Long Term Monitoring of Moisture under Pavements

Monitoring of the environmental instrumentation installed under select pavement sections constructed by the Ohio Department of Transportation (ODOT) in 1995 on US 23 in Delaware County, Ohio was continued. The measurements made consisted of soil moisture, temperature and frost depth profiles. Ohio State University constructed and installed tensiometers to directly measure the porewater pressures in the subsurface soils at seven locations at the DEL23 SHRP test road (four during original road construction and three more in 2002). Tensiometers were also installed and monitored at seven additional locations within the state. Those devices were monitored throughout the duration of the current project. A laboratory testing program was conducted to identify relationships between static soil properties and the design resilient modulus for compacted cohesive subgrade soils. Resilient modulus as well as classification and strength tests were performed on cohesive soil samples. The program to establish the relationships between dynamic soil behavior and static properties is described and a predictive tool developed through the use of artificial neural networks is presented.