Cement (CEM I)

Cement has been used as a construction material for thousands of years and is made from limestone and clay. Concrete is made by mixing cement with water, sand and gravel. The cement types that are investigated in this project are CEM I (Portland cement), CEM II (A & B) which are Portland cement composite. Cement, especially Portland cement (CEM I), is a major contributor to global CO₂ emissions due to its energy-intensive production. Circular economy practices focus on reducing the use of clinker, the most carbon-intensive component. Refuse strategies include developing alternative binders like alkali-activated materials. Reduction is achieved by replacing clinker with industrial byproducts such as fly ash or slag, which can reduce clinker content by up to 60%. Remanufacturing includes reusing expired cement and internal process waste. Recycling of concrete fines into new clinker is being tested at pilot scale, and recovery of energy from industrial byproducts is common.

At the end of life, cement itself is not directly reused, but the concrete it forms can be crushed and recycled. Aggregates can be reused in road construction, and cement paste may be separated and reused in new cement production, although this remains technically challenging.