A Shade of Grey…
Emon NC.
Without a whiff, in a slow and sublime manner, it has pervaded every aspect of existence.
Our homes, community, villages, cities and the planet that we occupy. Like the air that we breath, and the life that we lead, its presence is all encompassing and all-pervading touching upon every aspect of our day to day life.
It is a potent force that is constantly changing, evolving and molding the world around us. It is in front of our eyes, but we refuse to see it. We have touched it a million times, but we refuse to feel it. It has become us and we… Concrete?
By the time it takes to finish this sentence, the global building industry would pour more than 19,000 bathtubs of concrete. By the time one is halfway through this article, the volume would be the size of Albert Hall with spillover to nearby areas. In a day it would be almost the size of Chain’s Three Gorges Dam. In a single year, there would be enough concrete to cover a country like England.
The urban dwelling dreams of man is fueled by concrete. Its malleability, adaptability and endurance has made it the main force by which humans’ tame nature. Concrete is the core ingredient in our discourse of development. It is the silent strength, by which the veneer of this planet has been forever altered.
The tangible that surround us, in most part, has been made possible only by concrete. It is “almost anything” wrote architect Sara Nichols in her essay “almost anywhere”. Most of the buildings from skyscrapers to social housing are made of concrete. Even buildings made from steel, stone, brick or timber rest on concrete foundation.
Inside, concrete is ceilings and floors. Outside it is bridges and sidewalks, piers and parking lots, roads and tunnels and airport landing strip and subway systems. It is water pipes, sewers and storm drains. It is electricity: dams and power plants and foundation of wind turbines. It is politics: the wall between Israel and Palestine, the Berlin wall.
Born in the womb of the earth, it was discovered around 100 BC by the Romans from the volcanic ashes sticking to the slopes of Mount Vesuvius. It was mixed with lime and wetted to create cement. Roman concrete was used to build structures like the Pantheon and the Colosseum, parts of which still stand today.
There was a lull of about 1400 years before it was rediscovered in 19th-century France. But it was popularized by California based engineer Ernest Ransom. He poured concrete over iron and later steel to improve its tensile strength. Thus ushering in the marvel of “Reinforced concrete”
“By the time it takes to finish this sentence, the global building industry would pour more than 19,000 bathtubs of concrete. By the time one is halfway through this article, the volume would be the size of Albert Hall with spillover to nearby areas. In a day it would be almost the size of Chain’s Three Gorges Dam. In a single year, there would be enough concrete to cover a country like England. “
Reinforcement is the primary reason why concrete is everywhere today. Concrete has an extremely high compressive strength. It is really difficult to crush, but in hindsight, it is easy to pull apart. Iron and steel bars, however, possess the opposite quality. So rebar, become the commonly used method to create a strengthening skeleton for concrete to be poured around. Everything we see today is reinforced.
Concrete spells eternity went the popular discourse. The mythical power, permanence, and strength…its ability to protect us from dirt and danger still linger in the public imagination. A magic liquid rock that can be poured to create shapes and forms not possible with any other material. Stones take millions and millions of years to create, concrete can do it in a few hours. Mankind, it seemed has harnessed a geological force that is eternal…Its forever.
The problem however, is the process of carbonation, according to scientists. There is carbon dioxide everywhere in the air and any time concrete is exposed, carbon dioxide permeates its pores. It triggers chemical reaction and causes the rebar to rust. The iron thus expands, and the concrete develops cracks and fails.
The average age of a standard structure is calculated to be one hundred years. “When you consider that reinforced concrete was invented around hundred years ago” remarked an architect “You get this amazing image that the concrete all around the world is beginning to fail”
Humanity thus, has been depending on a material that had started to deteriorate from the moment it was first poured. While much of global south has embarked on a century of construction, global north faces a monumental challenge of maintenance, demolition and in worst case scenario, ruination.
We all seemed to be living within our own illusion and have choose to look the other away. We think we know where we stand with concrete or rather where we are going with it …The simple answer is nowhere
Legendary film maker Godard, in the opening sequence of the movie “Deux ou trios choses que je sais d”elle” shows a wheelbarrow caked in concrete amidst traffics and construction. Everywhere the camera looked, Paris was full of holes and crater, cranes filled the sky and tower blocks were portrayed as monuments of alienation and loneliness. Godard theorized that the city, like his female protagonist, has been forced to prostitute itself just to survive in an era of “progress”
But such monstrous scale of production has monstrous consequences. Concrete is like a time bomb in the human conquest of nature: redirecting great rivers, reducing quarried mountains to mere hills and contributing to biodiversity loss and mass flooding by sealing large swath of land in impermeable grey crust.
Concrete is now the second most consumed substance on earth after water. Thirty three billion tons of it are used each year. Beside, its production has also been a disaster for the atmosphere. The kilns used to heat limestone are commonly run on fossil fuel which produces green house gasses. Every kilogram of cement produces more than half a kilogram of CO2.
It has become a world of paradox. On one hand we have an impending disaster on the other we can’t just let go of it. It has been estimated that to keep up with global population, we need to build one Paris each week and one New York each month.
“To say we shouldn’t use concrete” said Karen Scrivener, a leading scientist engaged in creating low carbon concrete “is a meaningless comment because it is physically impossible to produce any other material in such large quantities”
The solution to this crisis won’t be a simple one. But a start can be made by acknowledging that there is a problem. Our amazement of the sky line of the magnificent cities, is to be matched by an understanding of the concrete that has gone into it.
Attempts are being made to develop low carbon concrete, encourage the use alternate material and source locally available building products. But looking into the immensity of the problem, it requires a coordinated effort of an equal scale. This is imperative if we wish to prevent our blue and green planet from turning grey.
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