EXPERIMENTAL INVESTIGATION OF SESAME STRAW ASH BLENDED WITH RICE HUSK ASH ON FLEXURAL STRENGTH AND DURABILITY OF CONCRETE

Abstract

This study investigates the effect of sesame straw ash (SSA) blended with rice husk ash (RHA) as a substitute for
cement on the flexural strength and durability of concrete. The investigation involves the replacement of cement
with blended ashes of sesame straw and rice husk in an increment of 0, 10, 15, 20, 25, and 30 %. The flexural test
was done on SSA-RHA concrete beams at 3, 7, 28, 56, and 90 days of curing in the water while the compressive
strength of SSA-RHA-concrete exposed to 5 % Conc. of H2SO4 was performed after 28 days in water at 3, 7 and
28 days of curing in the solution of 5 % Conc. of H2SO4. The X-ray fluorescence (XRF) test was carried out on
SSA and RHA. The result of the XRF test carried out on SSA and RHA shows that SSA had a CaO content of
45.42 % and RHA had the sum of Al2O3, SiO2, and Fe2O3 of RHA as 84.22 %. The workability of SSA-RHA-
concrete decreases as the percentage of SSA-RHA content increases. The flexural strength of SSA-RHA concrete
decreases and increases as the percentage of SSA-RHA and curing period increase respectively. However, the
retained compressive strength of SSA-RHA-concrete cured in H2SO4 solution decreases as the percentage addition
of SSA-RHA and curing increase. On the other hand, the water absorption increases with an increase in the
percentage of SSA-RHA content. The density of concrete decreased as the curing period in H2SO4 solution
increased. However, most of the densities of SSA-RHA-concrete fall within the limits of 2200 kg/m3 to 2600
kg/m3. It was concluded that SSA and RHA blend can be used as supplementary cementitious materials in the
production of concrete.