Zhyar Yahya Abdulkareem
Civil Engineering Department
Abstract
After water, concrete is the most utilized substance on the planet. Its key ingredient cement is one of the biggest contributors to our climate crisis responsible of %8 of world’s co2 emissions.
If the cement industry was a country, it would be the third largest emitter in the world — behind only China and the US. But what if those pollutants could be harnessed to create environmentally friendly and sustainable solution? Can the cement industry correct its carbon footprint and become more sustainable in the long term? What is low carbon cement and what is its relation with sustainability?
In this study we are going to answer these questions and discuss how low carbon cement can revolutionize the future of civil engineering to make building materials more environmentally friendly and sustainable.
Introduction
Low carbon cement products use less carbon than ordinary Portland cement paver. In the production of cement that is the primarily emissions problem because it takes huge amounts of fossil fuel energy to actually produce tonnage of cement.
Ordinary cement emits greenhouse gases in two ways: its fossil fuels to heat limestone at super high temperature, and when the limestone chemically transforms, that process releases co2 into atmosphere. But in low carbon cement uses co2 emissions in the product or reuses the waste of other industrial for cement.
What is low carbon cement?
Researchers have made numerous attempts so as to produce concrete with lowest possible CO2 emissions, Production of low carbon concrete starts from quarry of raw materials to produce cement and production of concrete.
Although low-carbon cement alternatives have been under development for decades, increased concerns about global warming have ramped up interest over the past decades, increased few years
Method
It is claimed that recycling construction wastes and rubbles could decline CO2 emission by nearly 6%. Added to that, reusing resources and importing regional materials decline CO2 emissions by around 3%.
Slags from the non-ferrous metallurgy, chemically situated in the CaO-FeOx-SiO2 system, can be used as raw material for alkali-activated materials, a sustainable alternative to Portland cement.
Meanwhile, global cement manufacturer Discussion has joined forces with startup company Solidia Technologies. Solidia produces cement hardens by adding CO2 instead of water — a so-called carbon-cured cement — which the company says reduces the overall carbon footprint by up to 70%.
Solidia’s product is still undergoing a variety of tests and not yet approved for use in building codes.
Discussion
Solidia is a cement and concrete technology company, offering patented green solutions that make it easy and profitable to use CO2 to create superior, sustainable building materials. The technology has the potential to eliminate a minimum of 1.5 gigatons of CO2 each year.
Solidia provides two core technologies:
- A sustainable cement manufacturing technology, which can be produced in traditional cement kilns using less energy, reducing greenhouse gas emissions during manufacturing by 30-40%.
- A sustainable concrete curing technology, curing concrete with CO2 instead of water, and safely consuming 240kg of CO2, potentially saving 3 trillion liters of fresh water every year.
Solidia cement
- Reduces co2 emissions
- Requires less energy
- makes more cement with less raw material
CO2-cured concrete products
- Perform higher
- Cost less to produce
- Cure in less than 24 hours opposed to the traditional concrete that take 28 days
Portland cement concrete
The production of cement releases greenhouse gas emissions both directly and indirectly: the heating of limestone releases CO2 directly, called calcination (50%) while the burning of fossil fuels to heat the kiln indirectly results in CO2 emissions. This is around 40% percent of cement emissions.
Low-carbon (blended) cement
CEM II, CEM III, CEM IV, CEM V-Packed cement include any cement conforming to BS EN 197-1:2011, but other than CEMI. It is commonly referred to as ‘low-carbon’ as it contains lower proportions of clinker. Generally, it comprises Portland cement clinker combined with one or more additional supplementary cementitious material(s) and an optimized amount of gypsum.
CONCLUSION
To sum up, we understand that our current method of producing cement is not very sufficient, environmentally friendly, or sustainable. As it was discussed before, sustainability requires one or both of these factors factors:
- Recyclability
- Continuous
These are the examples of Supplementary Cementitious Materials (SCMs) which are recycled
- Product from steel industry
- Fly-ash: by-products from the coal power plant
- Limestone fines: milling limestone
- Silica fume: by-product from the silicon metal and ferro silicon alloys industry
And the example of continues factor of sustainability which applies to our example of carbon curing, carbon curing reducing curing time and save a lot of fresh water and the source of the CO2 is continues because the process of making cement produce a lot of CO2 so we can use that CO2 for curing and it is a new sustainable technology which is environmentally friendly.
REFERENCE
- Sustainability in Constructions using alternative materials: An effort towards moving to net Zero emissions & sustainable concretes / LAP LAMBERT Academic Publishing
- Madeh Izat Hamakareem Low Carbon Concrete and Its Advantages 2019
- Sustainable metrials / julian M. allwood