Institute for Transportation

About the research

The impacts of curling and warping on long-term pavement performance are not well understood. While some recent studies have pointed to a strong connection between the two, others have stated that these findings may not be as significant as first thought. At the same time, we continue to seek out more cost-effective ways of designing and constructing pavements without sacrificing performance. In order to do this, the curling and warping relationship must be better understood.

It is of paramount importance to measure the actual magnitude of curling and warping taking place in concrete pavements in order to develop performance measures and critical threshold magnitudes and gain a better understanding of their relationship to diurnal and seasonal temperature/moisture changes and long-term pavement performance.

In the recently completed Iowa Highway Research Board (IHRB) Project TR-668: Phase I by Dr. Halil Ceylan and his research team, “Impact of Curling and Warping on Concrete Pavement” (Phase I), field investigations were performed at six identified sites in Iowa highways to better understand the curling and warping behavior of portland cement concrete (PCC) pavements in Iowa and provide recommendations to mitigate PCC curling and warping. The results and findings were correlated to pavement performance, mix design, pavement design, and construction-related variations at each site.

However, the PCC pavements investigated in IHRB Project TR-668: Phase I were mainly selected from Iowa highways whose pavement design features were different from those of Iowa county and city roads (e.g., thinner PCC slabs). It is important to note that thicker and shorter PCC slabs can result in a relatively lesser degree of curling and warping compared to the thinner and longer slabs. In addition, the number of PCC pavements selected and relevant data collected were not sufficient for validating the recommendations derived from the literature review findings. For example, the curling and warping literature suggested that water absorption of coarse aggregate is one of the significant mix design variables affecting warping degree/magnitude, but little reported information currently exists on water absorption of coarse aggregate used in Iowa PCC pavements to validate this literature review finding. Thus, a more comprehensive follow-up study on the impact of curling and warping on Iowa concrete pavement was recommended.