The construction industry is always evolving with new techniques and methodologies. With the global industrial communities setting their sustainability goals for a better future, any new trends and technological advancements appearing within the construction industry must have a stronger focus on sustainability.
Er. G. H. Basavaraj, Managing Director, Chetana Engineering Services, Bangalore.
Reasons to look outside cement and steel in construction applications
India is the second-largest producer of cement and steel in the world. Production is driven by increasing demand in sectors such as housing, commercial, industrial construction and urban infrastructure development. According to the Indian Steel Association analysis report 2018, nearly 62% of the steel produced is used in the construction sector. In 2018, cement production capacity reached 502 Mt per year and is expected to grow rapidly to reach 550-600 Mt per year by 2025.
Production of cement and steel is mainly based on thermal energy from coal and other fossil fuels. Power and heat generation account for over two-thirds of coal consumption (three-quarters in terms of weight), followed by iron and steel production (almost 20%), cement (around 5%), and other industries like fertilisers, pulp and paper, non-ferrous metals and chemicals production. The cement sector’s share of total consumption of coal in its production will rise from 3% to 5% over the next two decades.
The data from many such studies and practical experiences show that the construction industry, at least in India, is very far from meeting the sustainability credits. In this regard, newer technologies have to evolve so as to motivate the civil engineering fraternity to deviate from the traditional concrete and steel construction system for the benefit of future generations.
Other than material consumption, the general trend of current construction practices also demands excess production and usage of concrete and steel. Few points of concern as seen in the construction practices are enlisted below:
- Fast-track mode of construction with greater dependency on cement composites.
- Delays and wastage of materials which is hindering productivity of the system.
- Quality control issues resulting in over consumption of concrete and steel
- Least scope for recycling options
- Labour oriented and time consuming.
Rising risk of overconsumption of limited raw material resources, very poor sustainability grades of construction materials, along with high skilled labour costs, and need for faster construction cycles have led to seeking other construction/ infrastructure alternatives. Given the concerns on the limitations of concrete-steel construction, Polymer Composite technology can be an alternative, under appropriate conditions.
Chetana-Polymer Composites (C-PC) building system is a novel approach wherein a combination of new composition of polymer composites and elements of building systems are integrated in order to meet the performance and stability requirements of any building.
In particular, C-PC relates to a combination of new recipe of filler based polymer composite and designing building elements such that all requirements of a building are met by the same composition. C-PC system is free from cement and steel but targeted to behave as a member/material equivalent to cement and steel composites used in construction applications.
C-PC Technology: Suitability & Performance
C-PC building system is a fly ash based polymer composite with different combinations of micro materials to create a robust particulate system held together by a superior polymer matrix. The production process is simple and less energy intensive with a greater scope for recyclability of ingredients then and there at the production facility. The schematic production workflow of C-PC building systems is shown in Figure 1.
Based on its Performance under loading C-PC is categorized into three basic grades.
Grade1 – 20 to 50MPa strength under compression, tension and flexure.
Grade 2 – 100 to 200MPa strength under compression, tension and flexure.
Grade 3 – 250 to 400MPa strength under compression, tension and flexure.
C-PC building system is advantageous over concrete and steel construction system when used in appropriate situations as per the performance requirements from different grades of C-PC. Few points of C-PC benefits over conventional construction practice are listed below and a brief comparison of C-PC with Steel/ GI system is given in Table 1.
- Factory made product; quality control with less manual labour.
- Carpenter friendly for customization.
- A more sustainable solution utilizing large quantity of industrial wastes and byproducts.
- Significantly reduced weight of structural elements.
- Automation friendly and advantageous for machines as in 3D printing.
Other Potential areas of C-PC applications in Construction and Infrastructure development can be briefly categorized as follows.
- Decking Sheets and Roofing sheets.
- Purlins, Angles and Channels.
- Single story portals, Interior use Columns, Light beams, Trusses, Rafters.
- Plain sheets for form works, partitions, suspended ceiling and water proofing.
- Designer Furniture and Staircase railings.
- Pavers, Fencing, Compound walls and Gates.
- Kerb stones and Traffic dividers for all roads.
- Electrical Power transmission and insulation accessories / fixtures.
With the availability of better sustainable options from Polymer technology, it becomes the responsibility of Civil Engineers and Material Scientists to develop alternatives to concrete and steel and identify its suitability for implementation on a vast scale. Such changes in construction and infrastructure materials and practice will not only save on over usage of cement and steel but also justifies the act of present day practice towards a more sustainable construction industry of future.