Cement is a strong binding agent, (and the most popular binder used in construction), which serves as the primary ingredient in concrete. Concrete plays an important role in construction as a critical component in foundations, structures, roads, bridges, highways, and more. The production levels of cement continue to rise every year. Last year, the world produced 3.6 billion tons of cement, -accounting for approximately 8% of global CO2 emissions- and that amount could increase by a billion tons by 2050.
The key ingredient is limestone, mostly calcium carbonate, the remains of shelled marine creatures. The recipe for making cement calls for heating the limestone, which requires fossil fuels. And when heated, limestone sends carbon dioxide gas into the atmosphere, where it traps heat, contributing to global warming. Cement production is responsible for 5 percent of the world’s human-produced carbon dioxide emissions.
People have been trying to build a better cement since just about the beginning of history. More than 2,000 years ago, the Romans devised a mixture of lime, volcanic ash and chunks of stone to form concrete, which was used to make harbors, monuments and buildings including the Pantheon and the Colosseum. In the 1820s, in Leeds, England, about 200 miles from Imperial College, a stone mason named Joseph Aspdin invented modern cement. Aspdin heated a concoction of finely ground limestone and clay in his kitchen. After he added water, the mixture hardened. Voilà—the building block of the Industrial Revolution was born.
As an initiative to bring down the threats produced by emission, the manufacturing process of cement can be suitably altered to bring down the emission levels significantly. Green cement is a form of cement produced with the help of a “carbon-negative manufacturing process.” In other words, cement produced as the final product of a technologically advanced process, such that emissions during unit operations are minimized, is referred to as green cement. Green cement is an eco-friendly product which resolves serious environmental issues and minimizes the carbon footprint of cement production. Compared to other conventional cement, green cement offers fire resistance and has a longer setting time but Structures built from green cement have a longer life span.
There are multiple types of green cement that differ depending on the technology used to make them.
- Calcium Sulfoaluminate Cement
- Geopolymer Cement
- Sequestrated Carbon Cement
- Ekkomaxx Cement
- Ferrocrete
- Magnesium Oxychloride Cement
Incorporating green cement in construction instead of conventional cement would be a major step toward mitigating the climate crisis and preserving the environment.