(POINT 01)

What is reduced-cement concrete?

Cement, one of the primary components of concrete, needs to be manufactured at high heat (1,450℃). As a result, a large volume of CO₂ is emitted from the limestone used to make cement. In fact, cement manufacturing is responsible for about a quarter of the CO₂ emitted during building construction.

Reduced-cement concrete is a product in which cement is partially substituted with other materials to lower the volume of CO₂ emitted during the manufacturing process.

Our reduced-cement concretes include Eco-Crete R³, which is made from recycled cement manufactured from unused concrete at construction sites, as well as Eco-Crete ECM, Eco-Crete KKC, and Eco-Crete BLS, in which we have partially substituted industrial by-products for cement. Each of these reduced-cement concretes is suited for a different aspect of construction, and by using all of them we can greatly lower the amount of CO₂ emitted during construction.

(POINT 02)

Eco-Crete R³: Recycling cement from unused concrete

About 1-2% of concrete at a construction site goes unused for unavoidable reasons and gets discarded. However, by removing water and aggregates from this concrete and then pulverizing it, the cement in the concrete can be recycled. This is how we produce Cem R³, a recycled cement that we use to make our Eco-Crete R³ concrete.

Standard cement must be manufactured at a high temperature (1,450℃), which results in CO₂ emissions of about 750 kg per ton of cement. Because Cem R³ is manufactured at much lower temperatures (150-600℃), CO₂ emissions are about an eighth of standard concrete.

There are two types of Eco-Crete R³, each containing a different volume of Cem R³ to cater to different needs. The high-Cem R³ type, the manufacturing process of which results in a 90% cut in CO₂ emissions, is suitable for precast framing products such as slabs.* The low-Cem R³ type, the manufacturing process of which results in a 20% cut in CO₂ emissions, can be applied to a wider range of products, such as blocks and other concrete products, as well as ready-mix concrete.

* Precast framing products: Factory-made standardized concrete products that are needed to assemble the building frame

(POINT 03)

Eco-Crete ECM, Eco-Crete KKC, and Eco-Crete BLS: Concretes that substitute industrial by-products for cement

In these concrete products, the cement is partially substituted with dried and pulverized blast furnace slag, a by-product of steel manufacturing. Like cement, powdered blast furnace slag hardens when it reacts with water. The substitution allows us to reduce the volume of cement in the concretes and emit less CO₂ to manufacture them.

The attribute of the concrete differs based on the volume of powdered blast furnace slag in its composition. For example, Eco-Crete ECM, which contains 60-70% powdered blast furnace slag, is suitable as mass concrete used in the underground structure of a building. Eco-Crete KKC, which contains 40-45% powdered blast furnace slag, is best for concrete-filled steel tubes used in columns and other structures. Eco-Crete BLS, which contains 20-30% powdered blast furnace slag, can be used in a range of overground structures, such as walls and floors. The higher the volume of powdered blast furnace slag in the concrete, the greater the cut in CO₂ emissions in the manufacturing process.

（POINT 04）

The impact of reduced-cement concrete

By using all three types of reduced-cement concretes in the construction of an average office building, we can cut overall CO₂ emissions by about 10%—or about the volume of CO₂ that can be captured by 108,000 cedars in a year.