Lightweight Aggregate Conrete
Waste Materials and Industrial By-Products
Ashes can be usefull in making building components !
Fly Ash
, an industrial waste arising from coal fired thermal power stations, currently poses a serious operational constraint and an environmental hazard. A 100 MW thermal power plant generates about 0.15 million tonnes of fly ash per annum when using coal with an ash content of 40%. Fly ash on the other hand, with both ceramic as well as pozollana properties, can be utilised usefully in the manufacture of bricks.The advantages are :
| Higher cold crushing strength |
| Low water absorption (13 to 15%) |
| Smooth and uniform size, requiring less quantity of cement mortar and no plaster |
| Lower bulk density levels minimise the resistance load on load bearing walls and thus save transportation costs |
| Saves on the use of cement mortar |
| Water and salinity resistant |
| Conserves agricultural land as no clay is required. |
In Asia however , past efforts have been made to incorporate RHA (rice husk ash ) which can be pozzolanic into brick elements for housing.
RHA can be an added component into cement sand bricks and could be seen as a potential low cost building element where rice husk can be found. There is abundant rice husk in Asia especially Malaysia and Thailand and every ton of padi can produce about 200kg of husk. Burning the husk into ash under controlled conditions and milling it slightly turns it into a powdery siliceous
Lightweight foamed blocks with RHA incorporated in the mix.
material that may be used as an aggregate in making bricks and blocks.If the ash is ground futher it may have some pozzolanic properties beneficial to the strength the product.Using RHA in bricks can also lower the weight of each component since the ash has a lower specific weight than sand.
