Concrete overlay of deteriorated asphalt pavements (whitetopping) has been a viable alternative to improve the pavement's structural integrity for over six decades. The thickness of such overlay usually exceeds five inches. In the last few years, however, a newer technology has emerged which is commonly known as Ultra Thin Whitetopping (UTW). UTW is a construction technique, which involves placement of a thinner (than normal) thickness ranging from 2 to 4 inches. he intent of this research study is to identify and address important factors that contribute to the performance of the UTW pavement system. It is also the goal of this research to present an interim design procedure fine tuned by further observation of UTW systems.

The existing ultra-thin whitetopping (UTW) and thin whitetopping (TWT) design methods are reviewed so that any gaps in the design process can be identified. Four design methods are included, namely the Colorado Department of Transportation (CDOT) method, the New Jersey Department of Transportation method, the Portland Cement Association (PCA) method, and the Illinois Centre for Transportation (ICT) method. The structural response and performance models used in these methods are evaluated using field data from the whitetopping sections at MnROAD. Based on these evaluation, the PCA structural model developed for the calculation of stress in the corner and at the top of the overlay seems more suitable for the prediction of the structural response of UTW and the CDOT structural model developed for the calculation of stress at the lane/shoulder edge and at the bottom of the overlay is more suitable for TWT. It is also found that the use of a temperature-dependent asphalt modulus of elasticity results in significantly higher fatigue damage in the overlay, which is ignored by all four methods. Finally, the asphalt fatigue analysis incorporated in some of these design procedures is does not result in fatigue failure of the hot mix asphalt and therefore need not be considered when designing these overlays.

Innovations in Road, Railway and Airfield Bearing Capacity – Volume 3 comprises the third part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field.

Modern highway engineering reflects an integrated view of a road system's entire lifecycle, including any potential environmental impacts, and seeks to develop a sustainable infrastructure through careful planning and active management. This trend is not limited to developed nations, but is recognized across the globe. Edited by renowned authority