Evaluation on Aggregate Particle Spalling of Induction Heating‐Based Functional Ultra‐Thin Friction Layer Using Image Processing Based on MATLAB

ABSTRACT Induction heating‐based functional ultra‐thin friction layer (FUFL) for removing snow and ice was found severe aggregate spalling due to repeated induction heating. This study tried to reveal how induction heating affects FUFL's resistance to particle spalling through an originally developed assessment through computer image processing. Firstly, AC‐5 asphalt mixtures incorporating steel slag and steel fibers were designed. Secondly, an abrasion‐spalling accelerating device and an evaluation method based on image processing of MATLAB were proposed to assess the spalling level, reflecting changes of spalling level by measuring the change rate of the black pixel percentage. Finally, a quantitative analysis of how induction heating determines particle spalling degree by ice melting time dependence was performed. Results illustrated that steel slag can enhance the splitting strength, stability, interlayer shear strength, improve the induction heating rate and ice melting effect, but also exacerbate the particle spalling. The developed evaluation method was adequate in assessing aggregate spalling. Aggregate spalling degree of FUFL was positively correlated to the number of freeze‐thaw cycles. It was found that the comprehensive road performance, induction heating performance, and spalling performance of FUFL could be optimally enhanced by adding 1% steel fibers.