The Portland cement production attributed about five per cent of the global CO2 emission. In addition to the issued of carbon dioxide emissions continues demand on cement production lead to depletion of nature raw materials. While at the same time, the growth in the world population and resultant increase in demand on food production, produced more waste as a by-product. Steady increase in the world population led to and increase industrial and agricultural waste adding another environment pollution problem to face. All of these reasons forced researchers to look for alternative materials for possible use instead of cement in construction as a first goal. Minimizing CO2 emissions by firstly reduce cement production and secondly pollution of dumping industrial and agricultural waste were the objective. In addressing these objectives, the investigations led researchers to use the pozzolanic materials, which are by-product materials produced as an industrial waste or agricultural by-product. These industry waste materials such as fly ash, slag, silica fume and agricultural waste like rice husk ash are very rich with silica content and because of the pozzolanic behaviour can be used as cementitious materials. Alternatively, these by-product materials would be considered as another waste problem and would need large tracts of land to dump the waste, therefore, it is considered as another source of pollution.
The effect of chemical composition, physical properties and pozzolana activity of RHA has been studied. However RHA properties had a different impact on the ordinary Portland cement concrete performance. This contradiction in performance of RHA properties offers a challenge for investigation. To appropriately utilise RHA in OPC concrete, it is important to understand, in depth, the impact of the properties of this renewable pozzolanic material on the properties of fresh and hardened concrete.
Funder: Ministry of higher education and scientific research/Iraq