Measurement of water absorption was conducted in accordance with BS 1881-
122:1983; ‘Method for Determination of Water Absorption’. The cores were kept in
an oven for 72 h at 105 ± 5 C followed by subsequent cooling for 24 h in dry airtight
vessels. At the end of drying and cooling processes as described in the standard
specimens were immersed in water for 30 ± 0.5 min at 20 ± 1 C and then
weighed. Average water absorption of three cored specimens expressed as a percentage
of dry samples is considered as the water absorbed in each particular batch.