Uploaded by IAEME PUBLICATION

CHARACTERISTICS OF THE REINFORCED CONCRETE CONSTRUCTIONS AND STRUCTURES OPERATED IN THE COASTAL ZONE OF THE BLACK SEA COAST

advertisement
International Journal of Civil Engineering and Technology (IJCIET)
Volume 10, Issue 04, April 2019, pp. 626–634, Article ID: IJCIET_10_04_065
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJCIET&VType=10&IType=4
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
Scopus Indexed
CHARACTERISTICS OF THE REINFORCED
CONCRETE CONSTRUCTIONS AND
STRUCTURES OPERATED IN THE COASTAL
ZONE OF THE BLACK SEA COAST
Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna,
Kuznetsov Vladimir Aleksandrovich, Smolinskiy Nikolay Yakovlevich,
Kharchenko Maria Sergeyevna, Kovalenko Tatyana Anatolyevna,
Bormotina Anastasia Mikhailovna, Khalitova Anzira Rustamovna
Moscow State University of Civil Engineering (MGSU) National Research University,
26, Yaroslavskoye Shosse, Moscow, Russia
ABSTRACT
Concrete and reinforced concrete are used for the construction of buildings and
structures with long-term operation. The use of structures made of these building
materials is massive, and more than 4.5 billion m3 per year of concrete and reinforced
concrete are produced in the world to meet the requirements in the building industry.
During operation, structures are often exposed to adverse environmental effects
(aggressive chemicals in the form of gases, salt solutions and aerosols,
microorganisms) and turn out to be in difficult working conditions.
These effects contribute to the destruction of materials and reduce the durability of
structures, which in some cases may fail within a year or even months after the start of
operation. When building objects are located near industrial enterprises and on the
coast, the impact of adverse factors may increase.
The article presents the results of a study of the content of inorganic salts and the
species composition of microorganisms in the surface layer of concrete in reinforced
concrete structures operated on the Black Sea coast. The authors presented the results
of the study of samples of concrete taken from the structures of the pier, which was in
direct contact with sea water, depending on elevations relative to sea level and
orientation to the cardinal points.
The results of the study of samples taken from the structures of the fence, located
at a distance of about 50 m from the coastal edge, depending on the orientation of the
fence on the cardinal points and its parallel or perpendicular position relative to the
coastline were also obtained.
A correlation was found between the levels of salt content and the types of
microorganisms inhabiting the surface layer of concrete in coastal structures. It has
been established that under the influence of the sea climate, a simultaneous impact on
building structures of high air temperature, solar radiation, wind, biological
environment, moisture and impurities of hygroscopic sea salts in the air occurs.
http://www.iaeme.com/IJCIET/index.asp
626
[email protected]
Characteristics of the Reinforced Concrete Constructions and Structures Operated in the Coastal Zone of the
Black Sea Coast
The intensity of the impact of negative factors depends on the elevations of the
location of the structures relative to the surface of the water and their orientation
relative to the coast and to the cardinal points.
Key words: aggressive environmental impact; salt sprays; concrete and reinforced
concrete; biodegradation; concrete destruction; structures and facilities; corrosion;
microorganisms; salt content.
Cite this Article: Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna, Kuznetsov
Vladimir Aleksandrovich, Smolinskiy Nikolay Yakovlevich, Kharchenko Maria
Sergeyevna, Kovalenko Tatyana Anatolyevna, Bormotina Anastasia Mikhailovna,
Khalitova Anzira Rustamovna, Characteristics of the Reinforced Concrete
Constructions and Structures Operated in the Coastal Zone of the Black Sea Coast,
International Journal of Civil Engineering and Technology 10(4), 2019, pp. 626–634.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=4
1. INTRODUCTION
Concrete and reinforced concrete are one of the main types of building materials, which are
widely used for the erection of buildings and structures with planned long-term operation - up
to 100 years or more. To meet the needs of construction, more than 4.5 billion m3 per year of
concrete and reinforced concrete are produced worldwide.
Due to the difficult working conditions in some cases, the construction of these materials
may be short-lived and fail after a year or months of operation. Substances added to the
material during its production, as well as the environment with admixtures of aggressive
components, influence the durability of concrete.
