What is the strongest type of plaster in New Zealand?

In New Zealand, the strongest type of plaster commonly used is cement-based plaster, also known as cement render or cementitious plaster. Cement plaster is known for its strength, durability, and resistance to cracking and impact. It is widely used for both interior and exterior applications.

The scientific explanation behind the strength of cement-based plaster lies in its composition and chemical reaction. Cement plaster is typically made by combining Portland cement, sand, water, and sometimes additional additives such as lime or polymers. The specific proportions of these components can vary based on the desired properties and application requirements.

The strength of cement plaster is primarily attributed to the chemical reaction that occurs when water is added to the cement. This reaction, known as hydration, leads to the formation of calcium silicate hydrate (C-S-H) gel, which binds the aggregate particles together and hardens over time. The C-S-H gel provides the plaster with its structural integrity and strength.

Furthermore, the presence of sand in cement plaster enhances its strength by acting as a reinforcement and filler material. The sand particles interlock, creating a solid matrix that contributes to the plaster’s overall strength and resistance to cracking.

The addition of additives such as lime or polymers can further enhance the strength and performance of cement-based plaster. Lime can improve workability, durability, and adhesion, while polymers can increase flexibility, water resistance, and impact resistance.

It’s important to note that the specific composition and properties of cement-based plaster can vary based on manufacturers and product formulations. Different brands may have their own proprietary mixtures and additives, resulting in slight variations in performance and characteristics.

Overall, cement-based plaster is favored for its strength and durability, making it suitable for a wide range of applications, including residential and commercial buildings, as well as high-traffic areas.