Table of Contents
Introduction of Magnesium Phosphate Cement
Magnesium Phosphate Cement gains its strength in a very low time compared to traditional cement. It hardens very fast and achieves high strength in a short time, reaching the strength level of ordinary portland cement within a few hours. Magnesium phosphate cement binder is produced by the reaction of magnesium oxide and phosphate in water at room temperature.
Magnesium phosphate cement binders have several advantages over regular portland cement binders. It not only hardens quickly, but also has high strength and excellent durability.
Magnesium phosphate cement can adhere to a variety of substrates including concrete, metal, wood, asphalt and various plastics. Magnesium phosphate cement binder systems are primarily used for rapid curing and hardening of dry shotcrete mixes, patch mortar or dry mix products and protective coatings.
How to Handle MPC Magnesium Phosphate Cement
Magnesium phosphate cement concrete mixtures give off considerable heat. Therefore, maximum precautions should be taken when handling the material. Do not leave magnesium phosphate cement in or on equipment after mixing with water. For this reason, it is recommended not to add water to the dry magnesium phosphate cement mix prior to placing the material.
Cure times of 10-20 minutes are most common, leading to early strength development of 14 MPa within 2 hours. Can be extended to 45-60 minutes at room temperature when mixed with a retardant.
Characteristics of Magnesium Phosphate Cement
- Good durability.
- High strength.
- Low shrinkage.
- Low permeability
- Abrasion resistance equivalent to ordinary portland cement concrete.
- Resists bumps and scratches.
- Low conductivity.
- Good thermal conductivity.
Advantages
- Sustainable technology is used to manufacture the magnesium phosphate cement.
- Starts up quickly and gains power early. Rapid remediation of patches can be economically accomplished with magnesium phosphate cement.
- Excellent freeze-thaw resistance.
- Low shrinkage properties eliminate shrinkage cracks.
- Resistance to water penetration by formation of insoluble complexes. This insoluble formation is formed when soluble phosphate is mixed with magnesium phosphate cement concrete.
- Non flammable and fire resistant
- Adhesion with various components and substrates.
- Corrosion resistance.
Disadvantages
- The reaction between the aerated surface (calcareous aggregate) and the phosphoric acid produces carbon dioxide (CO2) that weakens the bond of the paste aggregate. Magnesium phosphate cement chemically reacts with fractures and carbonate zone dust, reducing the bond strength at the bond interface.
- Magnesium phosphate cement cannot be applied in a dry pack state (water content cannot be adjusted) and cannot be applied with a hard trowel.
- Deviations in moisture content from the values specified by the manufacturer reduce both the strength and durability of magnesium phosphate cement mortars.
- Magnesium phosphate cement can be easily washed off with copious amounts of water while wet or within 10-15 minutes after application, but is very difficult to remove once hardened.
Usage
- High-speed patching of bridge and road mixes; repair of reinforced concrete structures.
- Hazardous and nuclear waste encapsulation.
- Shotcrete applications.
- Mortar for carbon fiber reinforcement.
- Permafrost, cryogenic applications such as anticorrosion and coating.
- Manufacture of magnesia-based refractory concrete for fire protection coating applications.
- Improves water resistance of Sorel cement.
- Production of concrete with high initial strength.