The effect of insulation layers on pavement strength during non-freeze–thaw season

This paper examines the effect of integrating insulation layers on pavement strength using falling weight deflectometer testing data conducted on an instrumented test road in Edmonton, Alberta, Canada. The insulated sections of this road consisted of a -metre-thick bottom ash layer and two polystyrene layers at thicknesses of 5 and 10 cm, while the adjacent conventional section functioned as the control section (CS). For the purpose of strength comparison, the effective modulus and structural number of insulated sections were compared to a conventional CS in a non-freeze–thaw season. The durations of pavement freezing, recovering and fully recovered (non-freeze–thaw) periods were established by monitoring the moisture variations in different pavement layers. The results indicated that using insulation layers generally reduces pavement strength, and this reduction is more pronounced in the insulated section with thicker polystyrene.