Do you still see a preference for OPC in certain segments of the cement market such as institutional or in certain geographies? How do you deal with these national preferences?
Yes. OPC cement commands preference in certain geographic markets and institutional segment in comparison to trade segment. This preference is predominantly in institutional segment due to faster setting time and better compressive strength over PPC/PSC cement. OPC Grade 43 / 53 are more preferred in infrastructure projects and have emerged as the top choice of engineers and engineering companies engaged in construction of mega projects – such as national highways, bridges, transmission lines, power plants, industrial and residential structures. Also in major infrastructure projects OPC Grade 43 / 53 is approved through central/State Government/local governing bodies/institutions over PPC/PSC, making OPC preferred product in institutional segment.
Another reason why OPC is preferred over PPC / PSC is because in certain geographies or markets availability/supply of fly ash and slag is a constraint due to location of power and steel plant because of which supply of PPC/PSC cement is very limited hence people go for OPC cement more. Some of its properties like higher strength and faster setting the consumers consider that OPC cement is better over PPC and PSC.
What is your company’s overall product mix – OPC, PPC and PSC? To what extent is this mix is influenced by market preferences and to what extent by availability of fly ash and/or slag?
At Nuvoco, we are committed to sustainability and hence our product mix is skewed towards PPC and PSC cement than OPC. The product mix is primarily based on the preferences of the consumer as well as geographic locations. In certain market consumer preferences are driven by color of cement thought it does not have an impact on its properties. In some markets consumers prefer to use darker cement i.e. PPC while in other market they opt for PSC cement as it is lighter in shade. Whereas in certain market consumer prefer OPC cement. Simultaneously, the customer prefer to go with a particular type of cement be it OPC, PSC or PPC based on the supply / availability in that particular market because if the customer is building his own house then he would not like to wait for a particular type thereby increasing the wait time.
Availability of fly ash and slag is another factor, which affects the availability of various cement grades. Basis the location of steel and power plants, fly ash and slag is available. Not only this cement plants should also be strategically located so that both these materials are readily available to manufacture PPC and PSC cement. To overcome this hurdle many cement companies are entering into long term supply agreement with various steel and power plants to get an uninterrupted supply of these raw materials.
How do you view the historical growth rates of PSC & PPC in your markets? How do you project this growth in coming five years?
Historically ever since government allowed blending of cement with OPC there has been continuous growth in the sales of PSC / PPC cement. There has been a very good penetration of blended cements in the market. Earlier OPC used to be the market leader in India. However, today, it represents only about 20-25 per cent of the market share. In this context, it is encouraging to note that nearly 75 per cent of cement production in India at present is in the form of blended cement of various types, as against only 30 per cent in 1999-2000. We are committed towards the preservation of natural resources and in that context we have put major thrust on using blended cements like PPC and PSC.
In order to promote a sustainable future, cement companies should pass on cost benefits and the government must provide incentives along with compulsory use of blended cement in all government projects. Since blended cement uses factory waste, a by-product, as its raw material, it is important for environmental reasons that we maximize the use of PPC / PSC and move towards a greener path.
Major companies are migrating from traditional OPC (approximately 95 per cent clinker) towards alternative types of cements such as fly ash based (approximately 75 per cent clinker) or recently growing composite cement which is a mixture of slag as well as fly ash (approximately 65 to 70 per cent clinker) thus not only reducing the carbon emission due to manufacturing process of clinker but also using materials, which were earlier disposed from carbon intensive sectors like power and steel. With the growing awareness towards environmental issues and the internal target of large cement manufacturers to increase the share of alternative fuels, the share of alternative fuels would increase to around 10 per cent and contribution from traditional fuels is going down.
What are the applications or regions where you would recommend use of PPC/PSC to your customers and why?
Selection of a particular grade of cement is almost always based on the type of concrete, which will be used for construction so as to ensure durability of the structure. Thus, making wise choice of cement type for particular construction site prevents structure from deteriorating and saves much repair and rehabilitation cost later.
PSC and PPC cement is suitable for high rainfall areas and coastal areas as these offer higher longevity of structures. As PSC / PPC are left with very little lime after complete hydration reaction they offer highest resistance against sulphate and chloride attacks and environmental pollutants.
Applications of Portland Slag Cement (PSC) – It is OPC + granulated slag cement. It gives low heat of hydration. The slag should be more than 50 per cent and up to 70 per cent. It is used for:
Marine and off shore structures – very high chloride and sulphate resistant.
Sewage disposal treatments works
Water treatment plants
Constructions which are expected to be attacked by dissolved chlorides and sulphate ions.
Should be mainly used for all future structures.
Applications of Portland Pozzolana Cement (PPC) – It gives low heat of hydration and reduces the leaching of calcium hydroxide. Thereby PPC is prone to fewer cracks and reduced shrinkage, better workability and finishing (as fly ash based cement are spherical in shape and finer in size). It is used for:
Hydraulic structures – dams, retaining walls
Marine structures
Mass concrete works – like bridge footings
Under aggressive conditions
Masonry mortar and plastering
We have heard a lot about peculiar customer perceptions about colour and smell of cement in some markets? Have you experienced this phenomenon? Are these related to presence of slag/fly ash in cement? How do you deal with such idiosyncratic ideas?