For example, ambiguous effects on concrete and reinforced concrete structures have
chemical additives introduced into the building material to improve the technological
properties of the concrete mix. In study [1] it is noted that ―for the majority of groups of
additives in general and specific types of additives, in particular, side effects are
characteristic. They can be no less strong and no less significant than the main effect as they
can be both positive and negative. "
Basically the negative effect of the use of additives is detected during overdose [2], then
the appearance of efflorescence, the occurrence of corrosion and wet spots on the surface of
structures, the cracking of reinforcement, etc., is possible.
According to research by a number of authors [3, 4, 5], it has been established that up to
75% of concrete and reinforced concrete building structures are exposed to the damaging
effects of the environment with constantly deteriorating indicators.
The speed and scale of damage to such structures are associated with corrosion caused by
the aggressive influence of the external environment, which ―is capable of weakening
concrete strength over time, thereby reducing the safety and durability of buildings and
structures‖ [6].
It has been established that the less aggressive environmental impact is taken into account
in the design calculations during design, the more pronounced the corrosion becomes during
the operation of buildings and structures [7] throughout the entire life cycle.
Corrosive damage of the reinforced concrete structures is caused by exposure of the
surrounding air environment, groundwater with aggressive substances [8]. Also,
environmental factors that adversely affect the initial properties of concrete include: the action
of elevated and lowered temperatures, ultraviolet radiation, temperature conditions that cause
alternate freezing and thawing of building materials. Such impacts are specific to the
http://www.iaeme.com/IJCIET/index.asp
627
[email protected]
Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna, Kuznetsov Vladimir Aleksandrovich,
Smolinskiy Nikolay Yakovlevich, Kharchenko Maria Sergeyevna, Kovalenko Tatyana Anatolyevna,
Bormotina Anastasia Mikhailovna, Khalitova Anzira Rustamovna
operating conditions of the structures of buildings and structures located on the coasts of the
seas.
To these adverse effects, the effect on the structure of seawater and salt fog with chloridecontaining environment [9, 10, 11, 12] in the form of an aerosol of hygroscopic salts is added.
Along with inorganic substances, microorganisms affect the corrosion damage of
concrete. According to a number of researchers, ―more than 40% of the total biodegradation is
associated with the activity of microorganisms — bacteria and fungi‖ [13, 14, 15].
The processes of bio deterioration of reinforced concrete structures in the warm and
humid climatic conditions of the construction area are intensified [16], which is caused by the
presence of factors that ―stimulate reproduction: high humidity, relatively high temperatures,
various kinds of pollution, as well as potential differences and a pH shift of the environment‖
[17]. The development, reproduction and change of species of bacteria is caused by a change
in the characteristics of the environment over time [18]. Biodeteriorations are also typical for
polymer composite materials, in particular, polymer concrete [16, 19, 20, 21].
2. STATEMENT OF THE PROBLEM AND RESEARCH METHODS
The task was to establish the species composition of microorganisms and the content of
inorganic salts in the surface layer of concrete structures used on the Black Sea coast. The
species composition of microorganisms was established in the National Research Mordovia
State University. N.P. Ogareva ‖ Saransk city, using the standard method in accordance with
the identification of micromycetes on the basis of their morphological and cultural
characteristics using determinants: K.B. Raper, S.A. Tom (Raper, Nhom, 1949); K.B. Raper,
D.I. Fennel (Raper, Fennell, 1965); N.M. Pidoplichko (1971); M.A. Litvinov (1967); A.A.
Milko (1974); TS Kirilenko (1977); C. Donsch, V. Gams (Donch, Gams, 1980); A.Yu.
Lugauskas, A.N. Mikulskene, D.Yu. Shliauzeni (1987); V.I. Bilay, E.Z. Koval (1988) [16].
The chemical analysis of material samples on the quantitative content of inorganic salts
was carried out according to the standard methods adopted in analytical chemistry in the
analytical laboratory of Pigment PJSC, Tambov city. The determination of chlorides was
made by the universal ion-meter EV-74, and the determination of sulfates was made by a
photoelectric photometer KFK-3- "ZOMZ".
3. THE RESULTS OF RESEARCH
During this period its structural elements have not been repaired. Samples were taken at two
characteristic vertical portions of the pier, oriented along the cardinal points, respectively, to
the east and to the west (Pic. 1). One altitude mark for material sampling was assigned at a
level below 1 m from the level of a smooth surface of water, the other one was assigned at
the level of a surface of water; the third one was assigned at a height of 2 m above the water
level.
