Including moderate amounts of cementitious materials and fine
fillers in cement mixtures decreases the coarse aggregate volume and
reduces the risk of blockage, while simultaneously increasing the
segregation resistance and reducing the costs associated with high
volumes of Portland cement and superplasticizer [3]. Rice husk is a
major agricultural byproduct that is available in many parts of the world.
When rice husk is burnt at temperatures below 700 ºC, rice husk ash
(RHA) with a cellular microstructure is produced. RHA contains a high
amount of non-crystalline or amorphous silica. Therefore, RHA is a
pozzolanthat can be used as a supplementary cementitious material [4].
Arecent study found that residual ‘as received’ (unground) RHA can be
used in normal-strength concrete, if an appropriate sequence for
incorporating the component materials is adopted during the cementmixing process. An adequate RHA particle size can be obtained by
mixing RHA with coarse aggregates for a specified period [5].