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This paper summarizes a multi-year effort comparing the new-generation wide-base tires (NG-WBT) and dual-tire assembly from a holistic point of view. The tires were compared considering not only pavement damage but also environmental impact. Numerical modeling, prediction methods, experimental measurements, and life-cycle assessment were combined to provide recommendations about the use of NG-WBT. A finite element (FE) approach considering variables that are usually omitted in the conventional analysis of flexible pavement was used for modeling pavement structures combining layer thickness, material properties, tire load, tire-inflation pressure, and pavement type (interstate and low volume). A prediction tool, ICT-Wide, was developed based on an artificial neural network to obtain critical pavement responses in cases excluded from the FE analysis matrix. Based on the bottom-up fatigue cracking, permanent deformation, and international roughness index, the life-cycle energy consumption, cost, and green-house gas emissions were estimated. To make this research useful for state departments of transportation and practitioners, a modification to AASHTOware is proposed to account for NG-WBT. The revision is based on two adjustment factors, one accounting for the discrepancy between the AASHTOware approach and the FE model of this study, and the other addressing the impact of NG-WBT. Although greater pavement damage may result from NG-WBT, for the analyzed cases, the extra pavement damage may be outweighed by the environmental benefits when NG-WBT market penetration is considered.

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Three-dimensional tire–pavement contact loads of two truck tires–-a new-generation wide-base tire (WBT) and a dual tire assembly (DTA)–-were measured and analyzed. Extreme and typical values of tire inflation pressure (552, 690, 758, and 862 kPa) and tire loading (26, 35, 44, 62, and 79 kN) were considered in the experimental program. The measurements were performed with the stress-in-motion Mk IV system at the Council for Scientific and Industrial Research in South Africa. Peak values in three directions were compared, and the importance of tangential contact stresses was highlighted. In addition, characteristic variations of the measurements in the longitudinal, transverse, and vertical directions were identified. A function depending on two regression parameters, applied load, and distance along the contact length was proposed to represent the contact load in the vertical and transverse directions. An analysis was performed on the measurements to obtain the regression parameters, and a simplified procedure was proposed to determine tire–pavement contact loads. The contact area and contact length of the WBTs and the DTA were also compared.

The pavement responses obtained from the validated finite element modeling of new-generation wide-base tires (NG-WBTs) and a conventional dual-tire assembly (DTA) are presented. Features of the adopted finite element model, such as three-dimensional contact forces, dynamic analysis, and nonlinear anisotropic base materials, are not considered in the conventional analysis of flexible pavements. Furthermore, the input for the model was intended to simulate a large range of scenarios for the national pavement system. The NG-WBT showed consistently higher pavement responses than the DTA, and the difference decreased as pavement thickness increased. (Pavement thickness varied from 225 to 1,012.5 mm.) The average percentage difference of the longitudinal tensile strain at the bottom of the asphalt concrete layer was 14.7% and 23.2% for thick and thin pavements, respectively. In a few cases of vertical shear strain in the subgrade for thin pavement, the response was higher for the DTA than for the NG-WBT. For the same responses in thick pavement, the average percentage difference was 4.4%. If critical pavement strains are used as inputs into transfer functions, which estimate pavement life, results of this study could serve as indicators of increased potential damage when NG-WBTs are used. However, market penetration of the NG-WBT and its use within the truck axle configuration need to be taken into consideration. Additionally, environmental and economic benefits of using NG-WBTs may offset the potential increase in pavement costs.

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