Strength and Micro Observations on a Lime Treated Silty Soil

A large laboratory research project founded, by the European Community and involving Academies and Industry has been carried out to fill the gap between the empirical design rules of soil treatment by lime and the mechanistic design approach used for transportation infrastructures. This required a multidisciplinary approach both at macro/micro-scales, using common geomechanical test methods, microscope observations and micro scale tests. These tests were performed on samples of a silty soil that had been treated with respectively 1.5, 3 and 4.5 % calcic quicklime. The curing conditions were chosen as main parameters for the testing program, viz. time (up to 730 days) and temperature (20, 36 and 50 °C). Due to a lack of space, only results with samples cured at 20°C are presented in this paper. All evolutions of the mechanical parameters were coupled to the micro-scale test results. The aim of this analysis was to gain a better insight in the relation between strength macro-scale parameters and micro-scale reactions such as the development of CSH and CAH during pozzolanic reactions.