Biological Corrosion of Concrete

2020 ◽  
Vol 786 (11) ◽  
pp. 13-23
Author(s):  
V.T. EROFEEV ◽  
◽  
SALMAN Al-DULAIMI SALMAN DAVUD ◽  
A.P. FEDORTSOV ◽  
A.D. BOGATOV ◽  
...  
Keyword(s):  
Cement Stone ◽  
Vital Activity ◽  
Cement Concrete ◽  
Biological Resistance ◽  
Biogenic Substances ◽  
Biogenic Carbon ◽  
Biological Corrosion ◽  
The Impact ◽  
Subsequent Decomposition ◽  
Intensive Growth

The article considers the results of studies to determine the causes, mechanisms and features of biological corrosion of cement concrete. It has been found that the intensive growth of microorganisms on the surface and in the pores of concrete leads to the formation of corrosive biogenic substances and, as a result, the reduction of alkalinity of cement stone with its subsequent decomposition. The influence of certain types of biogenic substances on the components of cement concrete (biogenic organic acids, biogenic carbon dioxide, biogenic nitric acid, biogenic hydrogen sulphide and sulfuric acid) is considered. Methods for increasing the biological resistance of concrete are described, such as: adding additives that can form buffer systems capable of reducing the impact on cement concretes of acids produced by microorganisms; treating the surface of composites with substances capable of repelling microorganisms and environments necessary for their vital activity; use of active media capable of forming dense and inert layers on the surface of the material. Despite the available methods of increasing the biological resistance of cement concrete, it is not possible to fully guarantee their safety from biocorrosion, at least because microorganisms can adapt to the environment and suspend the effect of protection. In this regard, the work attempts to assess and predict the biological resistance of the material.

Resistance of Binding Systems of Various Compositions to the Action of Molds

2020 ◽  
Vol 786 (11) ◽  
pp. 41-46
Author(s):  
V.V. STROKOVA ◽  
◽  
V.V. NELUBOVA ◽  
M.N. SIVALNEVA ◽  
M.D. RYKUNOVA ◽  
...  
Keyword(s):  
Aging Process ◽  
Building Materials ◽  
Environmental Safety ◽  
Fungal Resistance ◽  
Building Structures ◽  
Vital Activity ◽  
Regulatory Documents ◽  
Living Organisms ◽  
Biological Corrosion ◽  
Test Objects

The dynamic development of urbanization contributes to an increase in emissions of industrial waste, which is the cause dysfunction of the ecosystem balance and leads to the development of biological corrosion on building materials associated with the products of the vital activity of microorganisms. In this regard, it is necessary to assess the resistance of composites to predict the durability of building structures under conditions of biological influence of microorganisms. Binder systems of various compositions were studied: cementless nanostructured binders (NB) based on quartz sand and granodiorite, gypsum, Portland cement and alumina cement. The toxicity of binders was assessed by biotesting on living organisms – cladocerans Daphnia Magna – according to the criteria of the intensity of their growth and viability. As a result, the high environmental safety of NB is substantiated, and the ranking of the studied binders according to the degree of increase in their toxicity to test objects is presented. Fungal resistance was assessed by the ability of molds for growing and reproduction on the studied samples. It was found that the most active in terms of the development of binders were representatives of the genus Aspergillus, the intensity of growing of which in all variants did not decrease below 3 points. Gypsum and NB were especially vulnerable, where the degree of fouling repeatedly reached 5 points. Even the initially biostable cement, after the aging process, lost its stability at different extent. The obtained results indicate the need to increase the resistance of composites for various purposes under conditions of biocorrosion at the stage of design and updating of regulatory documents, including tests for fungal resistance in the list of mandatory.

scholarly journals POROSITY PARAMETERS OF CEMENT STONE CONTAINING CHEMICAL ADMIXTURES OF DIFFERENT PURPOSE / CEMENTINIO AKMENS SU SKIRTINGOS PASKIRTIES CHEMINIAIS PRIEDAIS PORINGUMO RODIKLIAI

2013 ◽  
Vol 5 (5) ◽  
pp. 530-535
Author(s):  
Lukas Venčkauskas ◽  
Mindaugas Daukšys
Keyword(s):  
Cement Paste ◽  
Cement Stone ◽  
Hardened Cement ◽  
Closed Porosity ◽  
Hardened Cement Paste ◽  
Chemical Admixtures ◽  
Average Size ◽  
The Impact ◽  
Plasticizing Admixture

