Influence of mineral admixtures on strength and hydration products of lime-activated slag cement

The paper delineates the effect of mineral admixtures on the strength and hydration products of lime-activated slag cement. The slag cement was prepared by activating ground granulated blast-furnace slag with lime and plaster of Paris. The compressive strength of mortar specimens made with admixtures such as silica fume, fly ash, glass powder and ordinary Portland cement (OPC) in different proportions were compared with the control specimen at similar test conditions. X-ray diffraction, scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry and porosity tests were performed to examine the hydration products and/or the microstructure. A correlation was established between the developmental strength with the type of mineral admixture through analysis of the hydration products and microstructure. For the present test variables silica fume was found to be a better admixture compared to fly ash, glass powder and OPC.