ZEMCH 2015 - International Conference Proceedings | Page 784
20
20
PC_1
PC_2
PC_3
18
16
14
14
12
12
LOAD (kN)
LOAD (kN)
16
10
8
10
8
6
6
4
4
2
2
0
0
0
500
1000
1500
2000
2500
ISFC_1
ISFC_2
ISFC_3
18
3000
CTOD (mm)
a)
0
500
1000
1500
CTOD (mm)
2000
2500
3000
b)
20
RSFC_1
RSFC_2
RSFC_3
18
16
LOAD (kN)
14
12
10
8
6
4
2
0
0
500
1000
1500
2000
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3000
c)
CTOD (mm)
Figure 8: Applied Load vs. CTOD for: a) Plain concrete; b) ISFC; c) RSFC
The main difference between plain concrete and reinforced concrete flexural behaviour is generally characterized by a residual strength in the post-cracking stage with a significant improvement of the material toughness. Thus, confirming the outcome of several studies on the same
topic (Holschemacher et al. 2010; Buratti et al. 2011; Olivito et al. 2010; Uygunoğlu 2011).
Conclusions
The experimental tests herein discussed are part of a larger experimental campaign, addressed to
evaluate the effectiveness of recycled steel fibres from waste tires in concrete. On the basis of the
experimental results discussed in this paper, the following remarks can be made:
• Although there is only a slight increase in compressive strength, the principal effect of the fibres is to bridge the cracks developing into the matrix, increasing the ductility of the concrete
element;
• The post-cracking behaviour of RSFC is comparable with that of ISFRC. Both types of reinforced concrete exhibit better properties than the unreinforced concrete. As expected, considering reinforced concrete, the softening branch of the curve was significantly modified, both
in terms of ultimate strain, residual stress and stress gradient;
• The reinforced specimens have shown good energy absorption and good residual strength
after cracking. This is the main effect of the presence of the fibres across the cracks, which
contribute in delaying the complete collapse of the specimens or avoiding premature failure
caused by possible not homogeneity of materials;
• RSFC evidenced a significant scatter in the post-cracking stage under flexural tests: probably,
the different distribution of the fibres at the broken section governs the behaviour of the specimens.
• The results confirmed that recycled steel fibres from scrap tires could be an alternative as reinforcement of concrete matrix. However, there is still the need of further research work to
widen the experimental database and to better characterize the proposed material.
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ZEMCH 2015 | International Conference | Bari - Lecce, Italy