The conducted research has established a complex influenceand the impact of separate chemical admixtures of differentpurpose on the parameters of the porosity of hardened cementpaste such as open and closed porosity, the average size of poresand the rates of pore inequality. According to the parametersof the porosity of hardened cement paste, on the basis of A. E.Sheikin’s methodology, the number of freezing-thawing cycleswas predicted. This research used plasticizing, viscosity modifyingand antifoaming admixtures. It has been found that, when theamount of plasticizing admixture in cement paste (W/C–0.45) isconstant and makes 1.1% of the cement mass, and the amountof viscosity modifying and antifoaming the admixture increasesfrom 0.1 to 0.6% and from 0.05 to 0.3% respectively, the openporosity of hardened cement paste varies between 30.21% and31.06%, while closed porosity varies between 5.39% and 6.22%.When the amount of the plasticizing admixture in cement paste(W/C–0.45) exceeds 1.1% of the cement mass, the open porosityof hardened cement paste increases by 1.4 times and closedporosity decreases by 2.5 times. While adding 0.1% of the viscositymodifying admixture to cement paste, the open porosityof hardened cement paste is increased by 1.5 times and closedporosity decreases by 2.4 times. The amount of 0.05% of thecement mass of the antifoaming admixture results in the increasedopen porosity of hardened cement paste by 1.5 times and reducedclosed porosity by 3.5 times. Santrauka Tyrimo metu nustatyta kompleksinė bei atskirų skirtingos paskirties cheminių priedų įtaka cementinio akmens poringumo rodikliams – atvirajam ir uždarajam poringumui, vidutinio porų dydžio ir porų vienodumo rodikliams. Tyrimuose naudoti cheminiai priedai: plastifikuojantis, klampą modifikuojantis ir mišinyje susiformavusias oro poras suardantis priedas. Nustatyta, kad cemento tešloje (V/C – 0,45) esant pastoviam plastifikuojančio priedo kiekiui – 1,0 % cemento masės, klampą modifikuojančio priedo kiekiui kintant nuo 0,1 iki 0,6 %, o mišinyje susiformavusias oro poras suardančio priedo kiekiui kintant nuo 0,05 iki 0,3 %, cementinio akmens atvirasis poringumas svyruoja nuo 30,21 iki 31,06 %, o uždarasis – nuo 5,39 iki 6,22 %. Cemento tešloje viršijus plastifikuojančio priedo 1,1 % cemento masės, cementinio akmens atvirasis poringumas padidėja apie 1,4 karto, o uždarasis poringumas sumažėja apie 2,5 karto. Pridėjus į tešlą 0,1 % cemento masės klampą modifikuojančio priedo, cementinio akmens atvirasis poringumas padidėja apie 1,5 karto, uždarasis poringumas sumažėja apie 2,4 karto. Oro poras suardančio priedo kiekis 0,05 % cemento masės cementinio akmens atvirąjį poringumą padidina apie 1,5 karto, uždarąjį poringumą sumažina apie 3,5 karto.

Regulation Of The Resistance Of Cement Concrete With Polymer Additive And Activated Liquid Medium

2021 ◽  
Vol 03 (04) ◽  
pp. 172-177
Author(s):  
Zebuniso Asrorovna Abobakirova ◽  
Keyword(s):  
Liquid Medium ◽  
Cement Stone ◽  
Polymer Additive ◽  
Capillary Porosity ◽  
Cement Concrete

The article presents the results of studies of cement concrete with a polymer reagent and an activated (magnetically treated) liquid medium. A decrease in the total and capillary porosity of the cement stone and an increase in microporosity up to 18% indicate an increase in the resistance of concrete in aggressive environments.

