New AASHTO Equivalency Factors of Tracked Armoured Vehicles on Flexible Pavement

Abstract

Presented in this paper is a study to find new AASHTO equivalency factors of military tracked armoured vehicles on flexible pavement. Two types of military tracked armoured vehicles were studied, namely M1A1 tank and M113A3. A measure of the damaging effect of military tracked armoured vehicle loads was achieved by correlating their equivalent loads with the AASHTO equivalency factors. The equivalent load was developed on the basis of mechanistic - empirical approach. It was found that the damaging effect of the studied military tracked armoured vehicle loads is 0.016 to 19.4 times the damaging effect of the standard 18 kips (80 kN) axle load depending on the thickness of asphalt layer. It was found that the damaging effect of military tracked armoured vehicle loads on flexible pavements of major highways and main principal roads is much more than its damaging effect on the flexible pavement of local and secondary roads. It was found also, that tracked armoured vehicles have a severe damaging effect on the functional serviceability of surface asphalt layer in terms of deformation and strains due to the effect of relatively rigid track chain.