Behaviour of Moraine Soils Stabilised with OPC, GGBFS and Hydrated Lime

This paper aims to evaluate the effects of blended binders on the development of strength in moraine soils by optimising the proportion of several binders. We tested three types of soil as a mixture of moraine soils: A (sandy clay), B (clayey silt) and C (silty clay), collected in southern Sweden. The soil was compacted using a modified Proctor test using the standard SS-EN 13286-2:2010 to determine optimum moisture content. The particle size distribution was analysed to determine suitable binders. The specimens of types A, B and C, were treated by six different binders: ordinary Portland cement (OPC); hydrated lime (Ca(OH)2); ground granulated blast furnace slag (GGBFS) and their blends in various proportions. The strength gain in soil treated by binders was evaluated by the test for Unconfined Compressive Strength (UCS) against curing time. For soil type A, the strength increase is comparable for most of the binders, with the difference in behaviour in the UCS gain. The OPC/lime, GGBFS and hydrated lime showed a direct correlation, while OPC, OPC/GGBFS and GGBFS/hydrated lime – a quick gain in the UCS by day 28th. After that, the rate of growth decreased. Compared to soil type A, Ca(OH)2 performs better on the stabilisation of soil type B. Besides, the hydrated lime works better on the gain of the UCS compared to other binders. The GGBFS/Ca(OH)2 blend shows a notable effect on soil type A: the UCS of soil treated by Ca(OH)2 performs similarly to those treated by OPC with visible effects on day 90th. Cement and a blend of slag/hydrated lime demonstrated the best results for soil type B. An effective interaction was noted for the blends GGBFS and hydrated lime, which is reflected in the UCS development in soils type A and B. Blended binder GGBFS/hydrated lime performs better compared to single binders.