Laboratory investigation on cooling effect of multi-layer phase change asphalt concrete
To investigate the cooling effect of multi-layer phase change asphalt concrete structure,the phase transition temperatures of five groups of polyethylene glycol(PEG)with different molecular weights were measured by differential scanning calorimetry.Seven groups of three-layer composite asphalt concrete slabs containing PEG were prepared based on the simulation results of asphalt pavement temperature field under solar radiation.The internal temperature of these composite asphalt concrete slabs within 9 h of thermal radiation was measured using the self-developed thermal radiation and temperature measurement device.And the effects of PEG addition layer,combination of PEG addition layer and molecular weight on the heat storage and cooling of composite asphalt concrete slabs were analyzed.Results show that the starting temperature of phase transition increases from 25.1 ℃ to 54.4 ℃ with the molecular weight of PEG increasing from 1000 to 6000.The cooling effect is mainly reflected in the mixing layer and its lower layers when phase change material was added to the single layer of pavement structure.The scheme of adding PEG in the upper layer is better than that of using PEG in multiple layers from cost performance.The cooling effect of PEG with high molecular weight is better than that of PEG with low molecular weight at the same content.