Cement, Energy & Environment Jan-Mar 2002

The rigid pavement's requirement of natural materials like stone, sand etc. is 40 to 60 per cent of that required for flexible pavement. This means that saving of natural resources takes place if concrete pavements are adopted. It also means less problems for road builders in areas where stone is in short supply. Concrete roads use cement as a binder, which is a totally indigenous material unlike bitumen. Concrete pavements are also much more environment friendly. On the other hand bitumen is considered so polluting that the Supreme Court banned the operation of hot-mix bitumen plant in the Capital. Due to not requiring maintenance, cement concrete pavements are best for roads in urban congested areas where closing of roads for repair purposes is not feasible. In India cement concrete batch mix plants for RMC are already widely available, the expertise for construction of concrete roads has been gained in the recent past, and rigid pavements have proved to be a better option. The cost of the cement concrete can be further reduced substantially by use of fly ash and other suitable pozzolanic materials, such as blast furnace slag, as per the practice world over. Such usage also helps the environment by consuming polluting materials in large quantities. Cement concrete pavements offer better aesthetics, best drainage control, are amenable to extreme weather conditions, better reflect light at night and possess many other superior features. Precast cement concrete blocks in pedestrian side walks, petrol pump stations, garden paths etc. are in common use. Cement concrete can be used as overlay (white– topping) on existing bituminous roads requiring strengthening. The price of bitumen depends upon the price of crude oil fixed by OPEC without any relation to the normal escala tion . It also depends or the dollar-rupee exchange rate, which has been deteriorating almost continuously. The increase in oil prices has been over 20 per cent every year whereas the price of cement has remained almost static in the last 3- 4 years. The crude oil, which is presently available in India, has almost no bitumen content hence the present demand has to be met from imported crude oil. On the other hand installed capacity for production of cement is being used only 70 to 80 per cent, which ensures sufficient availability if used for the massive road construction programme ahead. The Government levies on cement accounts for 60 per cent of final cost whereas on bitumen it is 30 to 40 per cent. Hence the price of cement can be further brought down by rationalisation of levies which in tum shall make cement concrete roads more competitive. Courtesy:· International Workshop on Petcoke and Seminar On Energy and Environment in Cement Production and Sustainable Construction., 29 - 31 Jan. 2002 New Delhi, Seminar vol. Pp S IV 1 to 6. Email: nccbm @ giasdlol, vsnl. net. in. Web: www. cementresearch.com FINANCIAL HORIZONS Deutsci1e Bank Equity Research Construction output typically represents around H) per cent. of a country's GDP. However, countries with structural deficits in terms of infrastructure or housing can see this level rise to almost 20 per cent, while in mature economies it could stand below seven 65