductive Asphalt Mixtures for Snow and Ice Removal Applications

“…Huang et al (8) reported that conductive additives in powder form are added in much higher quantities than fibrous additives to bring the electrical conductivity to the same level. Bai et al (12) and Vo and Park (9) reported that graphite (powder form) is added into asphalt mixes in dosages of 5% to 20% by volume of asphalt binder. In the case of fibrous additives, Vo and Park (9) utilized carbon fiber dosages of less than 5% by volume of asphalt binder.…”