EFFECTS OF MICROWAVE INCINERATED RICE HUSK ASH (MIRHA) ON HYDRATION CHARACTERISTIC AND MECAHNICAL PROPERTIES OF FOAMED CONCRETE

The better a material is understood, the better it can be utilized. With cementbased
material such as foamed concrete (FC), knowledge of the fundamental cement
hydration reactions and resultant product will facilitate design, behaviour prediction,
and improved performance. Water is an integral part of all cement-based materials. It
contributes to the mixing and placing ability of the material, enables the hydration
process, and influences material property development. As such, it is worthy of
comprehensive study, for one will never fully understand cement-based material if
one does not have a good grasp of the role of water in them. The study of water in
FC with Microwave Incinerated Rice Husk Ash (MIRHA) as pozzolanic material is
particularly interesting, for which information about the water content can be used to
understand the behaviours of the product. This study was mainly focused to
investigate the role MIRHA on the non-evaporable water content in the FC
The mix proportion of the MIRHA FC was designed using the Taguchi method
with L16 orthogonal array with five parameters, namely, MIRHA contents, water
cementitious ratio (w/c), sand cement ratio (s/c), superplasticizer (SP) content, and
foam content. The mixtures were tested, both in fresh and hardened states to meet
technical requirement of FC. Analysis of the characteristics of concretes, namely its
compressive strength, non-evaporable water (wn) by oven dry/furnace ignition
(OD/FI), non-evaporable water (wn) by Thermogravimetry (TGA), dry density and
porosity were conducted.
The results showed that MIRHA could facilitate enhancement in FC hydration
with the evidence from wn OD/FI and TGA, Calcium Hydroxide (CH) contents and
change in non-evaporable water content. The degree of hydration of MIRHA FC was
predicted using a model that employed non-evaporable water technique.