( Rice Husk Ash )
RHA is a good super-pozzolans . RHA can be used in a big way to make special concrete mixes There is a growing demand for fine amorphous silica in the production of special cement and concrete mixes ,high performance concrete ,high strength, low permeability concrete, for use in bridges, marine environments , nuclear power plants etc.
USE OF RICE HUSK ASH
For Strength :
Adding RHA to the concrete mix even in low replacement will dramatically enhance the workability , strength and impermeability of concrete mixes , while making the concrete durable to chemical attacks , abrasion and reinforcement corrosion , increasing the compressive strength by 10% - 20 % .
For water proofing :
RHA has excellent water resistance ( impermeability ) properties and is used in waterproofing compounds to give amazing results. it reduces the water penetration by as much as 60 % .
For Better Concrete in Marine environment:
Adding RHA to concrete and paints helps to reduce the chloride ion penetration by as much as 50 % into the structure , thus improving life of the building.
For Lower heat of Hydration :
Adding RHA to concrete lowers the heat of hydration by as much as 30 % and prevents formation of cracks during casting .
RHA acts as a very good insulator . RHA is also used for insulation of molten metal in tundish and ladle in slab caster .
The temperature of molten metal in the ladle is around 1400 degrees centigrade and above . When this metal flows from ladle to tundish , the temperature drops to around 1250 degrees . This reduction in temperature leads to choking and causes breakdown in the slab caster.
When this RHA is spread as a coating over the molten metal in the tundish and in ladle , it acts as a very good insulator and the temperature is maintained and does not cool down quickly , hence reducing the breakdown time of the casting.
Rice Husk is burnt in controlled temperatures which is below 700 degrees centigrade . This ash generated is amorphous in nature . The transformation of this amorphous state to crystalline state takes place if the ash is exposed to high temperatures of above 850 degrees centigrade .
Green Concrete : Green Concrete as the name suggests is eco friendly and saves the environment by using waste products generated by industries in various forms like rice husk ash ,micro silicaetc. to make resource-saving concrete structures .Use of green concrete helps in saving energy,emissions, waste water Green concrete is very often also cheap to produce as it uses waste products directly as a partial substitute for cement,thus saving energy consumption in production of per unit of cement . Over and above all green concrete has greater strength and durability than the normal concrete.
High Performance Concrete : Also known as HPC , the name given to mixtures with high workability and very high early strengthsand long term durability .