Abstract
Energy efficient and cost saving cement alternatives have
been identified for use by researchers without compromising
standards. The utilization of artificial pozzolanas as Cementitious
Materials (CMs) in cement chemistry and engineering is widely
known. Nevertheless, there is continual search for optional and
greener substitutes. The use of Rice Husk Ash (RHA) as CM was
studied. The abundance of RHA and the need for low cost shelter
triggered this investigation looking into chemical composition of the
generated ash and the compressive strength of the concrete type
produced by partly replacing Ordinary Portland Cement (OPC) with
RHA under short hydration periods. 60 cubes of 300 mm dimensions
were cast with cement substituted by RHA ranging from 0-40%,
adopting 28 day targeted strength of 25 MPa as control. Specimens
hydrated at relative humidity (RH) of 95-100% and temperature (T)
of 22-25
0
C in a chamber for 7, 14, 21, and 28 days. Results revealed
trends of strength gain and reduced density with increase in RHA.
The 28 day density and strength of the control specimen was 2465
kg/m3 and 28.6 MPa while the 10% RHA sample (i.e. best replaced
matrix) had 2398 kg/m3 and 26.0 MPa respectively. The strength of
10% RHA/OPC product (26.0 MPa) was slightly higher than the
adopted strength (25 N/mm2) at 28 days. This can serve as cost
saving means in rural housing schemes with less structural demands.