Continued monitoring of SHRP pavement instrumentation including soil suction and relationship with resilient modulus

"June 2004."; Executive summary laid in.; Includes bibliographical references.; Final report.; Performed by Ohio State University, Dept. of Civil and Environmental Engineering and Geodetic Science Sponsored by the Ohio Department of Transportation, prepared in cooperation with the U.S. Department of Transportation, Federal Highway Administration under state job no.; Harvested from the web on 3/21/06Test pavements constructed by the Ohio Department of Transportation (ODOT) on U.S. 23 in Delaware, OH were studied. Environmental data collected from 1997 to 2003 at five test locations are presented. Also, porewater pressures in the near surface soils beneath select pavement sections were measured. These measurements showed that pore pressures in the soil under the pavement have continued to increase over time strongly suggesting that the subsurface soils quickly became saturated as water was drawn up into the profile. Models used to predict the resilient modulus of cohesive subgrade soils typical of those found in Ohio were evaluated. The current study consisted of performing a series of static laboratory tests to determine the soil's engineering properties. These tests were followed by the direct measurement of the resilient modulus. Tests were performed on both unsaturated and saturated soil samples. The moduli as predicted by these existing methods were compared with the measured values. An improved and more accurate resilient modulus prediction model has been developed and validated in this study. Results obtained from M[subscribt r] laboratory testing show that for cohesive soils, the water content, the applied deviator stress, the confining stress and the unconfined compressive strength all affected the resilient modulus of the sample. The resilient modulus values of the saturated soil samples were, in most cases, less than half that of the modulus at optimum moisture content.Test pavements constructed by the Ohio Department of Transportation (ODOT) on U.S. 23 in Delaware, OH were studied. Environmental data collected from 1997 to 2003 at five test locations are presented. Also, porewater pressures in the near surface soils beneath select pavement sections were measured. These measurements showed that pore pressures in the soil under the pavement have continued to increase over time strongly suggesting that the subsurface soils quickly became saturated as water was drawn up into the profile. Models used to predict the resilient modulus of cohesive subgrade soils typical of those found in Ohio were evaluated. The current study consisted of performing a series of static laboratory tests to determine the soil's engineering properties. These tests were followed by the direct measurement of the resilient modulus. Tests were performed on both unsaturated and saturated soil samples. The moduli as predicted by these existing methods were compared with the measured values. An improved and more accurate resilient modulus prediction model has been developed and validated in this study. Results obtained from M[subscribt r] laboratory testing show that for cohesive soils, the water content, the applied deviator stress, the confining stress and the unconfined compressive strength all affected the resilient modulus of the sample. The resilient modulus values of the saturated soil samples were, in most cases, less than half that of the modulus at optimum moisture content