- Kamal Kishore Taparia, Vadraj Cement Ltd
What has been the demand growth for slag cement over the last two-three years, and how it is expected to pan out in the next three years?
The awareness about the superiority of slag cement in performance over other types of cements, especially in aggressive environments like coastal areas, marine works, effluent treatment plants, foundation works, and other similar structures is increasing amongst the engineers and the consultants.
The availability of slag cement in India is in to geographical areas, which are closer to integrated steel plants where granulated blast furnace is available as by-product. The production of slag cement is also dependent upon the availability of blast furnace slag, which in turn depends upon the production capacity of steel in India.
At present, the share of slag cement ranges between 8 to 10 per cent of the total cement consumption in India. It is expected to increase due to increase in acceptance of slag cement and also by the government approvals and specifications like Engineer's India Ltd, etc. during the next three years.
What is the demand-supply scenario of slag cement and what are the factors that will boost its demand?
At present, the slag cement, which is produced in India, is consumed without any difficulty. The share of slag cement can be increased provided adequate quantity of blast furnace slag is available for production of slag cement. It may be interesting to note that during the production of PPC cement only 25 per cent of the total production of fly ash is consumed by the cement industry in India, while 100 per cent slag from steel plants is utilised by the industry to produce slag cement.
There is distinct preference for slag cement amongst engineers, consultants and consumers for PSC over PPC.
The following factors are likely to boost the demand of slag cement:
a)Aggressive conditions, i.e., sulphate, chloride attack from soil and polluted water and alkalis coming from aggregates in many part of the country. Best example is new green field project of petroleum refinery by HPCL coming up at Barmer-Rajasthan where slag cement is specified.
b)Easy availability in all geographical areas in the country.
c)Awareness about the advantages of slag cement over other types of cement especially in aggressive environmental conditions.
d)Consideration of long term strength and durability of structures over the initial strength alone.
e)Increased production of steel in the country and availability of blast furnace slag.
Please enumerate technical and environmental advantages of slag cement and areas of its utility?
Slag cement has distinct advantages over other types of cement in the following quality parameters:
a)To make concrete more impermeable to ingress of the harmful liquids and solids.
b)To enhance the durability of concrete by rendering its micro structure denser and cohesive.
c)To develop stronger bond with steel over the period and to resist cracking in concrete.
d)To develop higher long term compressive and tensile strength in concrete.
e)The cohesiveness of concrete mix using slag makes it easy to pump, place, compact and finish as compared to concretes using other types of cement.
f)The concrete using slag cement are lighter in colour and reflect more light and avoids rise in temperature especially in urban areas.
g)Concrete with slag cement is aesthetically more pleasing.
h)Slag cement can utilise blast furnace slag up to 70 per cent while PPC can use fly ash only up to 35 per cent as per the Indian Standards. Thus, slag cement is more environmental friendly than PPC and other types of cement.
Areas of application:
a)Slag cement can be used for all types of civil engineering works as per the IS - 455 of 2015 standards.
b)Slag cement is very beneficial in coastal and marine environments.
c)Advantages in construction of effluent treatment plants, water and sewage disposal works.
d)All foundation works, basement and underground structures.
e)Irrigation works, dams, canal lining and river training works.
f)Bridges, metro rails, highways, ports and other infrastructure works.
What is the supply situation of raw materials for slag cement, particularly availability of slag?
The availability of slag is limited in India as the slag produced by the integrated steel plants through blast furnace route is only utilised for production of slag cement. It is estimated that nearly 15 to 18 million tonnes of slag is produced per annum by steel plants in India.
The entire quantity of blast furnace plant is utilised by the cement industry in production of slag cement. The same situation is likely to continue as the growth of cement industry is more than the growth of steel industry.
What are the cost and price trends of slag cement when compared to OPC?
The cost of slag cement ideally should be more than OPC due to its numerous advantages. In most of the Eastern markets, the slag cement is sold at premium. PPC pricing is generally lower by a few rupees a bag as compared to OPC. The advantages of slag cement over PPC are now recognised, and in most of the markets, slag cement commands a better price than PPC.
Do you have expansion plans on the anvil and what is the usual gestation for setting up a slag cement plant?
We do have the plan for expansion to produce more quantity of slag cement. However, as mentioned earlier, it depends upon the availability of blast furnace slag. In a way, it is related to the expansion of the source of blast furnace slag. The gestation period in setting up a new cement unit is about two years.