MATHEMATICAL MODELING OF CONCRETE STRUCTURE CORROSION IN BIOLOGICALLY AGGRESSIVE ENVIRONMENTS

2021 ◽  
Vol 3 (102) ◽  
pp. 55-67
Author(s):  
VARVARA E. RUMYANTSEVA ◽  
SVETLANA A. LOGINOVA ◽  
NATALIA E. KARTSEVA
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Parabolic Type ◽  
Cement Concrete ◽  
Mass Conductivity ◽  
Kinetics And Dynamics ◽  
Biological Corrosion ◽  
First Time ◽  
Fourth Kind

In the aquatic environment, biocorrosion is an important factor affecting the reliability and durability of concrete structures. The destruction of cement concretes during biological corrosion is determined by the processes of mass transfer. The article presents the development of a calculated mathematical model of liquid corrosion in cement concrete, taking into account the biogenic factor. For the first time, a model of mass transfer in an unbounded two-layer plate is considered in the form of differential equations of parabolic type in partial derivatives with boundary conditions of the second kind at the interface between concrete and liquid and of the fourth kind at the interface between concrete and biofilm. The results of a numerical experiment are presented to study the influence of the coefficients of mass conductivity and mass transfer on the kinetics and dynamics of the process.

scholarly journals Monitoring of Thermal and Moisture Processes in Various Types of External Historical Walls

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 505 ◽  
Author(s):  
Dariusz Bajno ◽  
Lukasz Bednarz ◽  
Zygmunt Matkowski ◽  
Krzysztof Raszczuk
Keyword(s):  
Masonry Wall ◽  
Design Guidelines ◽  
Masonry Walls ◽  
Historical Buildings ◽  
Wall Structures ◽  
Mutual Comparison ◽  
Energy Audits ◽  
Biological Corrosion ◽  
Comfort Parameters ◽  
The Impact

In order to create and make available the following: Design guidelines, recommendations for energy audits, data for analysis and simulation of the condition of masonry walls susceptible to biological corrosion, deterioration of comfort parameters in rooms, or deterioration of thermal resistance, the article analyzes various types of masonry wall structures occurring in and commonly used in historical buildings over the last 200 years. The summary is a list of results of particular types of masonry walls and their mutual comparison. On this basis, a procedure path has been proposed which is useful for monitoring heat loss, monitoring the moisture content of building partitions, and improving the hygrothermal comfort of rooms. The durability of such constructions has also been estimated and the impact on the condition of the buildings that have been preserved and are still in use today was assessed.

Quality Control of Portland Cement Concrete Slabs with Wave Propagation Techniques

1996 ◽  
Vol 1544 (1) ◽  
pp. 91-98
Author(s):  
Soheil Nazarian ◽  
Deren Yuan ◽  
Mark R. Baker
Keyword(s):  
Quality Control ◽  
Wave Propagation ◽  
Surface Wave ◽  
Portland Cement ◽  
Body Wave ◽  
Field Testing ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Impact Echo ◽  
The Impact

Coring is normally done to monitor the thickness and quality of portland cement concrete (PCC) slabs during construction. Because this procedure requires a considerable amount of time, it is done at widely spaced intervals. As a result, the most critical points, in terms of strength or thickness, are sometimes not tested. Their repeatability and extreme sensitivity to the properties of surface layer enable wave propagation techniques to be used for quality control. The main advantage of these techniques is that they are nondestructive. Fortunately, these techniques have been automated in the last few years. Two seismic devices (seismic pavement analyzer and a portable version of it called the Lunch Box) have been used extensively for quality control. With them, slabs can be tested at closely spaced points and at a fraction of the cost and time of coring. The main tests used are the impact echo for determining the thickness of the slab, the ultrasonic body wave for determining the modulus, and the ultrasonic surface wave (an offshoot of the spectral analysis of surface waves method) also for determining the modulus. On the basis of extensive field testing on many types of base and subgrade, the techniques in general—and the two devices in particular—are suitable for many quality-control projects. It was found that the most robust method for determining the modulus is the ultrasonic surface wave. The impact echo also works well, as long as enough contrast exists between the properties of the PCC and the underlying materials.

Fine Grain Concrete on Mixing Water Activated in Cavitation Permanent Magnet-Type Apparatus

2019 ◽  
Vol 816 ◽  
pp. 279-284 ◽  
Author(s):  
Marina A. Akulova ◽  
T.E. Slizneva ◽  
P.B. Razgovorov ◽  
Alla G. Sokolova
Keyword(s):  
Bending Strength ◽  
Magnetic Treatment ◽  
Cement Stone ◽  
Porous Space ◽  
Sodium Thiosulphate ◽  
Freeze Thaw ◽  
Fine Grain ◽  
The Impact ◽  
Mixing Water ◽  
Magnetic Activation

The authors obtained fine grain concrete based on the mortars of additives-electrolytes undergone mechanic magnetic activation and characterized by improved compression and bending strength and enhanced freeze-thaw resistance. There was investigated the impact of mechanic magnetic activation (MMA) on mixing water when adding calcium chloride and sodium thiosulphate as well as on porosity of cement stone and specific features of phase formation in cement stone. It was stated by the authors that MMA facilitates formation of nucleation centers in activated water in the presence of additives-electrolytes, optimization of porous space as well as crystallization of calcium carbonate in the form of aragonite when lowering the content of Portlandite. The mechanism of joined influence of hydrodynamic and magnetic treatment of mixing water has been determined.

