The use
of saturated surface dry RCA tended to give a higher workability
than that with LS. Because of the RCA particles contain a larger
volume of pore and water at saturated surface dry condition than
that of LS particles. The water inside RCA particles was available and
improved the workability of the mixes (Poon et al., 2004). The
report of Mefteh et al. (2013) showed that the use of RCA in pre-wetting
and saturated surface dry conditions improved the concrete
workability. In addition, at the same liquid to ash ratio, the use
of high NH concentration gave geopolymer concrete with low
slump flow. This was due to the increase in NH concentration
resulted in leaching of more silica and alumina and thus increase
the geopolymerization and the stiffness of the system
(Chindaprasirt et al., 2009).