Effect of curing regime on the bearing capacity of soil stabilized with class F fly ash and cement

Abstract

The California Bearing Ratio (CBR) defines the behaviour of road sub-base and granular base for flexible pavement. In conventional CBR test, compacted sample are lefted in air for 24 hours and 4 days in water. These times are not enough for pozzolanic reaction stabilization the time period is enough for first solidification but not enough for the final strength. Hence the values of CBR test do not present actual in-situ soil strength parameters. In this study the effect of soil stabilisation, using Class F fly ash and cement, on the CBR value of fresh and 28-day-old samples was examined. Two soil matrices were used-Bilecik clay and lime were used asonea matrix and another matrix was made of Bilecik clay, bentonite and lime. Fly ash and cement were used as additives. Wet CBR test was performed on mixtures and quantity of swelling and CBR values were measured. According to these results bearing ratio of 28-day cured mixtures and treated fly ash are higher by 4%-160% than the results of conventional CBR tests. Under the same circumstances most bearing ratios of cement treated soils decreased by approximately 50%. According to these results, for soil stabilised using a pozzolanic reaction the CBR test should be performed on 28-day cured samples.