A. DUFKA et al.: THE DEVELOPMENT OF NEW TYPES OF SECONDARY PROTECTION ...
533–540
THE DEVELOPMENT OF NEW TYPES OF SECONDARY
PROTECTION FOR CONCRETE STRUCTURES EXPOSED TO
EXTREME CONDITIONS
RAZVOJ NOVIH VRST SEKUNDARNE ZA[^ITE BETONSKIH
KONSTRUKCIJ IZPOSTAVLJENIH EKSTREMNIM POGOJEM
Amos Dufka, Tomá{ Melichar, Jiøí Byd`ovský, Jan Vanìrek
Brno University of Technology, Faculty of Civil Engineering, Institute of Building Materials and Components, Veveøí 95,
602 00 Brno, Czech Republic
dufka.a@fce.vutbr.cz
Prejem rokopisa – received: 2015-08-07; sprejem za objavo – accepted for publication: 2016-06-09
doi:10.17222/mit.2015.249
During their use reinforced concrete structures are exposed to external influences. Nowadays, the reducing effect of these
influences is usually ensured by secondary (barrier) protection. At present, coatings based on organic substances are commonly
used. However, these types of secondary protection show substantial limits under extreme conditions. A method that has consi-
derable potential to eliminate these disadvantages includes the application of secondary protection based on alkali-activated
materials or geopolymers. This paper is focused on the development and optimisation of secondary protection (coating, plaster)
based on alkali-activated materials intended for reinforced concrete structures to be exposed to highly chemically aggressive
environments.
Keywords: coatings, alkali-activated substances, extreme conditions, agressive environment, durability of structures
Med uporabo so armirane betonske konstrukcije izpostavljene zunanjim vplivom. Danes se zmanj{anje vpliva teh u~inkov
zagotovi z uporabo sekundarne za{~ite (prepreka). Obi~ajno se uporabljajo premazi na osnovi organskih snovi. Vendar pa so te
vrste sekundarne za{~ite precej omejene pri ekstremnih pogojih. Metoda s potencialom da odpravi te pomanjkljivosti, vklju~uje
uporabo sekundarne za{~ite na osnovi alkalno-aktiviranih materialov ali geopolimerov. ^lanek obravnava razvoj in optimiranje
sekundarne za{~ite (premaz, omet) na osnovi alkalno aktiviranega materiala, namenjenega za armirane betonske konstrukcije, ki
bodo izpostavljene kemijsko mo~no agresivnemu okolju.
Klju~ne besede: premazi, alkalno-aktivirane snovi, ekstremni pogoji, agresivno okolje, zdr`ljivost konstrukcij
1 INTRODUCTION
The conditions of exploitation are a key factor that
limits the service life of building structures. These
include both physico-mechanical influences (especially
the synergistic effect of moisture and frost, increased
temperature, etc.) and physico-chemical influences
(aggressive substances, biotic agents, etc.). In principle,
the resistance of building structures to negative
influences can be ensured by several approaches, i.e., by
structural design and the resistance of the materials used
(i.e., by primary protection) and, especially, by having
the negative influences of external environment onto the
structure eliminated by a barrier protection. In particular,
this includes coatings, sheets, etc. (i.e., secondary
protection). Presently, a wide range of coating materials
to protect reinforced concrete structures is available. In
general terms, it comprises high-quality materials that,
under standard conditions and withadequate mainten-
ance, contribute considerably to the increased service life
of the structure. This, however, only applies to buildings
exposed to normal conditions.
If, however, the building structures are exposed to
extreme conditions, a different situation will occur. In
some types of chemically aggressive environments, for
example, the coating materials based on organic sub-
stances feature distinct limits. The situation is even more
distinctive in the buildings exposed to increased tem-
peratures. This primarily applies to cases when the
temperature changes are associated with a conspicuous
gradient. Under such conditions, stresses may occur in
the coating-substrate interface due to the different
thermal coefficients of expansion as well as due to
changes in the microstructure of the polymer matrix, and
result in the separation of the coating from the substrate,
cracking, etc.
The development of coating materials with a matrix
based on alkali-activated substances, or geopolymers,
seems to be a very viable material basis making it
possible to solve the above problems. The coating based
on alkali-activated slag presented in this article shall
hereinafter be referred to as AAM coating.
