Performance of lime-metakaolin pastes using gravel wash mud (GWM)

The performance of ternary binders using lime, metakaolin (MK) and gravel wash mud (GWM) powders is studied for the development of novel lime-pozzolan pastes. This study examines the influence of varying mixture proportions using different types and compositions of lime powders and GWM at different treatment levels on the mechanical properties of lime-MK-GWM pastes. Various characterisation techniques including particle size distribution (PSD), X-ray fluorescence (XRF), X-ray diffraction (XRD), compressive strength tests, simultaneous thermal analysis (STA) and scanning electron microscopy (SEM), were applied on the different raw materials, respectively, on the hardened pastes to determine the reaction kinetics, the resulting microstructure and the mechanical performances of the lime-MK-GWM binder systems. Higher strength-enhancing contributions of thermally treated GWM powders (calcined at 850°C) leading to compressive strengths up to 18 MPa were confirmed and the strength-based evaluations revealed that hydrated lime-based pastes achieved higher mechanical performances than hydraulic lime-based binder systems.