ENGINEERING PROPERTIES OF NORMAL CONCRETE GRADE 40 CONTAINING RICE HUSK ASH AT DIFFERENT GRINDING TIMES

ABSTRACT
The effect of rice husk ash produced at different grinding times on the engineering properties of
concrete was studied. Eight rice husk ashes representing different grinding times were used in
this investigation. Rice husk ash (RHA) was used to partially replace Portland cement Type I at
15% by weight of cementitious material. The compressive strength of concrete was designed to
achieve grade 40 N/mm2
 at 28 days. A superplasticizer was added to all mixes to provide
workability in the range of 110-120 mm. However, the water to cement ratio (w/c) of the
concrete was maintained at 0.49. Based on the results, the morphology of the rice husk ashes
was changed by grinding. Optimum grinding time appeared to be approximately 90 minutes,
during which time the compressive strength increased significantly. Generally, incorporation of
RHA at various grinding times can dramatically decrease or increase the engineering properties
of concrete.

Keywords: Grinding; Compressive strength; Superplasticizer; Concrete; Rice husk ash


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