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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
R. R. F. SANTOS | D. R. C. OLIVEIRA
alkaline concrete with no carbonation).
To determine the mechanical properties of concrete testimony
were extracted from the structural elements by using a cutting
machine with rotary diamond crown shown in Figure 13. A total
of five concrete testimonies, two from the abutments, two from
the slab and two beam from the stringer. The testimonies that
had flaws in their end faces, due to the extraction process were
rectified with the aid of a circular saw, resulting in a final length
of 200 mm, as shown in Figure 14. Regarding the tests to de-
termine the modulus of elasticity and compressive strength of
concrete, the testimonies were tested following the recommen-
dations of NBR 8522 : 2003 [7] and NBR 5739 : 1994 [8], where
the first recommended to be realized three cycles of loading
and unloading with peaks corresponding to 30% of the failure
stress (fc) and 0.5 MPa . For this a servo-controlled machine
model PC-200CS, manufacturer EMIC, was used. Tests were
then performed with constant load speed rate of 0.25 MPa/s.
After the cycles of loading and unloading, a loading was applied
progressively until failure by crushing of the testimony. In addi-
tion to the strain sensor type “clip gauge”, still from the manufac-
turer EMIC, two strain gages acquired from the company Excel
Sensors Ltd., Model PA-06-201BA-120L, were installed at half
height of the testimony and diametrically opposed. Figure 15
shows details of the tests in the laboratory.
Figure �� � �estimony's length standardization and end surface regularization
Figure �� � �oncrete elasticity modulus determination