DURABILITY ASSESSMENT OF CONSOLIDATION
EFFECT ON SANDSTONE MONUMENTS
Marco Ludovico-Marques (IPS/ESTB)
Carlos Chastre (FCT/UNL)
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
DEGRADATION PATTERNS ON THE SANDSTONE
WALLS OF ST. LEONARD’S CHURCH
4 0 th I A H S W O R L D C O N G R ESS O N H O U SI N G S U S T A IN B LE H O U S IN G C O N S T R U C T IO N 1 1 – S u s ta in a b le R e h a b ili ta ti o n w it h E m e rg in g M a te ri a ls a n d S y s te m s
Five types of stone deterioration patterns (ICOMOS-ICS glossary):
Crack & deformation
Detachment
Features induced by material loss
Discoloration & deposit
S
t.
L
e
o
n
a
rd
's
M
e
d
ie
v
a
l Ch
u
rc
h
40th IAHS WORLD CONGRESS ON HOUSING
SUSTAINBLE HOUSING CONSTRUCTION
TS 11 – Sustainable Rehabilitation with Emerging Materials and Systems
INT
RO
DUCT
IO
N
41th IAHS WORLD CONGRESS ON HOUSING
EXPERIMENTAL PROGRAMME
• Four varieties of sandstones (A, B, C, M).
• Lithic arkose with carbonate cement according to Folk (1974). • The varieties C and
M
have around 20-25% carbonates and40-51% quartz.
MINERALOGICAL CHARACTERIZATION
PREPARATION OF SPECIMENS
• Samples were extracted from stone masonry walls close to
the built heritage.
• Similarity to the stones in the monuments: appearance, mineralogical composition, texture and structure.
• Specimen sizes: 5x5x5 [cm] and 5x5x10 [cm]
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
CONSOLIDATING PRODUCTS
. Treatment of stones were carried out in a laboratory
environment and in the monument
. Evaluation of the viability of two ethyl silicate consolidating products on stones:
Tegovakon V (TG) and Redur 420 (R)
. Selection criteria: commercial availability and reasonable costs.
. TG is produced by Goldschmidt in a single component (Before application: unit weight of 0.95±0.02 g/cm3 at 25ºC After application: dry residue of 34% after evaporation
of solvents at 20ºC and 60% of RH).
. R is manufactured by Promasil in a single component (Before application: unit weight of 0.83±0.02 g/cm3 After application: dry residue of 17% after evaporation of solvents at 20ºC and 60% of RH).
EXPERIMENTAL PROGRAMME
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
CONSOLIDATION PROCEDURES
. 5 cm-long cubic samples.
. Applications step by step by immersion and capillarity over all stone mass (Ludovico-Marques, 2008).
.The amounts of absorbed products were around 5% of mass content in variety M.
. Drying at at room temperature and RH of Laboratory (Civil Engineering Department of FCT-UNL).
. A dry residue of about 40% of TG and 25% of R after evaporation of solvents during 8 weeks.
. Capillarity procedure was followed on samples used to carry out drying tests. Capillarity height reached 2.5 cm and the
amounts of absorbed products were around 3% of mass content.
EXPERIMENTAL PROGRAMME
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
PROCEDURES FOR PHYSICAL TESTS
• Porosity and density on sandstone samples following the Recommendations of RILEM (1980) and EN1936 (1999).
• Four varieties samples exhibit similar values of porosity to the historical building stones, ranging from 3.6% (variety A) to 12.7% (variety C) and 18.5% (variety M).
• Pore size distribution of sandstone varieties M was
obtained by mercury intrusion porosimetry. Microporosity
settled as the percentage of pores radii lower than 7,5 μm
(Pellerin, 1980), is 75-81% in variety M.
• Drying tests were carried out on top face of sandstone cubic samples of variety M before and after treatments, following the Recommendations of NORMAL 29/88 (1991) and RILEM (1980) at laboratory environment of 20 ± 2 º C and 55 ± 10% of RH.
• RILEM (1980) water absorption under low pressure test procedure was carried out on prismatic and cubic sandstone samples. After consolidation treatments was only applied on cubic samples.
EXPERIMENTAL PROGRAMME
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
The uniaxial compression tests on the sandstones used a Seidner servo-controlled press, model 3000D:
• Load capacity up to 3000kN and a piston stroke of 50 mm.
• Tests carried out under axial displacement control at a rate
of 10 mm/s on cubic specimens of variety M.
