Doha Refractory Bricks Suppliers and Manufacturers

Microsilica (silica fume) is a by-product of silicon metal or ferrosilicon industries, is an amorphous silicon dioxide SiO2. This product reacts chemically with the calcium hydroxide in the cement paste which yields a calcium silicate hydrate gel that significantly enhances strength and durability. The super fine microsilica fills the voids between cement particles creating a very dense, less permeable concrete. Physical characteristics: Color: gray or gray white powder Bulk density: 320-700 kg/m3 Chemical composition: Items SiO2 Al2O3 Fe2O3 MgO CaO Na2O Moisture Content 75-98% 1.0-0.2% 0.9-0.3% 0.7-0.1% 0.3-0.1% 1.3-0.2% Fineness: the fineness of the silica fume is less than 1 1/4m, and the average particle size is 0.1 0.3 1/4m, and the specific surface area is 20 - 28 m2/g. The fineness and specific surface area are about 80-100 times of cement and 50-70 times of fly ash. Maxtech Micro Silica supplies will be as per QCS 2014 (ASTM C1240): SiO2: >/= 92% LOI:

Fly ash is a finely divided residue made from the combustion of pulverized coal that can be used to increase concrete durability and workability, while reducing permeability. As fly ash contains aluminous and siliceous components, it may form cement when mixed with water if the calcium content of the fly ash is high enough. Similarly, mixing fly ash with lime and water can create a substance similar to Portland cement. Fly ash can be separated into two main types, known as: Class F Class F fly ash contains particles covered in a type of melted glass allowing it to reduce the risk of concrete expansion and increase resistance to sulfates and alkali-aggregate reactions. Class C Class C fly ash contains a higher percentage of calcium oxide, making it more effective in strengthening structural concrete. Applications & Benefits of Fly Ash: Fly ash is used in commercial and industrial sectors for improving the durability and workability of concrete mixes. Fly ash is also used as filler in paints, adhesives, and metal and plastic composites. It's commonly used as structural fill for road construction and fly ash can be used to make bricks, ceramic tiles, plaster, Portland cement, and ready-mix cement.