Limed clay as a replacement for construction sands

In Belgium, more particularly in Flanders the soil contains of lot of clay, sometimes in combination with loam and/or sand. Due to the limited bearing capacity of clay soils, these soils are not very well suited to be used for foundations of buildings and infrastructure. To improve the properties of clay soils, stabilization with quicklime is often used. This technique was first introduced in the sixties during the construction of highways. The annual use of lime for soil stabilization keeps increasing. In 2012 approximately 1.6 million tons of soil was treated that way. History shows that the lifespan of most buildings and infrastructure is about fifty years. The excavation of clay soils treated with lime will significantly increase in coming years. Flanders is a region with limited availability of natural resources. The Flemish Government stimulates the use of secondary resources to relieve the pressure on natural resources. Excavated clay soil treated with lime can replace natural sand in some applications. This paper presents the results of an investigation on the possibility of replacing sand in construction application by excavated clay soils treated with lime. In the first part properties of normal clay particles are compared with those of limed clay particles. Test results show a significant increase of sand equivalent value and a decrease of methylene blue value. In the second part of the study cement was added to different mixtures as a hydraulic binder. These mixtures were tested on their mechanical properties, such as California Bearing Ratio and compressive strength. The strength development of these mixtures is similar to that of equivalent sand-cement mixtures.status: publishe