Since low-volume road (LVR) systems were first designed and built, events such as deregulation and free-trade agreements and changes in economic growth patterns and in manufacturing and farming practices have resulted in increased truck movements and have accelerated the deterioration of paved LVRs, such as the ones in North Dakota, which were not designed for such heavy-truck traffic. The traditional empirical methods--use of the soil factor and R-value designs and the use of visual inspection and ride quality--to assess pavement performance are not adequate. A mechanistic model that uses material data and is capable of predicting pavement response under different traffic loading and seasonal conditions is deemed necessary. An analytical approach to determine and compare pavement response for different truck axle loadings under normal, thaw, and hot summer seasonal conditions on paved LVRs is discussed. A three-dimensional finite element program is used to model the pavement response in the form of total permanent deformation (TPD) and to calculate axle and truck damage factors. Various axle loadings representing U.S. axle weight limits on steering axles with single tires, single axles with dual tires, tandem axles, and tridem axles are used in this study. Seasonal variations are modeled through material strength parameters. The analysis of the TPD responses provides greater insight and understanding of how paved LVRs react to different axle configurations, levels of loading, and seasonal variations. This analysis ultimately may help to improve paved LVR design and planning practices and enhance seasonal load limit criteria.
Abstract