Microwave Incinerated Rice Husk Ash(MIRHA) Concrete: A New Material In The Construction Industry

Rice covers 1% of the earth’s surface and is a primary source of food for billions of people. Globally, approximately 600 million tones of rice paddy are produced each year. On average 20% of the rice paddy is husk, giving an annual total production of 120 million tones. Rice Husk Ash (RHA) is produced by burning paddy husk and this activity affects the depletion of the ozone layer. It also causes damage to the land and the surrounding area where the RHA is being dumped. On the other hand when rice husk is burnt, the ash produced contains more than 80% pure silica and if properly prepared, it is in an active form which behaves very much like cement. Therefore burning procedure to obtain RHA that is highly reactive needs to be established so that it can be used as cement replacement.
The objective of this research is to establish a standard burning method to produce RHA with high content of amorphous silica. Burning the rice husk at high temperature will increase the SiO2 content but it is not suggested to burn rice husk above 800°C longer than one hour, because it tends to cause a sintering effect (coalescing of fine particles) and is indicated by a dramatic reduction in the specific surface. This paper presents a laboratory study on the effect of microwave incinerated rice husk ash (MIRHA) on the compressive strength of concrete. The performance of concrete mixes was determined by compressive strength test and the test results showed MIRHA concrete performed better than normal OPC concrete.