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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 1
M. K. EL DEBS | E.K. BELLUCIO
Figure 24 – Accumulated deformation results comparing applied roughness
A
B
able. A comparison between the roughness in Figure 24 was
made utilizing the deformation results found.
Considering the two loadings, there was a considerably higher
displacement on the pads with applied roughness. This result
is considered positive, confirming the importance of the use of
these pads.
5. Conclusions
From the analysis of the characterization tests, it is observed that:
a) the values of compressive strength of the material samples are
around 41MPa and of the reference mixture are 79.5 MPa. Thus,
there was a reduction of approximately 48%of the value of the modi-
fied mixture compared to the reference mixture. The value around
41MPa can be considered sufficient to be utilized in bearing pads.
b) for the tensile tests, the values found for the mixture with fibers
and the reference mixture are very close, on the order of 3.0
MPa, and this difference is not significant;
c) the modulus of elasticity of the material reached a 45% reduc-
tion in relation to the reference mixture, reaching 12.8 GPa;
d) in the concentrated load tests there was a better performance
of the mortar with the use of fibers. It was able to absorb 43%
more load than the reference mortar, and it allowed a displace-
ment of 96% more than the reference mortar.
e) the volumetric rate of the utilized fibers (2%) ensured the ap-
pearance of multiple cracks, which provides an acceptable
level of tenacity for the material.
From the bearing pads tests, it can be concluded that:
a) There was a significant difference between the mortar with the
use of fibers and roughness and the reference mortar;
b) In the monotonic loading tests it was observed a clear reduction of
the stiffness of the pad with the application of roughness on both
sides (RR). Comparing the LL and RR pads, the difference was
more than 30%, which indicates that the application of roughness
on both sides enables a significant reduction of this parameter;
c) Although the mixture with fibers presented a variation in the
results between the casts, these differences were not signifi-
cant for the RR roughness, that is, for the results of the mix-
ture PP12 and RR roughness, the values found were satisfac-
tory. For this mixture it was obtained 307MPa/mm, which is
37% less stiffness than that found for the reference mixture,
RR (490MPa/mm). Through the accumulated deformation it
was observed that the mixture PP12 has good deformation
capacity compared to the reference mixture, reaching 37%
more displacement than the reference mixture. It was also
observed that, with the increase of the loading cycles, the ma-
terial tends to have little elastic deformation. It was also con-
cluded that there was a better performance of the RR rough-
ness pads, and the displacement was 120% higher compared
to LL pads.
Based on all the results achieved, it can be conclude that the
PP12 mixture has a good performance with a reduction in stiffness
compared to previous results, and that the best performance oc-
curred with the application of roughness on both sides of the pad
as shown in the results of monotonic loading.
6. Acknowledgements
To FAPESP, for the financing of tests through the thematic project,
and CNPq for the scholarship of the author.
7. References
[01] BARBOZA, A.S.R.; SOARES, A.M.M. ; EL DEBS,
M.K. A new material to be used as bearing pad in
precast concrete connections. In Proc.
1st International Conference on Innovation in
Architecture, Engineering and Construction. eds.
Anumba, C.J. Egbu, C.; Thorpe, A., Loughborough,
UK, 2001, p. 81-91.