Use of Industrial Waste as Aggregate: Properties of Concrete - Recycled Aggregate in Concrete - page 145

Fig. 4.23 Compressive strength of various types of concrete at three different curing conditions:
a at 23 C in immersion; b at 23 C in 50 % humidity; c at 23 C with sealed specimens (Collins
and Sanjayan 1999 )
curing period was higher than that of AAS with BFS aggregates. On the other
hand, the compressive strength of AAS with BFS aggregates was higher than that
of NA AAS at the whole curing period when both were cured at 23 C with 50 %
room humidity due to internal curing effect, where the moisture present in BFS
aggregates came out at low humidity conditions (Fig. 4.23 ).
Etxeberria et al. ( 2010 ) observed lower modulus of elasticity and splitting
tensile strength for concrete with BFS aggregates than for conventional concrete at
two different ranges of w/c values. These values further decreased as the content of
BFS aggregate in concrete increased. Lower modulus of elasticity was reported for
BFS-aggregates concrete in comparison to conventional concrete in Haque et al.s'
( 1995 ) study too. On the other hand, in comparison to conventional concrete, about
8-10 % higher splitting tensile strength and higher elastic modulus were recorded
for concrete with BFS coarse aggregates prepared at various w/c ratios.
Ashby ( 1996 ) observed similar elastic modulus of elasticity but marginally
higher Poisson's ratio for concrete with air-cooled slag aggregates than for natural
gravel aggregates concrete. The specific creep for grade 20 concrete with air-
cooled aggregates was lesser but for grade 40 concrete it was similar to that of the
natural gravel concrete.
Yüksel et al. ( 2007 ) observed higher abrasion resistance of concrete with BFS
as partial replacement of fine aggregates. In this study, the fine aggregates were
replaced by BFS aggregates up to a replacement level of 50 % (by weight).
Maximum abrasion resistance was observed when 10 % of fine aggregates were
replaced by BFS aggregates.