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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
E. RIZZATTI | H. R. ROMAN
|
G. MOHAMAD | E.Y. NAKANISHI
Table � � Tensile strength by diametral compression
Block Type
Tensile strength by diametral
compression (MPa)
Mean
1,81
A
s.d
0,23
c.v (%)
12,89
Mean
1,57
B
s.d
0,16
c.v (%)
10,05
Mean
1,67
C
s.d
0,11
c.v (%)
6,41
Mean
1,80
D
s.d
0,17
c.v (%)
9,30
- s.d is the standard deviation and c.v (%) is the coefficient of variation in percentage.
4.3 Mechanical characterization of prisms and walls
Five stack bond prisms that were three blocks high were built with
each of the two types of mortar (I and II) and five running bond
prisms with an intermediate row composed of two half-blocks and
a vertical joint were built only with mortar type I. The three-block
height was selected because of the effect of confinement stress
produced by the plate so that the intermediate block did not de-
velop shear stress. The prisms have a full mortar bedding (face
shell and cross webs) and were built on a levelled granite table
and covered with a plastic with oil. The thickness of the mortar
joint remained constant on the order of 3 ± 0.1 mm. Levelling
was maintained during prism construction while plummeting was
maintained during construction of masonry walls. The prisms
were tested 28 days after construction. Before the compression
tests the prisms were capped with a mixture of 70% cement paste
and 30% sand retained on 0.15 mm sieves. Prisms and walls
were tested using a servo-controlled machine (SHIMADZU, se-
ries UH) with a 200 ton capacity, at a loading rate of 0.05 ± 0.01
MPa/s. Table 07 shows the compression strength results for six
mortar type I and II specimens.
Ta��e � � �es��ts of mortar compression strength
BLOCK
The average compressive strength
of mortar I (MPa)
The average compressive strength
of mortar II (MPa)
A
3,08
5,21
B
3,17
5,53
C
3,43
5,46
D
2,56
5,15
f
mortar
f
mortar
Figure �� � �o��ressive strength
on blocks in the net and gross area