Gone are the days when concrete was considered being drab and dull. The new trends in concrete, has enabled the product look attractive and has reduced the number of days required for the projects. Narendra Patel, Chairperson, Indian Concrete Institute, Maharashtra, Mumbai Centre talks about the ongoing trends in the concrete industry, current situation and the challenges.
A country’s progress is measured by the cement used. In countries like China, cement used is 154 kg per person and India lies way behind utilising only 54 kg per person. So we can see how much more development in India is to come. And if the cement industry progresses it is quite obvious the concrete industry will rise. However, both cement and concrete industry have been growing rapidly.
Concrete as a product today has many types, which enables the engineers to reduce the number of days required for the project.
Latest trends in concrete industry Perforated concrete
It rains a little and the streets roads get water logged. For combating this situation, we use perforated concrete, which allows water to seep in so that the roads are not water logged. This concrete is also used for rain water harvesting since it absorbs water and gets drained off easily thus reducing risk of flooding. Many projects have been built using perforated concrete. Mostly this concrete is used in the buildings and new constructions today, due to utilisation for rain water harvesting. We had used perforated concrete in Gujarat for getting fresh water from the dams to the wells. By using this concrete one can save water and the problem of flooding also will be solved. This technology is used on the sports pitches.
Transparent/ translucent concrete: Another form of concrete which has become popular is transparent or translucent concrete. This concrete is used on the walls and one can see the shadows and movements beyond the wall. Translucent concrete is a combination of optical fibers and fine concrete. Thousands of fibers run side by side transmitting light between the two surfaces of each element. Because of their small size the fibers blend into concrete becoming a component of the material like small pieces of ballast. In this manner, the result is not only having the two materials mixed- glass in concrete- but a third, new material, which is homogeneous in its inner structure and on its main surfaces as well. The blocks are load-bearing and provide the same effect with both natural and artificial light. Glass fibers lead light by points between the wall-surfaces. Shadows on the lighter side will appear with sharp outlines on the darker one. Even the colours remain the same! Such a wall with glass fiber-pixels acts as if scanner and screen are united. This special effect creates the general impression that thickness and weight of this concrete wall disappear and concrete becomes live.
Precast concrete
Normally when we build any road or bridge, a lot of time is wasted and also causes traffic jams. Now when we use precast concrete, the beams and girders are and assembled in the factory itself and then are erected on the site after mid night and early morning hours to avoid traffic problem. Recently in Mumbai there were around 50 flyovers built but no one saw how they were built since precast technology was used. Using this concrete allows cost cutting, saves time, does not hamper traffic, accuracy and quality is maintained. Similar method was used when we made a guard stations and housing between the borders of India and Pakistan in Gujarat about 1000 km spread
Slip form
Slip form is normally used for shuttering. For e.g. if 200 ft chimney is to be built then you need to take the operations only up to four feet and the same process had to be repeated for 50 times. Each operation would take three to four days. Instead of this repetition we have now started using slip form of concrete wherein we install these sliding shutters which can be slide the very next day. Thus the project which would have taken 200 days to finish ends in around 30-35 days. Slip form of concrete is used in many other form of structures like silos, water towers etc.
Shot concrete
This form of concrete is used while repairing of the building. Whenever a structure has become weak, we provide force so that the concrete has original strength. Mostly it is used when the concrete is weak.
Dyed concrete
Dyed concrete is coloured concrete that looks very attractive due to an appealing appearance. The designs are made after the concrete is dried. this concrete is very useful in the factories since there are various pipelines for water, cables etc. If during construction the water pipe line needs to be worked on and the patch is coloured in blue, so only that part of the blue patch will be dug. This will prevent the other lines from getting disturbed. Or there are times that when we open other lines, the chances of damage are quiet high. So this concrete is very appealing and very useful.
Lightweight concrete
Lightweight concretes can either be lightweight aggregate concrete, foamed concrete or autoclaved aerated concrete (AAC). Such lightweight concrete blocks are often used in house construction. This type of concrete is light and reduces the pressure on the foundation of the building. For e.g. if the builder wants to add a couple of floors on an eight storey building, then light weight concrete will be used. There is hardly a difference of 5-10 per cent and durability is ensured. Foamed concrete is a highly workable, low-density material which can incorporate up to 50 per cent entrained air. It is generally self-leveling, self-compacting and may be pumped. Foamed concrete is ideal for filling redundant voids such as disused fuel tanks, sewer systems, pipelines, and culverts – particularly where access is difficult. It is a recognised medium for the reinstatement of temporary road trenches. Good thermal insulation properties make foamed concrete also suitable for sub-screeds and filling under-floor voids.
Autoclaved aerated concrete (AAC)
AAC was first commercially produced in 1923. Since then, AAC construction systems such as masonry units, reinforced floor/roof and wall panels and lintels have been used on all continents and every climatic condition and can also be sawn by hand, sculpted.
Challenges
The cement and concrete industry is growing rapidly, however we come across major challenges. One of the biggest challenges we face is the lack of support from the government, since the implementation of policies has been slow. The moment the government speeds up the process of implementation the strategies, the progress of the industry will be doubled.