The unique properties of alkali-activated materials
provide assumptions for the development of new secon-
dary protections intended for reinforced concrete con-
structions operated in extreme conditions (for instance,
in environments of synergistic actuation of higher
temperature and chemically aggressive substances, etc.).
Materiali in tehnologije / Materials and technology 51 (2017) 3, 533–540 533
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
UDK 624.012.44:620.1:621.7.016 ISSN 1580-2949
Professional article/Strokovni ~lanek MTAEC9, 51(3)533(2017)
The alkali activated slag material being represented
herein is intended as a secondary protection for rein-
forced concrete constructions. On that basis the pro-
perties of the developed AAM material are compared
with an acrylate co-polymer-based coating intended just
for the constructions exploited in chemically aggressive
environments. In addition, the effect of the selected
aggressive environment type is monitored on cement
concrete without any secondary protection for compa-
rison.
The developed material based on alkali-activated slag
is not developed as repair mortar in this case but as
secondary protection. Within this context the comparison
of the properties of the secondary protection based on
alkali-activated slag with a polymeric coating can
therefore be considered as relevant.
2 SPECIFICATION OF THE COATINGS BEING
DEVELOPED
In general terms, we can say that the coatings based
on alkali-activated materials are made by the poly-
condensation of aluminosilicates at temperatures up to
100 °C. The polymerisation includes the chemical reac-
tions of aluminosilicates (Al3+ in tetrahedral coordina-
tion) and alkaline polysilicates forming polymeric
bindings Si–O–Al. As a result, a solid and compact
structure forming a dominant component of the matrix of
the composite, or coating system, is created.1,2
This paper deals with the development of a coating
system based on alkali-activated substances to be used
for the protection of reinforced concrete structures
exposed to extreme conditions. A typical example
representing such extreme conditions includes the joint
effect of chemically aggressive environments and in-
creased temperature. For example, the structures forming
an integral part of process lines for the production of
chemicals and the like may be subject to such exposure.
Due to the specifics of the above productions, the
reinforced concrete structures are frequently loaded by a
cyclic effect of increased temperatures for long periods
and exposed, on practically a continuous basis, to the
effects of aggressive chemicals. The above-mentioned
facts have been taken into account during the develop-
ment of the coating system.
3 EXPERIMENTAL PART
The previous researches made in this field have been
followed by the development of an alkali-activated
coating. In terms of the service life and functionality of
the coating system being developed, its adhesion to the
substrate represents one of key parameters. With regard
to this fact, the alkali-activated matrix was modified by a
polymer dispersion. The coating composition obtained
by the optimisation process is shown in Table 1. The
optimisation process for AAM-based coating develop-
ment follows the research presented in 1–4. For instance,
the effect of the water glass silicate module is examined
in this case in relation to the slag chemical composition,
further to the glass-phase content in it, etc. Optimizing
the granulometry and the amount of filler used, for
example, was based on data provided in 5,6.
Table 1: Composition of AAM coating
Tabela 1: Sestava AAM premaza
Coating component Content of component (w/%)
Water glass 16
Polymer dispersion 2
Slag 31
Filler – silica sand, fraction
of 0.45 mm 44
Water 7
For the water glass used, a silicate modulus of 1.7
was applied. Primarily, the water glass silicate module
drew from the findings presented in 1,4,5. The chemical
composition of the water glass is shown in Table 2.
Table 2: Chemical composition of water glass
Tabela 2: Kemijska sestava vodnega stekla
Component of water glass Content of component (w/%)
SiO2 21.41 %
Na2O 12.81 %
K2O 0.62 %
CaO 0.02 %
The polymer dispersion used was based on vinyl
acetate ethylene copolymer. For the chemical compo-
sition of the slag, please refer to Table 3.
Table 3: Chemical composition of slag
Tabela 3: Kemijska sestava `lindre
Component of slag Content of component (w/%)
CaO 35.9
SiO2 40.1
Fe2O3 6.9
Al2O3 8.2
Na2O 2.1
K2O 0.9
P2O5 1.4
MgO 2.1
MnO 0.3
The experiments were aimed at the development of a
coating to be resistant as much as possible to extreme
conditions, i.e., to the synergistic effect of highly
chemically aggressive environments and increased
temperature. In particular, the coating was exposed to the
saturated solution of ammonium sulphate with a part of
ammonia sulphate not already dissolved in the suspen-
sion. The solution temperature was 50 °C. The test
samples were prepared so that the developed coating was
applied to the concrete substrate using a roller (concrete
class C30/37 was used). In order to assess the resistance
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of the AAM coating in an impartial manner, a com-
mercially available coating based on acrylate copolymer
was exposed to the same type of aggressive environment.