The first stage of the study consisted in determining the salt content and the presence of
microorganisms in the surface layer of concrete in a reinforced concrete pier and comparing
the values obtained for different elevation marks of sampling points.
http://www.iaeme.com/IJCIET/index.asp
628
[email protected]
Characteristics of the Reinforced Concrete Constructions and Structures Operated in the Coastal Zone of the
Black Sea Coast
N
Figure 1 Sampling site (highlighted by authors with red color) of pier concrete structures on the map
The source of the presence of salts in the surface layer of concrete piers, as structures that
are in direct contact with the sea, is sea water and salt fog. It is known that the salt content in
seawater averages 3.5% (mass.), chlorides, sodium and sulfates constitute the largest part of
it: Cl - 55%, Na - 30.6%, SO4 - 7.7%. The remaining substances are magnesium, calcium and
potassium: Mg - 3.7%, Ca - 1.2%, K - 1.1% 2.
Table 1 Results of microbiological and chemical analysis of samples of concrete of the coastal pier in
Gelendzhik
Therefore, in the samples of concrete, the presence of salts, such as chlorides and sulfates,
are represented massively [22].
http://www.iaeme.com/IJCIET/index.asp
629
[email protected]
Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna, Kuznetsov Vladimir Aleksandrovich,
Smolinskiy Nikolay Yakovlevich, Kharchenko Maria Sergeyevna, Kovalenko Tatyana Anatolyevna,
Bormotina Anastasia Mikhailovna, Khalitova Anzira Rustamovna
Data on the microbiological and chemical analysis of samples of the surface layer of
concrete of the coastal pier in the city of Gelendzhik on the Black Sea coast are presented in
Table 1.
In accordance with the data presented in Table 1, the smallest composition of
microorganisms is observed in concrete below the surface of seawater. So at a depth of 1 m,
three types of microorganisms such as: Aspergillus niger, Fusarium moniliforme,
Cladosporium elatum were identified.
At the level of the water surface in the pier material, six species of microorganisms were
identified, to the above mentioned: Alternaria brassicae, Cladosporium herbarum and
Aspergillus oryzae were added. In samples taken at a height of 2 m above sea level, five types
of microorganisms were identified. At the same time, Cladosporium elatum, Aspergillus
oryzae and Cladosporium herbarum are absent from those identified at the water level.
Additionally, the following species: Chaetomium dolichortrichum and Penicillium
chrysogenum have been identified.
The average and total salt content was, respectively, in concrete below the surface of
seawater at a depth of 1 m - 0.78 and 1.56 w. %, at the level of the water surface - 1.40 and
2.80 w. %, and at an altitude of 2 m above sea level - 1.35 and 2.69 w. %. It was revealed that
the salt content values are correlated with the species composition of microorganisms in the
samples of the pier material.
Analysis of salt content in samples of the material depending on the orientation of
sampling points along the cardinal points showed that the total salt content was higher at all
elevations relative to sea level. When the vertical pier wall was oriented to the west compared
to the east-oriented wall and there were: at points on 1 m below sea level - 1.09 against 0.47
w. %, at the level of the surface of the water - 2.04 against 0.76 w. %, at the level of 2 m
above sea level - 1.61 against 1.07 w. % The greatest difference in salinity levels for sampling
point No. 2 of western orientation compared to point No.1 of eastern orientation was observed
for samples taken at the water surface level - by 63 rel. % For samples below sea surface 1 m,
the difference was 57rel. %, and for samples at a height of 2 m above the water level was 34
rel. %
Thus, for these conditions, the highest salt content was revealed with the western
orientation of the pier wall as compared with the eastern one.
At the second stage, studies of a reinforced concrete fence (Pic. 2), made of fence panels
of 3.00 × 0.08 × 2.00 (h) m, were carried out. The indicators of reinforced concrete products
at a distance of about 50 m to the seawater edge were compared, because it is known that the
greatest number of microorganisms is detected on samples taken from reinforced concrete
structures 50 meters and more from the sea [16].
The lifetime of the fence is more than 30 years, repair work on its restoration has not been
carried out. Material samples were taken from structures that were arranged parallel and
perpendicular to the seawater edge at the same time from 2 sides of the structures - facing the
sea and on the reverse side.
