Special cement introduction
Special cements are cements that serve some specific function such as altering the setting or hardening behavior of a concrete, producing different colors for architectural effects, imparting superior workability, imparting water retention and plasticity to mortars, resisting the penetration of water in walls or containment vessels or simply reducing the cost of the cementing agent. This article gives descriptions of the basic characteristics of certain special cements and their applications.
Those described include: calcium sulfoaluminate cements, calcium aluminate cements with special setting and hardening properties, cements with special colors (white Portland and buff-colored).
Calcium Sulfoaluminate cement
is special cement because of its high-speed bonding, rapid strength development, and a shrinkage reduction. We also called them as CSA Cement in short. Oreworld CSA cements are classified by two types: one is CSA cement and the other is CSA binder which does not add anhydrite but CSA pure clinker powder.
The CSA cements have three grades classified by the strength in three days; CSA42.5, CSA52.5 and CSA 62.5.
Regarding the CSA binder, there are three grades, too. They are CSA binder 52.5, CSA binder 62.5 and CSA binder 72.5. The CSA binder is pure CSA clinker powders that without adding anhydrite. Most of the traders or plants who have their own plants and can mixing the anhydrite like the CSA binder best because it can save production and transportation cost.
The CSA binders can be produced to different types of dry-mix mortars based on CSA cements. For example, self-leveling mortar, concrete repair mortar, tile adhesives, no-shrinkage mortar and etc.
Special cement Characteristics
• Appearance: light grey powder
• Early-high strength
• Rapid setting: initial setting time can reach 12~20 minutes
• Tiny expansion and low shrinkage
• Low degree of shrinkage
• Low alkali: PH value is about 11 and lower than Portland cement.
• No rust to steel
• Freeze-thaw resistance
• Resistance to sulfate attack
• Low carbon footprint
Special cement Application
• Concretes repair (for example bridges, airport runaways and parking apron, etc.)
• Technical Rapid-Setting Mortars (for example restoration and repairs, etc.)
• Self-Leveling Floor Screeds
• Sprayed Concretes and Shotcretes
• Mining Products, for example: mining roof support materials.
• Plasters & Mortars (i.e. Joints, Sulfate Resistance, No-Shrinkage, etc.)
• Special adhesives, tile adhesives
• Concrete Precast Products
• Glass fiber reinforced concrete (G.R.C.)