We used a coating designed by its manufacturer to
protect the surface of the reinforced concrete structures
exploited in chemically aggressive environments. Here
again, test samples were prepared so that the coating was
applied on the substrate consisting of concrete, class
C30/37. The coating was applied in accordance with the
applicable product’s technical data sheet (i.e., especially
in regard to the coating consumption and the method of
application). Furthermore, the effect of the test environ-
ment was tested directly on the uncoated concrete; again,
concrete class C30/37 was used. For both coating types
(i.e., the developed AAM coating and the commercially
available coating based on acrylate copolymer) as well as
for the uncoated concrete, two sets of test specimens
were prepared. The samples of the first set were kept
under laboratory conditions for the entire period of the
experiment (i.e., t = 20±2 °C, % = 50±5 %). The values
found in these specimens were considered as a reference.
The test samples of the second set were exposed to the
saturated solution of ammonium sulphate at increased
temperature for periods of 3 months and 6 months. The
test solution was prepared with an excessive amount of
ammonium sulphate that remained unsolved. The solu-
tion temperature was maintained at 50 °C. Test samples
aged for 28 d were placed in this aggressive environ-
ment.
In order to assess the effect of the test environment,
individual test samples were then subject to the follow-
ing determinations after the 3-month and 6-month
exposures:
• Visual evaluation – the condition of coatings was
primarily assessed in terms of the potential occur-
rence of cracks (^SN EN ISO 4628-4) and blistering
(^SN EN ISO 4628-2). For the uncoated concrete,
the appearance of the concrete surface layers was
assessed;
• Determination of the coating thickness (^SN EN ISO
2808);
• Determination of the coating adhesion to the sub-
strate (^SN EN ISO 4624). For the uncoated con-
crete, the tensile strength of the concrete surface
layers was observed (^SN 73 1318). During this test
a disk with a 50-mm diameter is glued on the surface
of the concrete being evaluated and it is cut to clearly
define the loaded area. During this test the defined
area is loaded by tensile force up to the breakage
limit of the tested material;
• Determination of the water-tightness of coatings
(^SN 73 2578). This test proves the coating system’s
ability to hold water in the liquid state. The test result
is expressed as the amount of water that passed
through the coating in the screeding materials
(without any actuation of the hydrostatic pressure)
within 30 min; the unit is therefore 1 litre of water
related to 1 m2 of the tested surface;
• Analyses of the microstructure using a scanning
electron microscope (methodological procedure No.
30-33/1 by Brno University of Technology, Faculty
of Civil Engineering).
The mentioned complex of the experiments followed
de facto the stipulations of the standards involved in
questions of the rehabilitation of reinforced concrete
constructions ^SN EN 1504-1 and ^SN EN 1504-2.
4 RESULTS
4.1 Visual evaluation
Attention was primarily paid to the evaluation of the
condition of the surface layers of the tested samples. In
the sample with the developed AAM coating, it was
found that even the 6-month exposure to the test envi-
ronment did not cause any changes to the coating that
would prove its degradation due to aggressive sub-
stances. Even after the completion of the experiment, the
coating structure remained practically identical. This
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MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 2: Macroscopic view of the structure of developed AMM
coating after a 6-month exposure to ammonium sulphate
Slika 2: Makroskopski izgled konstrukcije z AMM premazom po
{estih mesecih izpostavitve amonijevemu sulfatu
Figure 1: Macroscopic view of the structure of developed AMM
coating prior to its exposure to aggressive environments
Slika 1: Makroskopski izgled konstrukcije z AMM-premazom pred
izpostavitvijo agresivnemu okolju
situation is documented in the following photographs
(Figures 1 and 2):
It was concluded that even a 6-month exposure of the
AAM coating would not cause any significant change in
the structure of the surface layers of the AAM coating. In
addition, the visual evaluation did not reveal any evident
presence of cracks or any other defects. Yet, a different
situation was found in the coating based on acrylate
copolymer. In this case, a 6-month exposure to the solu-
tion of ammonium sulphate and an increased tempera-
ture resulted in the coating’s degradation. This fact is
documented in the following photographs (Figures 3 and 4).
