Potential of Limestone Calcined Clay Cement (LC3) in soil stabilization for application in roads and pavements construction
Loyford Muchui Mugambi, Sandra Mujombi, Victor Kiptoo Mutai, Julius Toeri, Joseph Mwiti Marangu, Luca Valentini
Abstract
Clay soil is associated with geotechnical problems of swelling and shrinkage, which causes deformations on structures. Ordinary Portland Cement (OPC) which is the most common stabilizing agent for clay soils, remains unaffordable in most developing countries, and its production also contributes about 8 % of global anthropogenic CO 2 emissions. The present study aimed to investigate the effect of Limestone Calcined Clay Cement (LC 3 ) on the stabilization of clay soils for applications in road construction. Clay soil was mixed with quarry dust to reduce the clay content and save cement. The mixture was stabilized using LC 3 and OPC separately in proportions of 1 %, 3 % and 5 %. The effect of stabilizer dosage on the performance of clay soil was studied by monitoring the changes in Atterberg limits, Proctor test and soaked California Bearing Ratio (CBR). The mineralogical and microstructural investigation was carried out using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). Plasticity index (PI), linear shrinkage (LS), and optimal moisture content (OMC) of stabilized soil was found to decrease with increase in the dosage of LC 3 and OPC. The Maximum Dry Density (MDD) and soaked CBR increased with addition of both LC 3 and OPC. Formation of calcium silicate hydrate (C-S-H) in both LC 3 and OPC stabilized clay soil, as well as formation of Hemi-carboaluminate in LC 3 stabilized clay soil was responsible for improved properties of the stabilized soil. The performance of LC 3 was found to be comparable to that of OPC, at optimum cement ratio of 5 %.