Portland Slag Cement (PSC) (BIS CERTIFICATION AS PER IS:455) is manufactured by inter-grinding Granulated Slag, Portland cement clinker, and Gypsum. However, it can also be manufactured by mixing Ground Granulated Blast Furnace Slag (GGBS) with Ordinary Portland Cement (OPC) in the blender. As per IS:455, the granulated slag constituent shall not be less than 25% and not more than 75% by mass of Portland slag cement. However, in India, about 45%-50% slag, 3%-5% gypsum, and 45%- 50% clinker are used normally for manufacturing PSC.
PSC is an eco-friendly product because of the usage of slag while manufacturing this cement. Slag is a by-product of iron/steel and hot metal which is generated during the manufacture of iron/steel or hot metal. It provides better resistance to alkali-silica reaction. Not only that, PSC has a good compatibility with all kinds of admixtures. PSC is preferred in mass construction because of its low heat of hydration. Due to its flexural strength, PSC is used in infrastructure projects too. As mentioned in IS:456 – 2000 version, PSC exhibits better sulphate resisting properties when more than 50% slag is used. As corroborated by different technical articles, when it comes to durability, PSC is the most preferred cement for concrete constructions.
Portland Pozzolana Cement (BIS CERTIFICATION AS PER IS:1489 Part-I) is a fly-ash based blended cement. High-quality Portland cement clinker, gypsum and pozzolanic materials are thoroughly inter-ground or blended in certain proportions for producing PPC. Pozzolanic materials include fly-ash, shale, volcanic ash, calcined clay, silica fumes etc. As per IS:1489 (Part 1), the Fly-ash constituent shall not be less than 15% and not more than 35% by mass of Portland Pozzolana Cement. PPC is an eco-friendly product as it is manufactured using fly-ash, a by-product from the thermal power plants. It provides better resistance to alkali-silica reaction. Not only that, PPC has a good compatibility with all kinds of admixtures. PPC is preferred in mass construction because of its low heat of hydration. Due to its flexural strength, PPC is used in infrastructure projects too. As mentioned in IS:456 – 2000 version, PPC also exhibits better sulphate resisting properties. As corroborated by different technical articles, when it comes to durability, PPC is referred to as one of the most preferred cement for concrete constructions.
Ordinary Portland Cement (BIS CERTIFICATION FOR 33, 43 & 53 Grade AS PER IS: 269-2015) is the most commonly used type of Portland Cement. OPC is a mixture of calcium carbonate, silica, iron, and alumina. Limestone (calcium carbonate) is heated in a kiln with other components. Once it hardens and turns into “clinker”, it is finely ground with a small amount of gypsum mixed with it to produce Ordinary Portland Cement. It is mainly used for general construction where it isn’t exposed to sulphates found in groundwater or the soil.