The evident destruction of the surface layers of the
coating is shown in Figure 3. The destroyed surface
layers of the coating film (i.e., flaking of the coating)
and cracks are shown in Figure 4.
Furthermore, it was proven that the effect of the test
environment on the concrete without secondary pro-
tection caused a significant degradation of the cement
matrix. The visual evaluation revealed a change in the
colour of surface layers, and especially the occurrence of
cracks and local separations of surfaces layers (i.e., of
concrete up to a depth of approx. 5 mm) from the
substrate (Figure 5).
4.2 Determination of coating thickness
Coating thickness is one of the key factors deter-
mining the protective function of the coating. Besides, it
is a parameter, the monitoring of which, or monitoring of
changes in coating thickness, makes it possible to
carefully assess the development of the coating degra-
dation due to the aggressive environment. The coating
thickness was measured prior to placing the individual
samples in the aggressive environment (the samples were
28 d old) and then after 3-month and 6-month exposures
to aggressive environments. The coating thickness was
measured using a cutting method and procedure
according to the ^SN EN ISO 2808 standard. For the
results of the coating thickness measurements, please
refer to Table 4. The shown values represent an
arithmetic mean of ten measurements.
Table 4: Coating thickness
Tabela 4: Debelina premaza
Type of coating Placement
Exposure time
28 d 3 months 6 months
Developed
AAM coating
Laboratory
environment 520 μm 510 μm 515 μm
Aggressive
environment — 500 μm 490 μm
Commercially
available coat-
ing based on
acrylate copo-
lymer
Laboratory
environment 410 μm 415 μm 410 μm
Aggressive
environment — 350 μm 290 μm
Evaluation
It was proven that even a 6-month exposure would
not cause any significant change of the thickness of the
AMM coating. Yet, a different situation occurred in the
commercially available coating. In this coating, the
A. DUFKA et al.: THE DEVELOPMENT OF NEW TYPES OF SECONDARY PROTECTION ...
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Figure 4: A 6-month exposure to the test environment caused the
degradation of the coating based on copolymer acrylate
Slika 4: [estmese~na izpostavljenost preizkusnemu okolju je povzro-
~ila degradacijo premaza na osnovi kopolimernega akrilata
Figure 5: A 6-month exposure to the test environment caused a
massive degradation of surface layers of uncoated concrete
Slika 5: [estmese~na izpostavljenost preizkusnemu okolju je povzro-
~ila mo~no degradacijo povr{ine betona brez premaza
Figure 3: View of the macrostructure of coating based on acrylate
copolymer after a 6-month exposure to the test environment
Slika 3: Izgled makrostrukture premaza na osnovi akrilatnega poli-
mera po {estih mesecih izpostavljenosti preizkusnemu okolju
effect of the aggressive environment resulted in a
thickness reduction by approximately 30 %. This finding
is in full compliance with the visual evaluation that
revealed a degradation of the coating based on acrylate
copolymer (i.e., especially fissures, separations of
surface layers of the coating, etc.). This degradation of
the surface layers of the coating film, in particular, has
then become the dominant cause of thickness reduction
for the commercially available coasting.
4.3 Determination of coating adhesion to a substrate
Adhesion to a substrate is another parameter that is
quite critical in terms of the protective function and
service life of the coating. Coating-substrate adhesion
was determined in accordance with the applicable
provisions of the ^SN EN ISO 4624 standard. In
addition, the effect of concentrated ammonium sulphate
and increased temperature was tested in the uncoated
concrete. The concrete was subjected to pull-off testing,
and the tensile strength of the surface layers was deter-
mined using the procedure according to the ^SN 73
1318 standard.
For the results of the determination of coasting-
substrate adhesion, or a determination of the tensile
strength of the concrete surface layers, please refer to
Table 5. The values shown represent an arithmetic mean
of five measurements.
