R-Value and Resilient Modulus Prediction Models Based on Soil Index Properties for Colorado Soils

Abstract

Resilient modulus (Mr), as an important mechanical property of soil, is used for analysis and design of pavements. Mr can properly describe the stress-dependent elastic modulus of soil materials under traffic loading. In addition to the resilient modulus, R-value test is commonly used to measure the strength of subgrade, subbase, and base course materials for use in pavements. Both tests are expensive and time consuming to run, and establishing accurate and reliable correlations between the test results and soil physical properties can save a considerable amount of time and money in testing and analyzing the construction materials properties. An extensive database of systematically conducted resilient modulus and R-value tests along with basic soil properties for Colorado soils was established. This paper presents the prediction equations developed through (a) regression analysis of over 2600 R-value data points and associated soil basic properties for soil types (A-1-a, A-1-b, A-2-4, A-2-6, A-2-7, A-4, A-6, and A-7-6) and (b) regression analysis of over 200 resilient modulus tests and associated soil basic properties for soil types (A-1-b, A-2-4, A-4, and A-6). It is demonstrated that the proposed models predict the R-value and resilient modulus values close to the laboratory measured values for all studied soil types.