Stress-Strain-Strength Behavior of Lime-Stabilized Soils during Accelerated Curing

Given the schedule pressure of lime-stabilized soil construction, many agencies specify the use of elevated temperature (e.g., 41°C), shorter duration (e.g., 5–7 days) accelerated specimen curing for unconfined compressive strength (qu) testing and acceptance as a proxy for qu of specimens normally cured under 28-day 23°C conditions. Moreover, lime and highway transportation industry associations prescribe a unique accelerated curing regime for all lime-stabilized soils (7-day, 41°C). This paper presents the results from a laboratory investigation of stress-strain-strength development of four lime-stabilized soils under 2–8 day 41°C accelerated curing and the 0–28 day 23°C normal curing regime. Specimens cured at 41°C reached qu values equivalent to 28-day 23°C qu after 1.8–5.9 days. Accordingly, 7-day 41°C curing overestimates 28-day normal cure qu by 13–260%. When combined with a detailed analysis of data available in the literature, the results illustrate that the prescription of a unique equivalent accelerated curing regime is oversimplified and can lead to significant overestimation of design qu.