Microsilica as a Pozzolan

• Microsilica is an excellent pozzolanic material because of its fine texture and high silicon content. A pozzolan can be combined with calcium hydroxide to create a cementitious, or binding and hardening, product. Pozzolans are frequently used in combination with common cements, such as Portland cement, to prolong the life of the cement and to reduce its overall cost.
  
  

Hydraulic vs. Nonhydraulic

• There are two major types of cement: hydraulic and nonhydraulic. Hydraulic cements will harden in wet or dry conditions, and maintain their structural integrity whether they are submerged in water or left in the desert. Nonhydraulic cements, such as gypsum plaster and lime, must be kept dry to maintain their usefulness as a building material and reinforcement. Microsilica is used in hydraulic cements such as Portland cement, the most commonly used cement worldwide that forms the main ingredient of grout, mortar, stucco and concrete.
  
  

Application

• Microsilica, when added to a cement mixture, strengthens the cement and reduces its porosity. Microsilica also improves the abrasion resistance, bond strength and compressive strength of cement. The compressive strength of cement is its ability to withstand force that pushes against it from opposite sides. Its bond strength is measured by the degree to which the cement's atoms are linked to one another. Adding microsilica to cement mixtures also reduces the viscosity of the cement, so that it can more easily be shaped and spread before hardening.
  
  

Similar Products

• Microsilica has two major potential alternatives that can be used to achieve the same desired effect in cementitious mixtures. Kaolinite is a layered silicate clay mineral, also known as white clay, china clay or kaolin. Its name in English is derived from its Chinese name, "High Hill," from the Jiangxi Province where it was discovered. Rice husk ash is the ash produced after burning rice hulls, and this ash is also high in silica. Because it is even cheaper to produce than microsilica, rice husk ash is being examined as a potentially economical alternative for use in cementitious products.