Physical properties of cold process cement

Abstract

Cold process cement is a mixture of pozzolana and activator. Calcination of raw materials is not required in manufacturing process, thus burning of fossil fuel is avoided. Different chemicals are used to activate the pozzolanic materials. In this work cold process cement was prepared by activating the ground granulated blast furnace slag of Rourkela Steel Plant (RSP) with alkali activator lime and sulphate activator plaster of Paris. Lime content in the raw mixture was varied as 5, 10, 15, 20, 30 and 40% and the plaster of Paris as 1, 1.5, 2, 2.5, 5 and 10% of the dry weight of slag. The consistency, setting times (initial and final) and soundness of mixes were determined and reported. Borax is used as a retarder of setting time. The initial and final setting times of the mixes are found to be lesser than the value prescribed for ordinary Portland cement (OPC). An addition of borax retards the setting time and a borax content of 0.4% by mass gives the setting times that is normally prescribed for OPC. Soundness of this binder varies between 1mm to 3 mm satisfying the prescribed limits. In brief the nature and dosages of activator play a crucial role in setting and hardening process of the mixture and the physical parameters prescribed for OPC can be achieved by proper proportioning of raw material compositions.