Basic HTML Version
714
IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
Mechanical behavior analysis of small-scale modeling of ceramic block masonry structures –
Geometries effect
T�ble � � Res�lts of compression strength of prisms
Block
Prism
Type
PRISM
PRISM
PRISM
MORTAR I
MORTAR II
MORTAR I
f A
net.
f A
gross
f /f
p b
f A
net.
f A
gross
f /f
p b
f A
net.
f A
gross
f /f
p b
f
p
f
p
f
p
20,48
10,56
0,36
24,50
12,64
0,43
24,27
12,52
0,43
A
s.d
s.d
s.d
2,10
4,30
1,29
c.v
c.v
c.v
10,30
17,57
5,32
f
p
f
p
f
p
23,64
13,61
0,42
26,59
15,31
0,47
25,98
14,96
0,46
B
s.d
s.d
s.d
2,05
2,83
1,03
c.v
c.v
c.v
8,67
10,65
3,96
f
p
f
p
f
p
23,04
11,18
0,37
26,03
12,64
0,41
28,59
13,88
0,45
C
s.d
s.d
s.d
3,98
0,96
4,30
c.v
c.v
c.v
17,30
7,61
15,00
f
p
f
p
f
p
20,30
11,67
0,35
22,99
13,22
0,39
26,25
14,88
0,45
D s.d
s.d
s.d
1,42
1,74
3,34
c.v
c.v
c.v
7,00
7,56
12,70
Where: f is the prism strength (MPa); f /f is efficiency factor between prism strength in relation to the block; s.d. is the standard
p
p b
deviation (MPa); c.v is the coeficiente of variation (%); f A is the strength in the net area; f A is the strength in the gross area.
net
gross
The experimental results of compression tests of stack and run-
ning bond prisms with mortar types I and II are presented in Table
08 along with the standard deviations and coefficients of variation.
The compressive strength results for prisms and blocks were ob-
tained
for both the net and gross areas (ES 772-1 [18]). There
were no significant differences in the compressive strength results
for prisms using the different block types A, B, C and D. The small
differences in the strength values are likely due to the superposi-
tion of the face-shell and the cross webs of the blocks for the two
types of prisms. Table 08 presents the efficiency factor between
the compressive strength of prisms and blocks (
f
p
/f
b
). It was ob-
served that there was a reduction in the compressive strength be-
tween prisms and blocks of approximately 55% to 65%. The failure
mode of prisms were similar to those obtained by MENDES [8]
who observed a failure caused by crushing of the bedding mortar
joint and the splitting of the surfaces between blocks and mortar.
The circles in Figure 17 depict the failure modes of prisms. The
tests showed that scale-reduced prisms had failure modes similar
to those obtained for full-scale prisms.
For each type of block and mortar, three walls were built and test-
ed. The blocks were wetted before bedding so that water would
not be removed from the mortar, making it available to hydrate
the cement. The blocks at the top and bottom of the walls were
capped with the cement paste and sand mixture described above
before testing. Walls were tested 28 days after construction, and
remained in the laboratory environment between construction and
testing. Table 09 presents the compressive strength results for
walls with different block geometries and two types of mortar along
with the standard deviations and coefficients of variation measured
on both the net and gross areas. Figure 19 presents the individual
compressive strength results for blocks, mortars, prisms and walls.
Figure �� � F�ilure mode of
three-block prism