EXPERIMENTAL PROGRAMME
PROCEDURES FOR MECHANICAL TESTS
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
• Crystallization tests by total immersion were carried out following RILEM V.1a, b, V.2 (1980) [6] and EN 12370 [10], replacing sodium sulphate solutions by sodium chloride solutions.
• Salt crystallization-dissolution ageing tests were carried out in an automatic ageing chamber prototype.
EXPERIMENTAL PROGRAMME
PROCEDURES FOR DURABILITY TESTS
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
PHYSICAL BEHAVIOUR
(DI)
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
n
0 5 10
0 500 1000 1500
M
o
is
tu
re
c
o
n
te
n
t
(%
)
M27TG, M42TG, M23TG, M26TG, M29TG, M6TG
t (h)
M103,106,104,105,107,108
0 1 2 3 4 5 6 7 8 9 10
0 500 1000 1500
t (h)
M
o
is
tu
re
c
o
n
te
n
t
(%
)
M103,106,104,105,107,108
Variety
Drying Index
Average ± SD (CV %)
M 0.10 ± 0.01 (9.80)
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
Consolidating product
Drying Index
Average ±SD (CV %)
TG
0.12 ± 0.01 (8.33)
R 0.11 ± 0.01 (9.09)
Minor increase
20% on TG
10% on R
PHYSICAL BEHAVIOUR
(DI)
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
PHYSICAL BEHAVIOUR
(k)
4 1 th IA H S W O R L D C O N G R ESS O N H O U SI N G U S T A IN A B ILI T Y A N D I N N O V A T IO N FO R T H E FU T U R E O S – E x p e ri m e n ta l R e s e a rc h o n B u ild in g R e h a b ili ta ti o n 0 1 2 3 4 5 6 7 8 9 10 0 1 0 1 2 3 4 5 6 7 8 9 10
0 10 20 30 40 50 60
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
PHYSICAL BEHAVIOUR
(k)
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
n
C
o
n
so
li
d
a
n
ts
Water absorption coefficient, k (kg/m2/√h)
Average ± SD (CV %)
NT 24.0 ± 1.6 (6.8)
TG 12.6 ± 1.0 (8.2)
R 20.9 ± 1.9 (8.8)
Significant decrease
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
DURABILITY ASSESSMENT BY SALT
CRYSTALLIZATION DISSOLUTION ARTIFICIAL
AGEING TESTS
After 60 salt cycles the average mass loss of sandstone samples is about 8%
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
n
0
2
4
6
8
10
12
14
16
18
20
0 5 10 15 20 25 30 35 40 45 50 55 60 Nc
D
m
/m
(%
)
M80 M69 M78 M95, M76
M99, M96, M93, M102, M100 M75, M90
M79, M101 M72, M81, M77 M91, M94
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
DURABILITY ASSESSMENT BY SALT
CRYSTALLIZATION DISSOLUTION ARTIFICIAL
AGEING TESTS
After 30 salt cycles reduction of 50%
After 60 salt cycles reduction higher on TG than NT After 70 salt cycles reduction on R less than NT
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
Clear increment of about 26% on TG and 10% on R treatments before salt artificial ageing tests
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
n
DURABILITY ASSESSMENT BY SALT
ANALYSIS OF RESULTS OF
EXPERIMENTAL PROGRAMME
• NT decreased about 56% during 60 cycles
• TG treated specimens have an average reduction of circa 75%
• R treated have a minor reduction of about 18% to the initial values of non treated specimens at 70th cycle
• Compressive strength data of NT specimens
extrapolated for more than 100 cycles decreased to about 30% of the initial values.
• At 115th cycle the compressive strength should be less
than 30% of its value before salt ageing, being higher than its value on R treated specimens that is null.
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
S
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
n
DURABILITY ASSESSMENT BY SALT
CONCLUSIONS
• On sandstone specimens were applied two ethyl silicates (TG and R).
• Minor harmful characteristics of the R applications on M variety of sandstones and a better consolidation effect of TG.
• Salt crystallization artificial ageing tests highlighted good durability of R applications and a worst behavior of TG treatments.
4
1
th
IA
H
S
W
O
R
L
D
C
O
N
G
R
ESS
O
N
H
O
U
SI
N
G
U
S
T
A
IN
A
B
ILI
T
Y
A
N
D
I
N
N
O
V
A
T
IO
N
FO
R
T
H
E
FU
T
U
R
E
O
S
–
E
x
p
e
ri
m
e
n
ta
l
R
e
s
e
a
rc
h
o
n
B
u
ild
in
g
R
e
h
a
b
ili
ta
ti
o
TH
A
N
K
Y
OU
41th IAHS WORLD CONGRESS ON HOUSING