Table 5: Determination of coating-substrate adhesion
Tabela 5: Dolo~anje adhezije premaz-podlaga
Type of
material Placement
Exposure time
28 d 3 months 6 months
Developed
AAM coating
Laboratory
environment 2.1 MPa 2.4 MPa 2.6 MPa
Aggressive
environment — 2.2 MPa 2.0 MPa
Commercially
available
coating based
on acrylate
copolymer
Laboratory
environment 2.9 MPa 3.0 MPa 2.9 MPa
Aggressive
environment — 1.6 MPa 0.9 MPa
Uncoated
concrete
Laboratory
environment 2.6 MPa 2.9 MPa 3.0 MPa
Aggressive
environment — 0.9 MPa 0.2 MPa
Evaluation
It was concluded that the test environment caused a
degradation of the uncoated concrete, which resulted, for
example, in a distinct decrease in the tensile strength of
the surface layers. A significant decrease in the coating-
substrate adhesion after the exposure to the test environ-
ment was found for the coating based on acrylate
copolymer. The coating material itself, not the coating-
substrate interface, was the area in which the defects
were mainly revealed after pull-off testing. The smallest
decrease in adhesion to the substrate was detected in the
AMM coating. In this type of coating, a 6-month
exposure to the test environment caused only a decrease
of approximately 25 %. The AAM coating-substrate
interface was the area with the most frequent occurrence
of defects.
4.4 Determination of coating water-tightness
The water-tightness of the coatings was determined
using the procedure according to the ^SN 73 2578
standard. For the test results, please refer to Table 6; the
values represent an arithmetic mean of five measure-
ments.
Table 6: Coating water-tightness
Tabela 6: Vodotesnost premaza
Type of coating Placement
Exposure time
28 d 3 months 6 months
Developed AAM
coating
Laboratory
environment 0.9 l.m
–2 0.9 l.m–2 0.8 l.m–2
Aggressive
environment — 1.0 l.m
–2 1.1 l.m–2
Commercially
available coating
based on acrylate
copolymer
Laboratory
environment 0.2 l.m
–2 0.2 l.m–2 0.2 l.m–2
Aggressive
environment — 0.6 l.m
–2 0.9 l.m–2
Evaluation
The testing shows that the water-tightness of the
developed AAM coating is lower when compared to the
acrylate coating. In terms of water-tightness, the AAM
coating satisfied the requirements for vapour-permeable
coatings, while the coating based on acrylate copolymer
has, in terms of this parameter, satisfied the requirements
for vapour-tight coatings. However, it was proven that
the water-tightness of the coating based on acrylate
copolymer rapidly decreased when exposed to the test
environment. A 6-month exposure to the test environ-
ment caused a more than four times lower water-tight-
ness of the coating based on the acrylate copolymer. In
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MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 6: View of the microstructure of AAM-based coating. The
coating structure is compact. 100× magnification
Slika 6: Izgled makrostrukture premaza na osnovi AAM. Struktura
premaza je kompaktna. Pove~ava 100×
this case, the decrease in water-tightness is associated
with the impaired compactness of the coating due to
defects (occurrence of microcracks, etc.). In the AAM
coating, the changes due to the test environment were not
so distinct.
4.5 Analysis of microstructure with the electron micro-
scope
Using the electron microscope, the microstructure of
individual materials and, in particular, the changes
caused by the effects of an aggressive environment were
analysed. Hence, this method was primarily considered
as comparative; it means that the samples were primarily
compared prior to and after the exposure to laboratory
conditions.
Evaluation
The analysis of the microstructure with the electron
microscope confirmed and further extended our knowl-
edge obtained during the previous determinations. The
resistance of the AAM coating to the effects of the test
environment was confirmed. The fact that the structure
of AAM coating is relatively compact is shown in
Figure 6. To increase the adhesion to the substrate,
AAM coating was modified with a polymer dispersion.
This fact resulted in a partial increase in the porosity of
the coating structure (Figure 7). Pseudomorphs of cal-
cium hydrosilicate gels represent a dominant component
of AAM-based coating (Figure 8). Calcium hydrosili-
cate phases are still dominant components of
AAM-based coating also after a 6-month exposure to the
test environment (Figure 9). Special attention was
focused on the analysis of the interface AAM paint/con-
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Figure 10: View of the AAM coating/concrete substrate interface
after a 6-month exposure to the test environment. 600× magnification
Slika 10: Izgled stika AAM premaza/betonska podlaga po izpostavitvi
{est mesecev preizkusnemu okolju. Pove~ava 600×
Figure 8: Pseudomorphs of calcium hydrosilicate gels in AAM-based
coating – a sample placed at laboratory conditions. 5000× magni-
fication
Slika 8: Psevdomorfija kalcijevega hidrosilikatnega gela v premazu na
osnovi AAM – vzorec izpostavljen laboratorijskim pogojem. Pove~ava
5000×
Figure 9: View of the microstructure of AAM-based coating after a
6-month exposure to the test environment. 5000× magnification
Slika 9: Izgled mikrostrukture premaza na osnovi AAM, po {est
mese~ni izpostavitvi preizkusnemu okolju. Pove~ava 5000×
Figure 7: To increase the adhesion to the substrate, AAM coating was
modified with polymer dispersion. 100× magnification
Slika 7: Za pove~anje adhezije na podlago, je bil AAM premaz
modificiran z disperzijo polimera. Pove~ava 100×
crete. It was found that the interface structure is compact.