Yes, customers in different geographies of our country have peculiar understanding towards the colour and smell of cement, however both has nothing to do with the quality of cement.
Colour of cement varies from dark to light due to the cementitous blends (fly ash / slag). Fly ash – a by-product from thermal power plant is used in producing PPC. This fly ash consists of traces of unburnt carbon and other impurities hence PPC is darker in colour. GGBS (Ground Granulated Blast furnace Slag) is off white in colour, which is used in producing PSC. Hence the colour of PSC is lighter. In certain geography lighter colour has advantages as darker colour and vice versa.
The colour of PPC containing fly ash as pozzolana will invariably be of slightly different colour than that of OPC, depending on the colour of the pozzolonic fly ash that is used in the manufacture. However, the colour of cement, whether it is PPC / PSC or be any other grade, has no relationship with the quality of cement. The colour of the cement is gauged by its C4AF content and the pozzolonic material used. The higher the C4AF the darker the cement will be. Similarly, the lighter the colour of pozzolonic material, the lighter the shade of the cement. As such, there is no governing specification for the colour of cement. One cannot gauge the quality of cement by looking at its colour. The quality of cement can be assessed only by testing its physical and chemical properties.
Traditionally basis availability of PPC / PSC cement and its usage, end user/mason/engineers have developed the perception that cement quality is dependent upon colour which is a myth. Basis our PPC / PSC product availability in different market, we conduct lots of customer engagement programmes, mason/engineers/architect meets to create awareness on the quality of product. We provide sampling at customer site and after sales service to resolve complains (if any). Our innovative product are tested at our research centre, i.e., CIDC and we provide customer with our quality test reports to convince them on the quality of cement.
Recently BIS have permitted composite cements to be manufactured and sold in India. What is your strategy for introducing this product in the market and what are the manufacturing and marketing challenges involved in this?
Composite cement is covered under IS: 16415-2015 and is best suited cement to produce high strength concrete, which is highly durable. Composite cement is a mixture of high quality clinker, fly ash, granulated slag and gypsum.
Composite cement offers better opportunity to conserve natural resources in terms of limestone by replacing higher percentage of clinker, having lower carbon footprint without compromising on concrete properties in green and hardened state. The finding of this study might be useful to accept composite cement for different concrete applications in construction.
Plants that are already making blended cements can easily and conveniently make composite cements. For example, those that are making PPC can add a hopper and feeder for limestone powder. Those that are making PPC can arrange to add slag, and vice versa. The proportions of the third component to be added, whether slag, fly ash or limestone, have to be decided in consultation with research institutes and in accordance with prevailing (or forthcoming) standards for composite cements.
The major challenge is making arrangements to store the different types of cement manufactured in a single plant. Configuration of mills making these cements and corresponding silos for storage would have to be worked out carefully, taking into account the volume and consistency of demand for each type of cement produced. For small and infrequent demands a multi-compartment silo could be used to store different types of cement. Again, factors like: dispatches by road and or rail and their respective volumes, dispatched in bag or in bulk would have to be taken into account in planning the overall layout of cement grinding, storage, and dispatch sections. Thus a layout would have to be worked out specifically for each plant to meet its requirements. These are the current challenges in aligning different activities for production of composite cement.
On marketing front awareness and acceptability with customer pose immediate challenges. However we understand these could be addressed by different activities we conduct to build the connection with our customers. Other challenge will be to get the product approved from different government agencies and passing the quality test.
The supply chain of both fly ash and slag has now become an integral part of cement manufacturer. In the light of this how do you see the current demand and supply scenarios of these two commodities. Fly ash and slag? What are the price movements of these two commodities? Are you recommending any regulatory help in ensuring more liberal supply of fly ash?
Coal/lignite based thermal power generation has been the backbone of power capacity addition in the country. Indian coal is of low grade with ash content of the order of 30-45 per cent in comparison to imported coals which have low ash content of the order of 10-15 per cent.
Several number of coal/lignite based thermal power plant is setup for providing electric to rapidly growing industrial as well as agriculture sectors. 70 percent of the electricity generated in India is from coal based thermal plant. The generation of coal fly ash is anticipated to increase for many more years, as a result of the increasing reliance on coal-fired power generation. Large quantity of ash is, thus being generated at coal/lignite based thermal power stations in the country, which not only requires large area of precious land for its disposal but is also one of the sources of pollution of both air and water. To reduce the problem caused by production of fly ash, it is now mandatory to use fly ash based products like cement.
Steel slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling. Virtually all steel is now made in integrated steel plants using a version of the basic oxygen process or in specialty steel plants (mini-mills) using an electric arc furnace process. The open hearth furnace process is no longer used. There has been continuous growth in steel industry due to increase demand in infrastructure development, real estate industry, etc.
With the increase in generation of by product from these industries, there dumping has always been an issue for these industries. Both by products are used in blending of cement to produce PPC and PSC cement. Logistics movement of both the by-product has been a challenge. Hence cement plant is ideally set up near to these industries. Logistics cost for movement of clinker is always lower compared to cost for movement of fly ash and slag. Cement industry go for a long term association with these industries for continuous supply of by-products.