Experimental study of the effects of curing time on geotechnical properties of stabilized clay with lime and geogrid

Lime treatment is extensively used to improve the properties of soft and weak soils. One of the most important reasons for using lime is to reduce the swelling behaviour of the clay soil. The reaction of quicklime (CaO) with water, forms hydrated (slaked) lime (Ca(OH)2) and therefore properties of clay are improved by the creation of extra bonds. Increasing the brittleness of lime stabilised clay is the major shortcoming of using lime. Therefore, the aim of this study is to investigate the effects of curing time on geotechnical properties of stabilised kaolinitic clay with lime and geogrids. At first, different percentages of lime (3, 5, 8%) were mixed with the soil to study unconfined compressive strength (UCS), secant modulus (Es), failure strain (εf), deformability indexes (ID), brittleness index (IB), bulk modulus (K), shear modulus (G) and resilient modulus (Mr) of specimens using unconfined compression test after different curing times (i.e. 7 and 28 days). Moreover, to alleviate the brittleness, geogrid was added to the lime-stabilised-clay in four layers at constant intervals and the geotechnical properties were also observed after the curing times. Based on the results the geotechnical properties of clay were improved significantly by adding lime and geogrid, however, by increasing the percentages of lime, the brittleness index increased and the deformability index decreased. According to SEM test, the addition of lime reduced voids and therefore improved the geotechnical properties of the soil. A phenomenological model was used based on the test results to develop the equations for predicting the properties. The results showed that there was a good correlation between the estimated values given by the predicted equations and the measured values.