Rheological and mechanical consequences of reducing the curing time of cold asphalt mixtures by means of magnetic induction

Cold asphalt mixtures are more sustainable because they are manufactured at ambient temperature. However, they are much less applied because they take longer time in the curing process due to the water contained in the asphalt emulsion, which delays the opening of roads. To solve this problem, the option of adding magnetic aggregates to cold asphalt mixtures and heating them by magnetic induction to evaporate the water contained in the asphalt emulsion and reduce curing time has been evaluated. For this objective, different by-products were evaluated as magnetic aggregate and the best one was selected. Four porous asphalt mixtures were then manufactured: an experimental mixture with the selected magnetic particles, a control mixture with virgin steel instead of the by-products, and two oven-cured reference mixtures without magnetic aggregate (one according to the Spanish standard and another according to the U.S. Asphalt Institute guidelines); then, the four mixtures were studied in terms of the curing process, rheological properties of bitumen and mechanical performance of samples. The experimental mixture containing industrial by-products shortened the curing time from 7 and 2 days (Spanish and U.S. Asphalt Institute standard, respectively) to only two hours; rheological and mechanical analysis proved the viability of this technology. ; This publication is part of the project SICA +(Ref. PDC2021-120824-I00), financed by MCIN/AEI/10.13039/501100011033 and by the European Union Next Generation EU/PRTR. The authors acknowledge and thank these institutions. The authors would like to thank Vicente Pérez Mena and María Del Mar Colás of Cepsa Comercial Petróleo S.A. for their collaboration. At the same time, we thank Paula Del Rio Gandarillas and Javier Menocal Allende, whose excellent work in the laboratory gave a fundamental added- value to the development of this research