The orientation of the fence to the cardinal points was also established: at the location of
the structure parallel to the edge of the sea, it had the orientation of the front side - to the
northeast (C-B), and the back side - to the south-west (SW). For the fence, located
perpendicular to the coastal edge, the front side was oriented to the south-east (SE), and the
rear side - to the north-west (North-west).
http://www.iaeme.com/IJCIET/index.asp
630
[email protected]
Characteristics of the Reinforced Concrete Constructions and Structures Operated in the Coastal Zone of the
Black Sea Coast
N
Figure 2 Sampling site (highlighted by the authors with red color) of the reinforced concrete fence
structures on the map
A visual inspection of the reinforced concrete structures of the fence revealed that the face
layer of structures located parallel to the sea and facing the sea, i.e., N-E orientation,
underwent the greatest damage (Pic. 3). The armature of intake elements has traces of
corrosion.
Figure 3 The samples of the reinforced concrete structures of the fence at their location: a, b - parallel
to the sea coast with orientation: a - to the sea (N-E), b - from the sea (S-W); c, d - perpendicular to the
sea coast with orientation: c - to the sea (SE), d - from the sea (NW)
The species composition of microorganisms on the surface of structures is established. It
is more widely expressed on surfaces facing seaward, at N-E and S-E orientation 9 types of
http://www.iaeme.com/IJCIET/index.asp
631
[email protected]
Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna, Kuznetsov Vladimir Aleksandrovich,
Smolinskiy Nikolay Yakovlevich, Kharchenko Maria Sergeyevna, Kovalenko Tatyana Anatolyevna,
Bormotina Anastasia Mikhailovna, Khalitova Anzira Rustamovna
microorganisms were found, compared with surfaces facing "from the sea", at C-W and SW
orientation 6 types of microorganisms are found.
Out of six species of microorganisms listed in Table 2, identified on the side facing "from
the sea", in the samples of fence designs facing the sea, 2 species such as Penicillium
chrysogenum and Penicillium nigricans were missing. 5 species such as - Aspergillus
clavatus, Fusarium moniliforme , Fusarium avenaceum, Aspergillus niger and Aspergillus
oryzae were additionally found , i.e., nine species of microorganisms were present.
The level of salt content in structures located parallel to the coast and facing ―seawards‖
(orientation to N-E) was 16 rel. % higher than in structures located to the side "from the sea"
with a focus on S-W (Table 2).
Table 2 Species composition of microorganisms in the samples of structural elements of the
reinforced concrete fence in the coastal zone of the Black Sea coast
At the third stage of the study, an analysis was made of the wind rose in Gelendzhik (Pic.
4), which showed that the NE direction of the wind (17.8% repeatability) compared with the
SW direction (8.2% repeatability) prevails 2.2 times.
Therefore, it is obvious that the accumulation of salts in the structures of the fence parallel
to the coast and seawards, having a NE orientation, is due to the introduction of salt aerosol
structures from the sea to the surface of the building material. At the same time, the back side
of the fence structure, oriented to SW, undergoes wind impact of lesser intensity and is more
protected by that part of the fence, which has a direction perpendicular to the seashore.
Analysis of the data in Table 2 allowed to establish that on the obverse (orientation to the
SE) and the rear sides (orientation to the NW) of the fence located perpendicular to the sea
shore, the salinity is at the same level as the salinity in the structures parallel to the seashore.
And it converts "from the sea" with a focus on SW, as well as 16 rel. % lower than in
constructions located in the direction ―seawards‖ with orientation to NE.
When the fence is oriented perpendicular to the seashore, its front side facing the sea and
to the SE is exposed to less aerosol of sea salt due to its perpendicular orientation, as well as
http://www.iaeme.com/IJCIET/index.asp
632
[email protected]
Characteristics of the Reinforced Concrete Constructions and Structures Operated in the Coastal Zone of the
Black Sea Coast
the smaller impact of the SE wind, the frequency of which is 13% against the NE wind
repeatability 17.8% for the fence parallel orientation relative to the coast in the direction NE.
Figure 4. Wind rose in Gelendzhik
Solar radiation also affects the destruction of the surface layer of a concrete fence. At the
same time, its impact is complex, since with the existing location of the fence, its mutually
perpendicular sides, turned "from the sea" during the daylight hours cast a shadow on each
other.