The absence of any corrosive new formations both in the
coating and in the substrate is evident (Figures 10 and
11).
Conversely, the surface layers of the concrete pro-
tected with the coating based on acrylate copolymer have
proven that the exposure to an aggressive environment
cause negative changes in the microstructure of the
surface layers of the concrete substrate. It was found that
the microstructure of this concrete has been subject to
negative changes – new formations of ettringite and
gypsum have been created (Figures 12 and 13).
The degradation due to the test environment has
shown itself to an extreme degree in the concrete that
was not protected with any coating during the exposure.
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Figure 14: View of the structure of uncoated concrete after a three-
month exposure to the test environment. The creation of corrosive
products (gypsum pseudomorphs) in the microstructure is evident.
4200× magnification
Slika 14: Izgled zgradbe iz neza{~itenega betona po treh mesecih
izpostavitve preizkusnemu okolju. Viden je nastanek korozijskih pro-
duktov (psevdomorfija mavca). Pove~ava 4200×
Figure 11: Detailed view of the AAM coating/concrete substrate
interface after a 6-month exposure to the test environment. 1000×
magnification
Slika 11: Detajl izgleda stika AAM premaz/betonska podlaga, po
izpostavitvi {est mesecev preizkusnemu okolju. Pove~ava 1000×
Figure 15: Detailed view of corrosive new formations (gypsum) in the
microstructure of cement matrix after a 6-month exposure to the test
environment. 4500× magnification
Slika 15: Detajl korozijskih produktov (mavec) v betonski osnovi po
izpostavitvi {est mesecev preizkusnemu okolju. Pove~ava 4500×
Figures 12 and 13: View of the structure of surface layers of the
concrete that was protected with acrylate copolymer-based coating
and exposed to an aggressive environment for a period of 6 months.
4200× magnification
Sliki 12 in 13: Izgled zgradbe povr{inske plasti betona, ki je bil
za{~iten s prematom na osnovi akrilatnega polimera in izpostavljenega
agresivnemu okolju za dobo {est mesecev. Pove~ava 4200×
12)
13)
In that case, the development of corrosive new forma-
tions (mainly of gypsum) was essential (Figures 14 and
15).
5 CONCLUSIONS
The performed experiments have confirmed that the
synergistic effect of the concentrated solution of
ammonium sulphate and the increased temperature
results in a significant degradation of the coating based
on acrylate copolymer. In this type of coating, the utility
parameters have decreased despite the fact that the
coating is designed for chemically aggressive environ-
ments. It is just the synergistic effect of chemicals and,
in particular, of increased temperatures that can be
designated as the primary cause of such a negative effect
of the test environment.
In turn, positive results have been achieved with the
coating based on alkali-activated slag using appropriate
types of modifying additives. It has been confirmed that
this type of coating is able to effectively withstand the
joint effect of chemically aggressive substances and
increased temperature. For any of the parameters
observed, no decrease greater than 25 % has been found.
The listed findings unambiguously confirm the potential
for the use of material based on alkali-activated sub-
stances for the secondary protection of reinforced
concrete structures exposed to extreme conditions. The
development of this type of coating has not been com-
pleted yet, but it is still ongoing. In the following stages,
attention will be paid, for example, to the possibility of
having the autogenous shrinkage limited using nano-
sized reinforcements, to the application of modifying
additives; hence, the analysis of the AAM coating/con-
crete substrate interface, etc. will become an important
research area.
Acknowledgements
This research was conducted with the financial help
of project GA^R 14-25504S Research of Behaviour of
Inorganic Matrix Composites Exposed to Extreme Con-
ditions and the project No. LO1408 AdMaS UP
– Advanced Materials, Structures and Technologies,
supported by Ministry of Education, Youth and Sports
under the National Sustainability Programme I.
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MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS