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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 6
Pull Off test to evaluate the compressive strength of concrete: an alternative to Brazilian standard techniques
correlation with the compressive strength of the two tests standard-
ized by the Brazilian Association of Technical Standards (ABNT).
3. Experimental procedure
The experimental procedure of this research investigated the ef-
fectiveness of NDT as a tool for assessment of concrete strength
compared to the results obtained by simple compression of pris-
matic and cylindrical specimens. For this, the rebound hammer
and ultrasound tests were selected, standard in Brazil and the Pull
Off test, presented in this paper as an alternative to popular tests
for structures evaluation.
3.1 Materials
The cement used was a CP II F-32. The chemical composition and
the physical and mechanical characterization of the cement are
shown in Table 1.
Fine aggregate was natural river sand with 2.23 fineness modulus.
Coarse aggregate is of a limestone with 25.0 mm nominal maxi-
mum size. Figures 4 and 5 show the size distribution curves of
these aggregates.
3.2 Description of study variables
Initially, a proportion of concrete mixtures with three different water/
cement ratios (0.43, 0.5 and 0.59) was used. Using these concrete
mixtures prismatic and cylindrical specimens were prepared for sim-
ple compression, rebound hammer and ultrasound tests. For the Pull
Off test one concrete slab for each water/cement ratio was molded.
The tests were conducted in the Structures and Materials Laboratory,
located on the campus of the Federal University of Paraná.
Figure 4 – Particle size distribution of the fine aggregate
Figure 5 – Particle size distribution of the coarse aggregate