Strength Property of Laterite Blocks Made with Different Pozzolanic Materials

Abstract

The need for alternative building materials to reduce cost and other
environmental issues necessitated this work with locally available
laterite, saw dust ash (SDA) and rice husk ash (RHA) obtained from
agricultural and plant wastes. A total of 216 hollow blocks of size
450mm x 225mm × 150mm were produced using a mix ratio of 1:6
with water cement ratio of 1.0. SDA and RHA were used separately
and in equal proportions to partially replace Ordinary Portland
Cement (OPC) using percentage replacement levels of 0%, 5%, 10%,
15%, 20%, and 25%. The blocks were cured for 7, 14, 28 and 60 days
and the compressive strength obtained at these ages. The results gave
an optimum percentage replacement at 10% with equal proportions
of SDA and RHA with compressive strength values of 2.29N/mm2
,
2.34N/mm2
, 2.39N/mm2
, 3.09N/mm2 at curing ages of 7, 14, 28 and
60 days respectively. When considered separately, SDA with OPC
gave a higher strength value of 2.31N/mm2 at a curing age of 28 days
than RHA with OPC which gave a strength of 1.93N/mm2
. The
variation of the strength with age is linear, showing that the strength
increases with curing age. The compressive strength values at these
specified points are greater than the recommended value by Nigerian
Building and Road Research Institute (NBRRI) and Nigerian
Industrial Standard (NIS).