Evaluation of the modulus of subgrade reaction of a cement-treated base

<jats:p>The objective of this experiment was to (1) investigate the vertical pressures within a subgrade during plate load testing; (2) evaluate the sensitivity of the plate load test on stabilized base layers; and (3) generate field-measured effective 𝑘 curves to bridge the gap between stabilized and un-bound base course design processes. A total of 36 plate load tests were performed on three test sections of various subgrade strengths. Each test section included a cement-stabilized limestone base layer. The test sections and plate load testing were designed to obtain field-measured 𝑘-values on each lift of stabilized base and generate effective 𝑘 plots for stabilized limestone bases. The vertical stresses within the subgrade were measured during each plate load test. Results showed that when a 6 in. stabilized base is included, less than 20% of the surface pressure is applied 24 in. into the subgrade. Field-measured cement-stabilized effective 𝑘 curves were generated in this study.</jats:p>