MORPHOLOGICAL AND MECHANICAL CHARACTERIS. pdf

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MORPHOLOGICAL AND MECHANICAL
CHARACTERISTICS OF MASONRIES AND
MATERIAL PROPERTIES
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4 AUTHORS, INCLUDING:
Luigia Ada Binda
Politecnico di Milano
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Available from: Luigia Ada Binda
Retrieved on: 05 February 2016

MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF

MASONRIES AND MATERIAL PROPERTIES
L. Binda, G. Baronio, G. Mirabella Roberti, D. Penazzi

1. SURVEY ON TEXTURE AND SECTIONS OF SOME MASONRY WALLS
Eight buildings were the object of the survey, including the two chosen as case-study for
multidisciplinary complete research within the Catania Project 1998, thanks to the
collaboration between the GNDT Group and the local Authorities.
Since it was impossible to inspect the inside of the walls of these two buildings due to the fact
that rendering could not be destroyed, only the texture and inside of the walls of the other six
buildings were surveyed.
1.1 Texture of the masonry walls
The complete survey was possible or six sites thanks to the fact that some ruins were
available or works were carried out for repair and restoration of the some buildings. Sixteen
sections (Table 1.1) were surveyed and studied first of all according to the bonding technique
and to the stone shape and dimensions (Binda 1999, Binda et al., 1999b).
Name
Location
Ca3
Via Vittorio Emanuele
Ca4

Via Consolazione
Ca5
Via Consolazione
Ca6
Church S. Nicolò
Ca7
Province Building
Ca8
Via Dusmat
Table 1.1 Surveyed walls

Studied walls
Ca3p1, Ca3p2, Ca3p3
Ca4p1, Ca4p2
Ca5p1, Ca5p2
Ca6p1
Ca7p1, Ca7p2, Ca7p3, Ca7p4, Ca7p5, Ca7p6
Ca8p1, Ca8p2

100

90
80
70
60
50
40
30
20
10
0

f (%)

f (%)

Most frequently the stones are simply boasted, but often are more or less regular ashlars.
A large use has been found of clay elements, such as bricks in the so called “intosto”
masonries (see Fig. 1.2a) or roof tiles used as wedges in the external masonry leaves. The
mortar joints are irregular or quasi-regular (sub-horizontal) (Fig. 1.1a). Fig.1.1b shows the
overall percentual distribution of mortar, stone and voids over the surveyed sections.

corsi irreg.
Irregular

corsi sub.
Quasi-regular

Fig. 1.1a Distribution of horizontal courses

100
90
80
70
60
50
40
30
20
10
0

% Stone
p ietra

% m a lta

Mortar

% vuoti

Voids

Fig. 1.1b Material percentage

1.2 Cross-sections of the walls
The surveyed sections were sixteen, but one was discarded due to the non-typical
dimension, being 1300mm thick. In fact the most diffused wall type seems to be a double-leaf

masonry with a fairly good connection between the two leaves and average thickness of 65cm
(Table 1.2).
Five cases belong to the so called “intosto” typology with an average thickness of 35cm.

The “intosto” masonries were used typically during the last century in Sicily as partitioning
walls; the horizontal courses were made alternatively with bricks and volcanic basalt units
defined locally as “cannarozzone da intosta”. The ashlars were tooled and fairly regular with a
height of 25-30cm.
Name

Elements
Stone %
Mortar %
Ca3s1
62,70
29,44
Ca3s2
64,04
35,58
Ca3s3
x
58,66
39,23
Ca4s1

x
58,66
39,23
Ca4s2
x
67,58
32,23
Ca5s1
x
69,77
27,75
Ca5s2
x
61,24
37,91
Ca7s1
x
39,82
58,19
Ca7s2

x
n.r.
n.r.
Ca7s3
x
54,80
43,26
Ca7s4
x
65,52
33,19
Ca7s5
x
60,22
33,86
Ca7s6
x
65,15
30,22
Ca8s1

x
41,46
56,30
Ca8s2
x
74,81
24,05
Table 1.2 Geometrical parameters of the surveyed sections
1

No. of leaves
2
3
x
x

Voids %
7,86
0,38
2,11

2,11
0,19
2,48
0,85
1,99
n.r.
1,76
1,29
5,92
0,63
2,24
1,14

Three walls appeared to be three-leaf walls but in two of them one extenal leaf had been
built in bricks and added after the construction of the wall. The data concerning the surveyed
sections are reported in Table 1.2. From the same table it can be seen that the void percentage
is usually very low (