The Study of Cement Concrete with Improved Properties Based on the Use of Astivated Silica Fume

2020 ◽  
Vol 992 ◽  
pp. 228-232
Author(s):  
E. Tkach ◽  
V. Soloviev ◽  
R. Temirkanov ◽  
Denis B. Solovev
Keyword(s):  
Large Scale ◽  
Positive Influence ◽  
Cement Stone ◽  
Chemical Characteristics ◽  
Structure Modification ◽  
Cement Concrete ◽  
Modification Process ◽  
Physico Chemical ◽  
Scale Levels

In this research the questions of microsilica usage and ways of its activation for modification of structure of cement stone and cement on its basis. The actual questions corresponding any type of filler, particularly microsilica are: how and how much should be put, which mechanisms are involving to process of structuring, how much is received result of structure modification and others. Therefore the role of microdispersed fillers in modification process of cement rock and cement on its basis must be viewed in connection with other dimensional inclusions on different large-scale levels. Reducing of concrete consumption by its substitution by microsilica, has a positive influence to physico-chemical characteristics of concrete.

scholarly journals Interlaminar Bonding Properties on Cement Concrete Deck and Phosphorous Slag Asphalt Pavement

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1427 ◽  
Author(s):  
Guoping Qian ◽  
Shunjun Li ◽  
Huanan Yu ◽  
Xiangbing Gong
Keyword(s):  
Bridge Deck ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Fine Aggregate ◽  
Cement Concrete ◽  
Bonding Properties ◽  
The Impact ◽  
Phosphorous Slag ◽  
Bridge Deck Pavement ◽  
Concrete Deck

The slippage damage caused by weak interlaminar bonding between cement concrete deck and asphalt surface is a serious issue for bridge pavement. In order to evaluate the interlaminar bonding of cement concrete bridge deck and phosphorous slag (PS) asphalt pavement, the shear resistance properties of the bonding layer structure were studied through direct shear tests. The impact of PS as a substitute of asphalt mixture aggregate, interface characteristics, normal pressure, waterproof and cohesive layer types, temperature and shear rate on the interlaminar bonding properties were analyzed. The test results indicated that the interlaminar bonding of bridge deck pavement is improved after asphalt mixture fine aggregate was substituted with PS and PS powder, and the result indicated that the shear strength of grooved and aggregate-exposed interfaces is significantly higher than untreated interface, the PS micro-powder or anti-stripping agent can also improve the adhesion between layers when mixed into SBS asphalt. This study provided important theoretical and practical guidance for improving the shear stability of bridge deck pavement.

Research on Effects of Inhibitors on Anti-Corrosion Performance of Reinforced Bar in the Concrete

2011 ◽  
Vol 239-242 ◽  
pp. 1195-1198 ◽  
Author(s):  
Liu Bin Song ◽  
Dao Wu Yang ◽  
Zhong Liang Xiao ◽  
Feng Zhang
Keyword(s):  
Open Circuit Potential ◽  
Electrode Array ◽  
Open Circuit ◽  
Reinforcing Bars ◽  
Corrosion Performance ◽  
Cement Concrete ◽  
Corrosive Media ◽  
Reinforcing Bar ◽  
Wire Beam Electrode ◽  
The Impact

The corrosion behavior of reinforcing bars in concrete was studied by simulating the 4×4 wire-beam electrode array. Different inhibitors were added to reinforced concrete. By measuring the open-circuit potential of an iron wire, the impact of different inhibitors on the corrosion of rebar in the concretes was studied after immersion in NaCl solution. The result showed that best protection was achieved by adding NaNO2 and aniline as inhibitors jointly to the concrete, as this combination maintained the open-circuit potential within the passivation range at all times, so ensuring the integrity of the passive membrane. By addition of this combination of the inhibitors, the compactibility of the cement concrete structure can be increased, thereby protecting the reinforcing bar against the external corrosive media.

Sign in / Sign up

Export Citation Format

Share Document