Impact of farm equipment loading on low-volume concrete road structural response and performance

The rapid increase in farm equipment size in the United States of America agricultural industry has raised significant concerns regarding its impact on the low-volume road infrastructure. The study described in this paper investigated the impact of heavy farm equipment (or agricultural vehicle) on the structural behaviour of rigid pave­ment system. A series of full-scale traffic tests were conducted at the Minnesota’s Cold Weather Pavement Testing Facility (more commonly known as MnROAD) on two existing low-volume rigid pavement sections: (1) to study the effects of agricultural vehicle and weights, traffic wander pattern, pavement structure, and environmental factors on rigid pavement responses (deflections, strains and stresses), and (2) to compare these responses with those of a standard 356 kN (80 kips) five-axle, semi-trailer truck for assessing relative rigid pavement damage caused by heavy farm equipment. Numerical analyses were also carried out for rigid pavement fatigue damage estimations by simulat­ing field test conditions. The Finite Element Model was able to predict rigid pavement responses under complicated heavy agricultural farm equipment loading. The study findings revealed that seasonal change, traffic wander, vehicle loading/configurations, pavement thickness, slab length and modulus of subgrade support are all important factors to be considered in designing rigid pavement subjected to heavy farm equipment loading. The use of tandem or tri­dem axles is recommended for all farm equipment because those axles help to distribute the load and minimize rigid pavement damage.