Construction Cycle Four (CC-4) was an initiative of The Innovative Pavement Research Foundation (IPRF). It was undertaken to improve the understanding of the influence of design parameters on unbonded concrete overlays of airfield pavements, thus enabling improvement of design methodologies. The Baseline Experiment was developed to address the following:

• Overly response.
• Effect of underlying discontinuities on overlay response.
• Relative deterioration of the overlay and underlying pavement after trafficking.
• Deteriorations in terms of distress and structural response as compared to SCI Model.

The CC-4 pavement involved the replacement of three concrete test items, three transitions and an asphalt overlay of the CC-2 pavement extending from station 300 to 600. Removals reached a clean medium strength subgrade (DuPont Clay) about 2 ft. below the designed top surface of the CC-4 concrete overlay.