Lesson 7. Cement Binder

In the previous lesson, we completed the analysis of gypsum binder, identifying its strengths and weaknesses. Today we move on to the strongest and most universal component in the mineral binder group — cement. In this lesson, you will learn how cement solves the problem of water resistance and strength, surpassing lime and gypsum, while at the same time imposing its own limitations on vapor permeability and the aesthetics of the final coating.

What is Cement Binder?

Cement binders (based on Portland cement) belong to the class of hydraulic binders. Unlike lime, cement hardens not through reaction with air, but through a chemical reaction with water — a process called hydration.

During hydration, an extremely strong, dense, and needle‑like crystalline structure is formed, known as “cement stone.” This irreversible process defines all the key characteristics of cement coatings: their exceptional strength, water resistance, and specific aesthetics.

The main areas of application for cement compositions are facades, floors, wet rooms, and coatings requiring maximum wear resistance.

Influence on Operational Factors

Interaction with moisture

• Water resistance: Very high. Cement is not afraid of direct contact with water and serves as the basis not only for decorative materials but also for concrete used in hydraulic structures. Cement binder makes decorative coatings resistant to splashes, wet cleaning, and even short‑term flooding. Protection can be further enhanced with wax, varnish, or hydrophobic impregnation. This makes cement decorative materials an excellent solution for durable and reliable finishes in wet zones.
• Moisture resistance: Very high. Cement binder is completely unaffected by air humidity and does not lose strength even with prolonged exposure to high humidity. It does not soften or change properties with humidity fluctuations, making it a reliable base for decorative coatings in bathrooms, saunas, kitchens, and other areas with a humid microclimate. Even without additional protection, such materials remain stable, and if necessary, they can be reinforced with moisture‑resistant finishing products.
• Vapor permeability: Low. After hydration, cement forms a dense, low‑porosity structure that weakly transmits water vapor. This makes it a reliable vapor barrier, which can be advantageous in certain zones but requires careful consideration when applied to mineral “breathing” substrates. Blocking vapor escape from walls can lead to moisture accumulation beneath the coating, so compatibility of layers in the finishing system must be considered according to their vapor permeability levels.
• Wet abrasion resistance: Very high. Cement coatings, such as microcement, easily withstand regular wet cleaning with sponges, brushes, and household detergents. The surface retains strength and appearance even under intensive use, making such materials an excellent choice for kitchens, bathrooms, hallways, and other zones with high load and frequent cleaning requirements.
• Resistance to biological damage: High. During hydration, cement creates an alkaline environment with high pH, unfavorable for mold, fungi, and most microorganisms. Thanks to this property, cement decorative coatings are well suited for rooms with high humidity and limited ventilation.

Interaction with Mechanical Impact

• Abrasion and scratch resistance: Very high. Cement binder forms a hard, dense surface resistant to mechanical damage. Such coatings withstand contact with abrasive particles, impacts, furniture, or frequent friction. Thanks to this, cement‑based decorative materials are suitable for high‑traffic areas, retaining their appearance even during long‑term use. This is one of the most durable and wear‑resistant binders.
• Impact resistance: Very high. Cement coatings withstand localized and sudden mechanical loads well, without chipping or cracking under accidental impacts. Due to their high density and compressive strength, these materials are widely used in areas with heavy operational loads — for example, public spaces, staircases, entryways, and technical zones.
• Elasticity and crack resistance: Very low. In its pure form, cement is extremely rigid and brittle under bending. To improve elasticity, modern decorative cement compositions (such as microcement) include large amounts of polymer additives. These additives increase flexibility, improve adhesion to the substrate, and allow the coating to perform in a more adaptable mode, reducing the risk of cracking.

Other Specific Operational Factors

• UV resistance: Very high. Cement binder is mineral‑based and completely inert to ultraviolet radiation. It does not fade, lose strength, or degrade under sunlight, making it a reliable base for decorative coatings both indoors and on facades. However, pigments used for tinting may vary in lightfastness — they are more prone to fading than the cement itself.
• Heat resistance: Very high. Cement binder is the basis of heat‑resistant concretes and is naturally stable under high temperatures. In decorative plasters, this allows confident use near fireplaces, chimneys, and radiators. Unlike polymer coatings, cement systems do not soften or emit harmful substances when heated. However, modern decorative compositions are cement‑polymer blends, and their final heat resistance may be limited by polymer additives and pigments. In multilayer décor, the decisive factor may be the finishing protective varnish, paint, or wax, which usually has a lower temperature threshold. This determines the maximum operating temperature of the entire system, which can reach up to 150 °C or higher.
• Frost resistance: Very high. Cement binder can withstand repeated freeze‑thaw cycles without losing strength or adhesion. This is why it is used as the basis for facade and outdoor decorative coatings in any climate. With proper substrate preparation and protection from excess moisture, cement plasters remain stable even in severe winters.
• Storage and transport: Dry cement mixes also show high stability. They are not affected by sub‑zero temperatures and do not require special conditions in cold seasons. The main requirement is protection from moisture: if the dry mix becomes wet, hydration begins, and the material becomes unusable.
• Environmental safety: Medium. Hardened cement itself is inert and safe. However, cement dust during work is aggressive and requires the use of personal protective equipment.

Influence on Aesthetic Factors

• Color and tinting: Limited. The tinting possibilities of cement materials are restricted by several factors. First, the natural gray color of standard Portland cement mutes pigments, making shades appear “dusty.” To achieve clean colors, more expensive white cement must be used. Second, the high alkalinity of the binder requires only inorganic, alkali‑resistant pigments, further narrowing the palette of bright tones. Even after selecting pigments, risks remain during drying: in systems with high cement content, areas that dry faster (thinner layers) may appear lighter, causing uneven coloration. Additionally, white salt deposits (efflorescence) may appear on surfaces, especially on dark colors, due to salts migrating with moisture from the substrate or the mix itself. It should be noted that in modern decorative materials, such as high‑quality microcement, the risk of efflorescence caused by the coating itself is minimized thanks to polymer additives.
• Texture and relief: Highly versatile. Cement decorative materials allow the creation of a wide range of visual and tactile effects — from thin smooth coatings with soft matte sheen or strong finishes like microcement, to expressive reliefs imitating concrete, stone, rock, or architectural elements. Results depend on composition, additives, application technique, and tools used. This versatility makes cement especially valuable for modern interiors in loft, industrial, minimalist, and other styles.
• Gloss level: From matte to glossy. The surface can be left matte or polished mechanically to achieve high gloss, similar to natural stone.
• Optical effects: Cement coatings do not create depth, shimmer, or iridescence like Venetian plaster. Their visual expressiveness is built on texture, natural color transitions, tool marks, slight shade variations, and traces of handwork. This is an aesthetic of strength, texture, and rawness, highly valued in modern interiors emphasizing naturalness and simplicity of form.

Conclusion

We have thoroughly studied cement binder and confirmed its status as the champion of strength, water resistance, and wear resistance among mineral materials. Cement, especially when combined with polymer additives, gives the craftsman the ability to create coatings that withstand heavy loads and moisture.

At the same time, we have seen its drawbacks: low vapor permeability and limitations in achieving pure colors.

In the next lesson, we will move on to silicate binder. You will learn how this material combines exceptional strength with excellent vapor permeability.