Key words
Calcium Stearate, Concrete, Water Repellent, Foam Stabilizer
Calcium stearate is an organic compound with a molecular formula of C36H70CaO4, a white powder, insoluble in water, and can be used as a waterproofing agent.
Appearance and properties: white solid
CAS number: 1592-23-0
Molecular formula: C36H70CaO4
Density: 1.08g/cm3
Melting point: 147-149 C
Boiling point: 359.4 C at 760 mmHg
Flash point: 162.4C
Foam stabilizer
As a surfactant, calcium stearate not only has little effect on the strength of cement-based materials, but also can make the air bubbles insoluble in water, which can improve the elasticity and mechanical strength of the cement foam liquid film, so that the cement liquid film can be better withstand external forces without breaking.
While calcium stearate is used as a foam stabilizer, it is also a water repellent. It forms hydrophobic substances with the hydroxyl groups in the cement paste, and arranges them directional on the capillary walls of the cement paste, hindering the movement of water and entering the pores. The pore surface of the foamed concrete is gradually wrapped by the hydrophobic agent, forming a A layer of protective film, the permeability of the pores is continuously reduced, so that the water absorption rate is significantly reduced.
Waterproofing agent
The waterproof mechanism of calcium stearate is mainly that when the foamed cement solid powder is mixed with water, the cement particles begin to undergo hydration reaction. At this time, calcium stearate will be adsorbed on the surface of the cement particles and at the interface between the air bubbles and the cement slurry. , with the progress of the hydration reaction of the cementitious material, the cement paste gradually hardens, and finally the presence of calcium stearate makes the surface of the cells and the void surface of the cement stone change from hydrophilic to hydrophobic, preventing the intrusion of water, thus The water absorption rate of cement is significantly reduced.
