Civil Engineering Reference
In-Depth Information
Fig. 5.46 Effect of
transverse reinforcement in
concrete beams made with
NA only (HC) and by
replacing 25, 50 and 100 %
(HR25, HR50, HR100) of
coarse NA by RCA
5.3.6 Stress-Strain Relationship
The analysis of the stress-strain curve (SSC) of concrete can yield data such as
strength and toughness performance and therefore the evaluation of SSC is
essential for structural design of concrete. Several studies were done to evaluate
the SSC of concrete with CDW aggregate. The results from a few studies are
presented next.
Topçu and Guncan (
1995
) determined several factors such as toughness, plastic
energy capacity and elastic energy capacity from the stress-strain curves of con-
ventional concrete and concrete containing various amount of RCA as a
replacement of coarse NA. They observed a gradual decrease of toughness, plastic
and elastic energy capacities of the latter as the incorporation of RCA in concrete
increased.
Xiao et al. (
2006a
) observed a significant influence of RCA and replacement
ratio of coarse NA by RCA on the stress-strain curve of the resulting concrete
(Fig.
5.47
). The incorporation of RCA increases the peak strain but significantly
decreases the ductility of concrete i.e. ultimate strain. At 100 % replacement of
NA by RCA, the increase in the peak strain was 20 %. The higher peak strain was
due to the lower stiffness of RCA than that of NA. They also observed that the
Fig. 5.47 Stress (r)-strain (e) curves and ultimate strain of concrete with replacement of coarse
NA by coarse RCA (Xiao et al.
2006a
). a Stress-strain curve. b Ultimate strain
