Forecasting the durability of reinforced concrete under conditions of microbiological corrosion

Strokin, Konstantin; Novikov, D.; Konovalova, Viktoriya

doi:10.1051/e3sconf/202127404003

Cited by 5 publications

(2 citation statements)

References 20 publications

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“…A mixture of carboxylic acids, illustrated in Table 1, was selected as a model medium to simulate the waste products of microorganisms in the pore liquid of concrete. The acid concentration was increased to 10% [35,36] in order to increase the rate of bio-damage. The samples were put in a model medium as shown in Figure 1 to determine the effect produced by an aggressive medium on the extent of damage to cement stone and concrete.…”

Section: Methodsmentioning

confidence: 99%

The Influence of the Aggressive Medium upon the Degradation of Concrete Structures: Numerical Model of Research

Ruslan,

Farid,

Rashit

et al. 2024

Buildings

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This article discusses the impact of the aggressive environment on the pattern of pore distribution, strength, and mass absorption of investigated samples. For this purpose, a physical and numerical research model has been developed based on Fick’s second law and Zhurcov’s theory. Consequently, computer tomography research revealed that pore redistribution was revealed in test samples due to exposure. The degradation model is proposed assuming that in the first stage of interaction between concrete constructions and aggressive medium, the product of interaction is accumulated in the surface of structures and pores. Interaction products in the form of needle-shaped crystals grow in time and create additional stress in the body of the structure, resulting in partial distribution of the surface of the structure due to the growth. In this state, the excretion of dissolved substances (in the form of citrate and calcium acetate), leaching of Ca(OH)2, and decalcination of CSH lead to a decrease in the strength of cement stone. Based on the developed numerical models, the dependences of aggressive environment impact on the on the parameters of the structure of cement composites at different exposure times were obtained. For the samples obtained during the activation of Portland cement in the electromagnetic mill, energy parameters of the destruction process are 1.85–2.2 times heavier than the control compositions. The samples obtained by activating Portland cement in the electromagnetic mill have a higher susceptibility to an aggressive environment (they absorb 1.8 times more energy per unit of time for structure transformation). However, the higher U-energy barrier (1.85 times greater than the control composition) provides both a longer term of exploitation and a lower kinetics of the change in the strength of the material.

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Section: Methodsmentioning

confidence: 99%

The Influence of the Aggressive Medium upon the Degradation of Concrete Structures: Numerical Model of Research

Ruslan,

Farid,

Rashit

et al. 2024

Buildings

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“…As a result of biocorrosion, the porosity of concrete increases [6,12,13] and diffusion processes accelerate, which contributes to the development of corrosion processes [14][15][16][17]. The reaction of biogenic acids and other products of the vital activity of microorganisms with the components of the cement stone of concrete leads to the destruction of the structure.…”

Section: Introductionmentioning

confidence: 99%

Increasing the Biostability of Concrete by the Introduction Of Additives

Rumyantseva,

Konovalova,

Narmaniya

et al. 2023

E3S Web Conf.

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To increase the resistance to fungal corrosion and improve the performance of concrete cement stone, it is proposed to introduce calcium stearate and active metal nitrates in an amount of 0.5% by weight of cement into the cement mixture at the manufacturing stage. To determine the degree of corrosion damage of cement stone by fungal microorganisms Aspergillus niger, porosity, density, water absorption and strength were determined. It has been found that the introduction of a hydrophobic additive of calcium stearate into the cement mixture during the manufacture of concrete reduces water absorption, reduces porosity and increases strength. Additives of nitrates of active metals do not affect the characteristics of the cement stone of concrete. As a result of 6 months of fungal corrosion, the water absorption, porosity and density of cement stone containing calcium stearate did not change, and the strength decreased by 4%. Metal nitrates do not prevent damage to the cement stone by microorganisms, but slow down the flow of aggressive substances to the surface of the reinforcement in concrete. The combined introduction of calcium stearate and nitrates into the cement mixture will improve the characteristics of concrete, increase its corrosion resistance and ensure the safety of reinforcement in concrete.

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The Influence of Microorganisms on the Physical and Mechanical Properties of Concrete

Strokin

Novikov

Konovalova

et al. 2021

Bulletin of Belgorod State Technological University Named After. V. G. Shukhov

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The article considers the change in the physical and mechanical characteristics of cement stone made of the CEM I 42,5 N Portland cement in the process of bacterial and fungal corrosion for 6 months in the air and moisture conditions. It is established that the density of concrete during microbiological corrosion increases under constant moistening of the sample. However, after drying, a decrease in the density of concrete is recorded by 10 % under the influence of Bacillus subtilis bacteria and by 14 % under the influence of black mold. The degree of influence of microorganisms on the amount of water absorption of cement stone is established experimentally. Bacteria increases water absorption by 7 %, black mold increases water absorption by 10 %. Within 6 months, water absorption increased from 21 to 24,5 % for bacterial corrosion in indoor conditions, and from 24 to 29 % for fungal corrosion. When exposed to capillary moisture for 6 months, the water absorption of concrete increased to 30,4 % under the influence of Bacillus subtilis bacteria and to 37,3% under the influence of Aspergillus niger van Tieghem fungi. An increase in the water absorption of concrete is associated with an increase in porosity due to biodegradation. Under room conditions of exposure to bacteria, the porosity increases from 14,1 to 15,3 %, and from 14,3 to 17,9 % after exposure to black mold. With constant moistening, the porosity of cement concrete increases to 19,1 and 25,6 % with bacterial and fungal corrosion, respectively. The loss of compressive strength of cement stone is 13 % under the influence of bacteria and 15 % under the influence of fungi in the air for 6 months. In case of microbiological corrosion of concrete under conditions of constant wetting, the strength decreases by about 35 % in 6 months

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Forecasting the durability of reinforced concrete under conditions of microbiological corrosion

Cited by 5 publications

References 20 publications

The Influence of the Aggressive Medium upon the Degradation of Concrete Structures: Numerical Model of Research

The Influence of the Aggressive Medium upon the Degradation of Concrete Structures: Numerical Model of Research

Increasing the Biostability of Concrete by the Introduction Of Additives

The Influence of Microorganisms on the Physical and Mechanical Properties of Concrete

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