Building Strength For A Greener Future

The cement industry is at a turning point. As the world races to fight climate change, producers are stepping up to cut greenhouse gas emissions and help achieve global net zero goals. One of the most impactful changes was the shift from traditional ordinary portland cement (OPC) to portland limestone cement (PLC), which significantly reduces CO₂ emissions. However, this transition comes with a critical challenge: maintaining the same physical properties – especially early compressive strength – that builders rely on for safety and speed. This article introduces a powerful new tool designed to help cement producers overcome this challenge. With the correct approach, the industry can continue delivering strong, durable structures while meeting ambitious climate targets. Because sustainability should not mean compromise – it should mean progress.

Strength enhancement

Grinding aids are the chemical additives incorporated during the cement grinding process. They are added to the clinker to improve grinding efficiency and to enhance the final properties of the ground cement. For instance, these materials are mainly used to optimise the grinding process by enhancing cement particle dispersion and facilitating the formation of particles with target sizes. A special class of additives based on oligomeric siloxane chemistry (also called silicone booster aid) has shown the capability to further improve the performance of existing grinding aids. These compounds lower the surface tension of the solution present in the grinding process. This allows the combined solution (grinding aid + booster aid) to spread more easily over the surfaces of cement particles and interact more thoroughly with silicates and aluminosilicate minerals in the cement matrix, offering physical properties that are difficult to achieve with traditional approaches. For instance, this effect could potentially help achieve the following benefits:

Improved particle dispersion

Silicone booster aids help to increase the spreading of grinding aids more sufficiently over cement particles, which facilitates the effective dispersion and reduces agglomeration of cement particles, thus improving the grinding efficiency.

Enhanced fineness

Better dispersion may allow for finer grinding, increasing the surface area of cement particles. Finer cement generally hydrates more completely and rapidly, which can contribute to higher early strength.

The result is a more efficient grinding process, improved mill throughput, and a notable increase in compressive strength in blended cements such as limestone- or slag-containing cement, without altering their mineral composition.

Silicone chemistry: wetting agents and hydrophobisation

Silicone-based additives, especially those derived from oligomeric siloxane chemistry, offer unique benefits as both strength enhancers or hydrophobisers. Their molecular structure allows them to modify the surface properties of cement particles, not only by imparting hydrophobicity (protecting against moisture and pre-hydration), but also by reducing surface tension (improving wetting and dispersion).

The silicone booster aids, acting like surface tension reducers, facilitate the uniform distribution of grinding aids during cement grinding and sufficient contact area with cement grains, leading to more efficient interaction and improved strength development. This is especially important for ensuring the high performance of cement-based products, where uniformity and consistency of cement are paramount.

Conversely, hydrophobisation is essential for speciality cements that require extended storage or are exposed to high humidity. Oligomeric siloxane emulsions, such as ‘SILRES BS Cement Stabilizer’, have been shown to stabilise cement and prevent strength loss during storage at high humidity, with modified cements maintaining their properties, while unmodified cements lost up to 90% of their activity. This dual functionality, i.e. enhancing strength and protecting against moisture, makes silicone chemistry a versatile tool for modern cement production.

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Read the article online at: https://www.worldcement.com/special-reports/25022026/building-strength-for-a-greener-future/