How green are cement, steel and bricks ?

I saw this query on an Internet group a while back and felt it was important to pen down my thoughts on this. I have been talking about this for a while now, but never got down to writing about it. So here goes.

Cement, steel and the standardised burnt clay brick

To arrive at a better understanding on how green these materials are, one would have to address this from different perspectives:

• From an embodied energy perspective
• From a scale of consumption perspective.
• From a regional impact perspective
• From a construction vs livelihood perspective

Embodied Energy

An IGH Projection

Cement and steel are processed materials, that consume a lot of energy in their making. Modern day Cement mainly is a mixture of various components, essentially lime, and other binders.
Cement from the time of the Romans, has been a binder material used for making building components adhere to another. Lime was an crucial part of this mix. Other pozzolanic materials like volcanic ash, etc were also added by other groups.  In pre-industrial times, the production of cement did not involve much more than animal driven and human labour.... from the extraction of raw materials right down to the production of the cementitious mix. Today of course, cement production involves the use of generated energy (driven by electricity, diesel, coal, etc)
Steel in construction is an industrial era contribution (barring a few earlier usages), and has become a mainstay in all forms of construction. In the 5000 plus years of civilisation history, it is interesting to see that a material that was never ever used in construction , has become an integral component of all construction in just over a 150 years (not that this bad in itself)..

A projection by IGH

Burnt Brick production has remained the same over the past many centuries, but the standardisation since the British times has seen an inefficiency in the burning process. In earlier times, bricks came in all sizes and shapes primarily due to the differences in clay compositions between regions, resulted in better burning. Today, the standard burnt clay brick is 9" x 4.5" x 3", all over the country.

A great amount of energy goes into the manufacture of modern day cement, bricks and steel .There is a dearth of consistent data on the applicable embodied energy for these materials, primarily due to the varying conditions of production, sources of energy and scales of operations. However, if one does consider the potential contribution to CO2 emissions by these materials used today, the significance is apparent. On average a 1000 sft residential unit (independent house or apartment) would result in the emission of anywhere between 45 to 72 MT of CO2 into our atmosphere. In the context of over a 100 1-million plus population cities in India alone, and with an ever burgeoning urban population this is significant.

Consumption

A file picture of iron ore mining activity in Bellary, Karnataka.
Photo: M. Ahiraj, The Hindu

What is even more significant is the rate of production of these materials in the last 100 years (post the industrial revolution). The modern global economy has created a mad rush to urbanise and has pushed rural populations to cities in search of greener pastures. The combined effect of Business, Growth and Migration has led to a boom in construction activity for business, residences and infrastructure to support this. The rate of consumption is fed by a hitherto unseen rate of extraction of raw materials and production of construction materials and components.
This consumption has great side effects. Beyond the CO2 emissions, up-the-chain environmental damage due to pollution, afforestation, and harm to ground water is grave and has resulted in changing the surface of our planet like never before. Transport of these materials has meant the creation of further construction corridors and which has led to massive atmospheric pollution due to petroleum exhaust (incidentally, never before has petroleum been burnt in such a scale as in this period). The large scale construction activities that we see in our cities and towns today create dust and air-pollution, causing health hazards like never before.

Regional impacts
Change is inevitable, but it is the nature of change that has to be examined. There has been tremendous and rapid transformation in the way we build, originally from a construction material/system point and eventually in the forms that the architecture has taken. This change is more of an imposed change, fuelled by industry set up in independent India and also by the great aspirations of the Indian masses. Agendas set by early politicians and subsequent governments further added to the modernisation of India. This trickled down to built form, but has resulted in a complete alienation (and extinction in many cases) of building traditions and regional architecture. Cement, steel and the modern day brick rode this wave of change. RCC, cement and 'sariya' (reinforcement steel) are now household words, and almost every contractor and mason knows how to work with these materials (at least has a working knowledge). These materials are now unshakeable and integral components of construction in urban India. They are considered as the solution to all evils of what is perceived of as 'kucha' works. So deep is the knowledge loss that current day construction workers hesitate (and refuse) to apply traditional materials and systems that were prevalent only half a century ago..

Construction labour at a site

A disappointing outcome of the latter half of the 20th century in India is the emergence of a monoculture in architectural form that has taken over its urbanity. While nationhood united diverse people and cultures, the direction construction has taken ever since is leading to the wiping out of this very essence of diversity. What is more ironic is that numerous studies done over the past couple of decades have shown the limitations and inability of this architecture/built form in providing appropriate occupant thermal comfort, colour and character, and so on. Yet we persist. While change that is inherent (or from within) is understandable, un-reined change with no care for the consequences is not.

Construction vs livelihood
Resources followed the money. Skill-sets needed for RCC construction were simple and were honed, whereas traditional building know-how became unviable over the years. Industry supplied cement, steel and the standardised burnt-clay brick to every nook of this country, while traditional skills were limited to small regional (maybe even sub-regional) extents. Therefore, a moving populace (mostly rural folk looking for better incomes) picked up what would earn them an income irrespective of where they locate to, and moreover there was a lot of jobs for the picking. This scenario is still unfolding, killing our building traditions steadily.

We see that this illustrious group of modern day materials (cement, steel and the standardised burnt brick) has a high embodied energy, cause immense environmental damage (both up and downstream), has altered the regional diversity of our building traditions and systems, and is continuing to wipe out the livelihoods of traditional crafts persons. The 'Business As Usual' scenario of modern day construction materials and systems  is unsustainable and needs an overhaul. Alternatives to these materials and construction systems are urgently necessary in the context of the ecological tilts that such human activity has caused over the last century and a half. Small gestures of reducing a bit of this or that is not going to add up as anything significant. The time for a complete re-think to redeem ourselves is now.