Water-reducing additives: cutting costs and emissions

In recent years, the same technology has been successfully applied in multiple cement productions by MAPEI, representing a new horizon for reducing operational costs and CO2 emissions by enabling the use of low-clinker cements – fully in line with the current demands of the global cement industry. Low-clinker cements incorporate a high content of supplementary materials to replace part of the clinker, including limestone, pozzolan, calcined clay, demolition waste, recycled concrete, and bricks. The materials usually have a layered and/or porous microstructure that tends to absorb and retain a large amounts of liquid during mixing.

As a result, low-clinker cements frequently encounter:

• Higher water demand.
• Loss of workability.
• Lower mechanical strength.

The performance of cement can be evaluated through various standardised testing though mainly in mortar. For example, ASTM C109 specifies that blended cements (except Type IL) should be tested at the flow of 110 ± 5 by adjusting w/c (water to cement) ratio. Compared to clinker-rich cement, blended cements require more water to reach the flow that leads to lower strength. While with EN 196-1, all the cements should be tested at fixed w/c ratio of 0.50 instead, regardless of cement types. When the cement has a large amount of secondary materials, the workability of the mortar is adversely affected, and the same occurs in concrete. The latter requires adjustments of the w/c ratio, usually involving a greater volume of water, admixtures, or cement – changes that are not always thoroughly assessed by professionals in the ready-mix industry.

Towards both standards and concrete as the end user of cement, the challenge of low clinker cement remains in balancing the increasing demand of clinker reduction and meeting the performance requirements.

This is exactly where MAPEI’s product line of MA.P.E./C-C WR works effectively. Designed to provide a viable and versatile route, it enables the supply and subsequent application of low-clinker cements, made with one or more types of supplementary materials.

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Read the article online at: https://www.worldcement.com/special-reports/24092024/water-reducing-additives-enhance-sustainability-and-lower-cement-costs/