The reduced tire pressure could lower the tire-pavement contact stresses and the associated damage to the pavement. A study was carried out by the University of Manitoba to evaluate the effects of reduced tire pressure, in lieu of reduced loads, during the spring thaw period. Asphalt strain gauges were installed in a section of a low volume haul road in central Manitoba. Field testing was conducted in the spring using an 8-axle double semi-trailer equipped with a semiautomated tire pressure control system. The tests were conducted at various loads, truck speeds, and at the normal and reduced tire pressures. The results of the field testing showed that when tire pressure was reduced by fifty percent, the normalized measured tensile strain at the bottom of asphalt layer was reduced by an average of 15%. The effects of the direction of strain, truck speed, and tire offset from the strain gauge were analyzed and presented. A 3-dimension finite element model was developed to simulate the pavement responses to normal and reduced truck tire pressure. The modeling results were verified by field data. The results from both field data and simulation indicated that the tire pressure control system is effective to prevent bottom up failure of the pavement.
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