Utilisation of lime activated GGBS to reduce the deleterious effect of flooding on stabilised road structural materials: A laboratory simulation

Reducing the high embankments associated with road construction especially in low-land areas to within the design flood level, will offer project overall cost reduction amidst enhancing environmental friendliness. This is necessary to mitigate the global environmental concerns of flooding envisaged to be more critical in low-land areas and to keep up with the pressure exacted on land due to road infrastructural development projects, it is important therefore to develop more sustainable technologies. The utilisation of marginal, waste and/or by-product materials such as Ground Granulated Blastfurnace Slag (GGBS) to modify the engineering properties of locally available geomaterials such as local soils could be handy. Laboratory tests such as Unconfined Compressive and linear expansion tests were carried out to simulate the effects of flooding on the road layers in terms of strength and durability, against existing design criteria for submerged materials. Cylindrical test specimens of 50 mm in diameter and 100 mm in length were produced from Lower Oxford Clay stabilised with lime–GGBS stabiliser materials. Linear expansion tests were conducted and an alternative durability testing regime of soaking in water was also followed. The results obtained demonstrate that with careful selection and research, the local materials are capable of achieving structurally sound and environmentally friendly properties for durability comparable to, and sometimes better than, materials formulated using the more expensive and increasingly unsustainable traditional stabilisers such as Portland Cement (PC) or even lime. These suggest viability and feasibility of enormous savings as more marginal materials are used to replace virgin and classical material.

► Lime content for optimal stabilisation of Lower Oxford Clay is about 6%.
► Lime-activated blastfurnace slag is a better binder for clay than lime or cement-activated slag.
► Blastfurnace slag requires only small quantities of lime for activation to stabilise clay.
► Lime-slag bound clay is durable enough for applications in road embankments in flood-prone areas.