Making Concrete Lighter and Less Carbon Dependent

Chris d Craiker ALA/NCARB

Concrete is among the most energy consuming products on Earth. Concrete consists of water, aggregates, binders, reinforcing materials as steel, of course, cement. The process of converting limestone, the primary binding component, to lime requires an enormous amount of heat that emits CO2. It's estimated that one quarter of all the world's industry carbon emissions come from the creation of cement. Currently, over 30 billion tons are produced annually and as the world gets more urbanized, and more high rises are built to house exploding populations, the quantity is expected to increase exponentially in this Century.

The primary product we use today is called Portland cement, named after the English city of Portland where 200 years ago it was created. While cement was known to the Romans, today's product is far more effective and stronger.

Both universities and manufacturers are investigating various methods of producing concrete more efficiently and stronger. Here are a few processes on the horizon:

• Separating lime from the limestone via electrolysis preferably using renewable energy. The process requires electricity to separate the lime.

• A percentage of lime produced can be replaced with supplementary cementitious materials, such as fly ash, slag, and silica fume, which are waste materials from industrial process.

• Use Limestone Calcined Clay Cement (LC3): This type of cement can reduce CO2 emissions by around 40% compared with conventional cement.

• Use alternative binders: Substitute cement with more traditional alternative binders, such as fly ash, ground granulated blast furnace slag (GGBS), calcined clays, and natural pozzolans.

• Use renewable energy equipment that runs off renewable energy or biofuels. In the big picture, switch from coal to renewables.

• Carbon capture and sequestration: Manufactures are pushing capturing CO2 from the industrial plants or direct air capture facilities and mineralize it in concrete. This prevents the CO2 from entering the atmosphere.

All of these concepts are on the horizon, but they need us to encourage low carbon products in our everyday lives. Eliminate the use of plastics or at least reuse as much as possible of what you have and only use recyclable products. Construction can become more efficient and energy productive by making low carbon footprint steps. Even the equipment we use in the field can use renewable energy or biofuels. Recycling of materials and using those recycled materials in the construction can make a big difference. If we wish to make a low carbon footprint, we need to start with the products and processes.

Ask The Architex

With the recent overthrow of the Syrian Dictator Assad, few Americans know or think about Syrians in their day-to-day. Nobody has heard of Amos Muzad Yaqoob Kairouz, but a young American born Syrian comedian/actor, a seemingly impossible combination, was struggling with a baby on the way. Desperate, he turned to St Jude Thaddeus, patron saint of lost causes. He vowed, “show me my way in life, and I will build you a shrine.”

It was pivotal for him and Amos soon became Danny Thomas, a major TV star in the 60s as a singer, actor and producer of “Make Room for Daddy” and “The Danny Thomas Show”. His daughter, Marlo was a TV sensation in the 60’s. Not forgetting his oath, he with his Lebanese and Syrian associates opened in 1962 Saint Jude's Hospital in Memphis, Tennessee. The first clients were leukemia patients that were successfully removed from therapy. The fund-raising arm of St Jude is the largest healthcare related charity in America. It is now the World’s largest long-term clinic for pediatric-children- cancer patients. Marlo is still very much involved. All from an oath by a complete unknown.

Chris d Craiker ALA/NCARB is proud of his Syrian, Irish and German heritage