A valuable green resource with the great potential what is called the rice husk ash. Rice husk ash can be used as supplementary cementitious material that can be added to concrete instead of cement to increase the strength and durability of the cement. The research so far indicates that optimum durability is obtained when seven to ten percent by weight of cement is replaced by rha. RHA are very close to micro silica fumes. If we try to define the properties of rice husk ash and rice husk ash micro- how are they in groups the concrete it’s very well known that OPC reacts with water to form two products calcium silicate hydrate and calcium hydroxide. This calcium silicate hydrates gives strength and durability to the concrete whereas calcium hydroxide it causes a negative effect in the concrete it’s it reacts with the co2 to causing a fluorescence leaving the concrete vulnerable to sulphate. Rice husk is added to the cement to increase the strength of the concrete and two to create green concrete wherein RHA is used as a substitute of cement a detailed study carried out , compared the strength and durability of concrete something supplemented with micro silica. Silica fumes to that of concrete supplemented with rha the numbers which are going to come forward no way prove that rha is a superior product than micro silica silica fumes if you can find that this is M 70 grade concrete by adding 10% rha beginning a strength increase of about 7% this graph shows the strength over a period of 90 days the maximum strength gain is in between 56 and 90 days by use of RHA in concrete quarter in permeability can be increased by up to 60% same with the decrease and chlorite attacks to a modern 60% addition of RHA to concrete decreases the heat of hydration to about 20 percent .
Silica An Important substance
All over the world, in every part of our lives, we have silica in many forms be it in the toothpaste that you use, electronics, fiber optics etc. Silica is used to polish silicon wafers to make them very flat. It’s about tens of thousands of tons a year process. The process of silicon metal, done by taking silica with carbon and treating it in an electric arc furnace at three thousand degrees Fahrenheit. By producing silica that way you also of course reduce carbon dioxide. It’s a very expensive process; obviously it would be nice if you could figure out how to use other forms of silica to produce silicon containing compounds without ever having to go to three thousand degrees. You can dissolve silica in antifreeze with a little bit of base which we can recycle and then after we dissolve it with the antifreeze, we replaced the anti- freeze with ethanol that allows us to distill it to a high purity. 99.9999% purity, so it can be used anywhere. Now we can use not only sand but Ag-waste in the form of rice hull ash. The rice plant takes silica out of the ground and it puts it in the husk and it puts it in the stock to reinforce them to make them stronger. Plants don’t pick up heavy metals so the silica that’s contained in any plant is relatively pure. A group of people have learned to burn their rice hulls for their fuel value. The byproduct is a silica rich ash. Everywhere that they produce rice they produce rice hull ash.
