Improved jointed concrete pavement designs through field observations

This paper will provide specific recommenda~ions for the improvemen~ of jointed concre~e pavement design practice. Tbe recommendations will be based upon findings from a major nationwide research project recen~ly completed in the USA concerning field observations of pavement performance. A concre~e pavement performance database was established and extensive data collected from seven different geographic areas on over 400 inservice pavements. The pavemencs vary widely in age, traffic, climate and design. The system is called COncrete Pavement Evaluation System (or COPES) and is a computerized database capable of collecting, storing, retrieving and analyzing jointed plain, jointed reinrorced and continuously reinforced concrete pavements. The results of the study demonstrated that it is possible to obtain valuable information through the evaluation and analysis of in-service concrete pavement data. This capability facilitates the development of broad based design and other recommendations to be used by agencies for improving concrete pavement technology. Some of the topics to be addressed in ,design recommendations include the following : - slab thickness - joint spacing - dowel diameter - tied concrete shoulders - stabilized base materials - slab reinforcement - subdrainage through subdrains and subgrade drainage - maintenance of transverse joint seals - increased Portland cement concre~e modulus of rupture - climatic factors (temperature, moisture) - traffic level. Predictive models of pavement distress (cracking, joint deterioration, pumping, faulting) and rideability (PSR) were developed. These models were developed at the local (state) level and at the national level. They provide a wealth of information on illustrating the performance of different pavement designs in different climatic zones. This paper will attempt to summarize the key results from the overall study for jointed concrete pavement.