What Is Concrete?


Let us get started by saying concrete is fantastic. We live our lives on top of it, in it and around it daily. On roads, walkways, in buildings and homes are where we find ourselves most of our days. Concrete has expanded human life literally in every direction. So much so that it is the most widely used man-made material in the world, averaging global production of over ten billion tons a year. If only the world could agree on important issues like we all agree on the usefulness of concrete! So why does the world love concrete so much?

In this article we will cover what concrete is composed of, and how it is made in its various forms. Applications for concrete and historical references will also be featured. If you are already looking to add this extremely versatile, durable material into your home improvement project, or if you are currently discovering your options, perhaps what you read below will bring you closer to a decision. Buddha Builders hopes to bring awareness to this incredible material so that you can get the most out of its use, no matter how big or small your project. Let’s get to it…

The Breakdown

Concrete is composed of three ingredients: aggregate, cement and water. Aggregate is usually medium or fine grade particulate material such as: sand, gravel, crushed stone and recycled concrete. As a component of the composite material concrete, aggregate acts as reinforcement, adding stability. On its own, it is often used as a foundation to strengthen roads and railroads. Aggregate is the most mined material in the world.

The second varying ingredient in concrete is cement. The word ‘concrete’ comes from the Latin word ‘Concretus’, which roughly translated means, appropriately, to ‘grow together’. Cement in its various forms brings the growth to the equation. Each type of cement has its own properties and advantages, but the most commonly used is Portland cement. Invented in 1824 by an English Stonemason named Joseph Aspdin, he named it after a quarry in the Isle of Portland that yielded strong stones. Portland cement is comprised of limestone and clay, and forms when the two are brought together at high temperatures and then ground. Essentially it is calcium, silica, aluminum and iron that come together in a chemical process to create cement. When manipulated in its process, the result is various forms of cement. Since we are talking concrete, for now let’s keep it simple and forgo diving into cement variation.

Speaking of diving, you really only want to do so into water, which is our third and final ingredient in concrete. Water works its magic by combining with cement, helping to create hydration reactions, binding the two substances to the aggregate in the mix. When water is added, that is when chemical reactions begin. This process occurs in three stages, and you can relate these stages to the range of hardness that are a result of mixing the three ingredients together. At first, concrete will be very malleable and easy to pour. Within hours it gains enough hardness to hold form, but overall the process continues and fully cures around 28 days after setting.

The background

The earliest concrete-like structures trace back to 6500 B.C. Advancements continued, including the creation and developed use of hydraulic lime, cement that hardens under water, which paved the way to the construction of underwater cisterns. Processes such as tamping were used, which create gel, the bonding agent formed in the chemical reactions that take place during hydration. Cement floors and rubble wall houses were built from the ground up. Fast forward to 3000 B.C. in Egypt, where the Great Pyramids were built with a lime mortar. It is said it took 500,000 tons of mortar to build the external casing stones of the Great Pyramid at Giza. Around the same time China was using a form of concrete to build the Great Wall. Interestingly also adding another key ingredient into the mix, sticky rice.

The world continues to see the success of the Roman Empire to this day. The Pantheon in Rome is still the world’s largest unreinforced concrete dome. The Colosseum and Roman Baths also account for this civilization’s advanced knowledge and sophistication. But after the fall of the Roman Empire in 476 A.D., the technology was lost during the middle ages. Fast forward to around 1415 when information was found and the regeneration of concrete building began. Like anything it took time, but eventually a new process made Portland cement possible, changing the shape of history. Before 1824 when Portland cement was patented, there were patents for various cements around Europe. Globally, larger projects brought larger demands, including the Erie Canal which started production in 1817 using locally sourced hydraulic cement. By 1868, Europe saw their first shipment of Portland cement to America.

In modern times in the US, concrete using Portland cement progressively shaped our world, our landscape and our opportunities. Portland cement was a material used in forty-nine of Thomas Edison’s patents, including many apparatuses for manipulating cement, as well as a new building design. The first concrete highway was built in 1909 in now Northwest Detroit. The Hover Dam was a first of its kind, leading the way to further productions like the Grand Coulee Dam in Washington State. Seen to completion by President Roosevelt, the Grand Coulee Dam created power than fueled growing industries here in the Northwest during World War II.

The impact

From skyscrapers and underwater pipelines, to planter boxes and kitchen sinks, advancements in concrete have shaped the way we live our lives to this day, and will most certainly continue. Reinforced concrete is the only material on Earth resistant to both fire and water. It keeps us safe and operating comfortably daily. Today unlike 100 years ago, concrete is seen as a pleasing finish in homes, inside and out. Interior designs using large slabs of concrete for walls, fireplaces, counter tops, shower stalls and floors are not only durable and long-lasting, but eye catching in their unique simplicity.

With advancements around the world, we can continue to find amazement in concrete and its applications. To reduce the resulting Carbon Dioxide emission from production, there have been creative advances in science that give us even more options when looking at our Carbon footprint. Environmentally friendly applications have brought us self-healing concrete, a bio-concrete that repairs itself when exposed to water. If that isn’t cool enough, companies like ECOncrete make seawalls, blocks and mats that support growth of flora and fauna, positively effecting marine biodiversity. On land they offer bio-active walls that promote growth of vegetation on buildings. There is no doubt our innovative efforts to decrease the energy we create from concrete now will positively effect our lives in the future. Concrete continues to impress, the Jubilee Church in Italy is made from an emission absorbing concrete that ‘eats’ Carbon Dioxide in the curing process, minimizing the carbon footprint.

Concrete in all of its forms, from conception to present day, is a testament to humankind’s will-power and intelligence. Through necessity, we have shown that our knowledge of this material is as vast as our use of it. The next time you are on a walk, take notice of the walls and ground you are interacting with. Its stability supports you as you take on life.

If the time you took reading this brings a little more gratitude to your day as you walk through life, we are happy. Thank you for enjoying the little things in life with us, they really do make the biggest impact.

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