The Green Side of Concrete: A Sustainable Resource for the Ages

Concrete is a predominant building material globally, but it has not been immune to scrutiny. Many point fingers at its environmental impact, especially the carbon emissions from cement production.

However, beneath this gray façade lies a green side many might not know about. Dive into how concrete has emerged as a sustainable material and discover its role in steering the construction world toward a greener tomorrow.

1.      Recycled and Supplementary Cement Materials (SCMs)

Traditional cement binds concrete and is a significant source of CO2 emissions. However, advancements in concrete mix designs have led to the incorporation of recycled materials like fly ash (from coal combustion), slag cement (from steel production), and silica fume. Not only do these SCMs reduce the need for fresh cement, but they often enhance the durability and workability of the concrete.

2.      Environmentally Sustainable Steel Reinforcement

An integral part of any concrete structure is the steel rebar that reinforces it. In the United States, one of the methods used to produce rebar is through an Electric Arc Furnace (EAF). Rather than a Basic Oxygen Furnace (also commonly referred to as a blast furnace), which relies on iron ore and other ingredients to produce steel, EAFs use recycled scrap metal as the primary source of material for their steel mills. By giving new life to recycled scrap metal, EAF steel producers like CMC can minimize the environmental impact they may have while producing steel rebar that provides strength and reinforcement to concrete.

3.      Carbon Capture in Concrete

Emerging technologies are allowing for the capture and storage of carbon dioxide within concrete. Some innovative companies use captured CO2 to cure concrete, effectively locking away the greenhouse gas within the material. This not only reduces the carbon footprint but also enhances the strength of the concrete. 

4.      Concrete’s Longevity & Durability

One of concrete's most significant green assets is its lifespan. Structures made from concrete are durable and can last centuries, meaning fewer resources are needed for repairs and replacements than other materials. Over its lifespan, the environmental impact of a concrete structure can be considerably lower than alternatives that require frequent maintenance.

5.      Urban Heat Island Mitigation

Concrete can be formulated to be reflective, bouncing back a significant portion of the sun’s rays and reducing the urban heat island effect. This can help cities stay cooler and reduce the need for air conditioning, further diminishing energy consumption.

6.      Permeable Concrete

This type of concrete allows water to pass through it, reducing surface runoff, recharging groundwater, and minimizing the risk of flooding. Using permeable concrete in urban areas can better manage rainwater and contribute to more sustainable urban ecosystems.

7.      Building with Insulated Concrete Forms (ICFs)

ICFs are forms for poured concrete walls, filled with rigid thermal insulation that stays in place as a permanent interior and exterior substrate. This leads to better thermal performance, reducing the energy needed to heat and cool buildings. Buildings made with ICFs are also highly resilient against natural disasters, minimizing the need for reconstruction.

8.      Future Innovations

Living Concrete Researchers are delving into the ‘living concrete’ realm, which incorporates bacteria. These bacteria can “heal” cracks that appear over time by producing calcite, a natural cement, thus prolonging the structure's lifespan and reducing maintenance needs

Concrete, when seen from a broader perspective, has many green qualities that can make it an eco-friendly choice for construction. It’s essential to look beyond the initial carbon footprint and consider the material's entire lifecycle, from production to disposal.

As the industry continues to innovate, there's every reason to believe that the green side of concrete will shine even brighter in the years to come. This timeless material, which has been the backbone of civilizations for millennia, adapts to the demands of our eco-conscious era and promises to be a sustainable resource for the ages.

For over 30 years, Tendon Systems, now a part of CMC has been an industry-leading provider of post-tensioning, barrier cable, and restoration services across the United States. Built on a foundation of quality products, exceptional services, and engineering expertise, the Tendon team has what your project needs to succeed on time and within budget.