The analysis of the amount of total solar radiation (direct and diffuse) on the vertical
surface of the fence structures with a cloudless sky is carried out without taking into account
that the surface under study is in the shadow of a perpendicular structure.
Total solar radiation was determined in accordance with the data of the Code of Practice
for the location: Gelendzhik, height above sea level is 22 m, geographical coordinates are 44 °
33′43 ″ north latitude and 38 ° 05′05 ″ east longitude. The results of the sample are shown in
Table 3.
With the NE and NW orientation of the fence, the magnitude of the total solar radiation is
575 kWh / m2. With SE and SE orientations are 1594 kWh / m2. It is known that when
exposed to solar radiation, significant stresses occur in the body of structures due to the
radiation amplitude and inhomogeneous composition of the material. Therefore, when
exposed to solar radiation, it is possible to destroy the material by the action of the salt and
microbiological environment more intensively.
Table 3. The value of the total solar radiation (direct and diffuse) on a vertical surface with a cloudless
sky, kWh / m2
http://www.iaeme.com/IJCIET/index.asp
633
[email protected]
Kazakov Sergey Dmitrievich, Bryl Julya Sergeevna, Kuznetsov Vladimir Aleksandrovich,
Smolinskiy Nikolay Yakovlevich, Kharchenko Maria Sergeyevna, Kovalenko Tatyana Anatolyevna,
Bormotina Anastasia Mikhailovna, Khalitova Anzira Rustamovna
4. CONCLUSIONS
The study showed that under the influence of the Black Sea climate, simultaneous exposure of
building structures to variable positive temperatures, solar radiation, wind, biological
environment, moisture and impurities of hygroscopic sea salts in the air occurs.
The intensity of the impact of negative factors depends on the elevations of the location of
the structures relative to the surface of the water, as well as their orientation relative to the
coastal edge and to the cardinal points. At the same time, orientation to the cardinal points is
the determining factor for taking into account the influence of wind and solar radiation.
REFERENCES
[1]
Kuderskaya, O.O. Study of the effect of HSTN additive on the development of corrosion
and the formation of efflorescence on the concrete surface // Vestnik of Kuzbass, State
Technical University. - Publishing house of the Kuzbass State Technical University.
named after T.F. Gorbachev (Kemerovo). - 2017. - №4. - p. 141-143.
[2]
Bazhenov, Yu.M. Concrete technology. - M .: Publishing House ASV, 2015. - 500 p.
[3]
Alekseev, S.N, Ivanov, F.M., Modry, S., Schissl, P., Durability of Reinforced Concrete in
Aggressive Environments. - M., 2016. - 316 p.
[4]
Alekseev S.N., Rosenthal N.K. Corrosion resistance of reinforced concrete structures in an
aggressive industrial environment. - M.: Stroiizdat, 2016. - 205 p.
[5]
Mathematical models of concrete corrosion processes / B.V. Gusev, A.S. Faivusovich,
V.F. Stepanova et al. - M .: Institute of Information and Information Center "TIMR",
2016. - 103 p.
[6]
Fedosov S.V., Rumyantseva V.E., Khrunov V.A. Mathematical modeling of mass transfer
in the processes of corrosion of concrete to ensure the safety and durability of buildings
and structures // Actual problems of drying and thermo-moisture treatment of materials in
various industries and agro-industrial complex: a collection of scientific articles of the
First International Lykovsky scientific readings dedicated to the 105th anniversary of
academician A.V. Lykov. - 2015. - p. 260-262.
[7]
Karpenko N.I., Karpenko S.N., Yarmakovsky V.N., Erofeev V.T. Modern methods of
ensuring the durability of reinforced concrete structures // ACADEMIA. RAAC - M.,
2015. - № 1. - p. 93-102.
[8]
Elchishcheva, T.F. Dynamics of the content of impurities in the air of the Central Black
Earth region for the design of external enclosing structures of buildings // Housing
construction. - 2016. - №6. - pp. 48-51.
[9]
Erofeev V.T., Smirnov V.F., Morozov E.A. and others. Microbiological destruction of
materials. - M .: DIA, 2018. - 128 p.
http://www.iaeme.com/IJCIET/index.asp
634
[email protected]