Scholarly article on topic 'Current Trends in Investigation of Concrete Biodeterioration'

Current Trends in Investigation of Concrete Biodeterioration Academic research paper on "Civil engineering"

CC BY-NC-ND
0
0
Share paper
Academic journal
Procedia Engineering
OECD Field of science
Keywords
{Biocorrosion / concrete / "chemical analysis"}

Abstract of research paper on Civil engineering, author of scientific article — Vlasta Ondrejka Harbulakova, Adriana Estokova, Nadezda Stevulova, Alena Luptáková, Katarina Foraiova

Abstract The issue of the building materials biodeterioration has a significant economic dimension because it results in the costly repair. The start and the course of corrosion are conditioned by many factors which undoubtedly include biological effects like the influence of vegetation and microorganisms causing the so called microbial corrosion. Microorganisms have also a considerable share in the decay and degradation of different building materials. This paper presents the results of the investigation of sulphate attack on concrete samples caused by simultaneous effect of sulphur-oxidising bacteria represented by Acidithiobacillus thiooxidans and sulphate-reducing bacteria represented by Desulfovibrio desulfuricans. The experiments proceeded in model laboratory conditions as well as in situ in waste water in sewerage systems. The chemical composition changes of concrete samples, weight changes and changes in compressive strength were investigated.

Academic research paper on topic "Current Trends in Investigation of Concrete Biodeterioration"

Available online at www.sciencedirect.com

ScienceDirect

Procedia Engineering 65 (2013) 346 - 351

Concrete and Concrete Structures 2013 Conference

Current Trends in Investigation of Concrete Biodeterioration

Vlasta Ondrejka Harbulakovaa*9 Adriana Estokovab, Nadezda Stevulovab9 Alena

Luptäkoväc? Katarina Foraiovad

aTechnical Univesity ofKosice, Faculty of Civil Engineering, Institute ofEnvironmental Engineering, Department of Environmental

Engineering, Vysokoskolska 4, 042 00 Kosice, Slovakia bTechnical Univesity ofKosice, Faculty of Civil Engineering, Institute of EnvironmentalEngineering, Department of Material Engineering,

Vysokoskolska 4, 042 00 Kosice, Slovakia cSlovak Acadamy of Science, Institute of Geotechnics, Watsonova 45, 043 53 Kosice, Slovakia dEastern Slovakia Water Supply Company, Komenskeho 50, 042 01 Kosice, Slovakia

Abstract

The issue of the building materials biodeterioration has a significant economic dimension because it results in the costly repair. The start and the course of corrosion are conditioned by many factors which undoubtedly include biological effects like the influence of vegetation and microorganisms causing the so called microbial corrosion. Microorganisms have also a considerable share in the decay and degradation of different building materials.

This paper presents the results of the investigation of sulphate attack on concrete samples caused by simultaneous effect of sulphur-oxidising bacteria represented by Acidithiobacillus thiooxidans and sulphate-reducing bacteria represented by Desulfovibrio desulfuricans. The experiments proceeded in model laboratory conditions as well as in situ in waste water in sewerage systems. The chemical composition changes of concrete samples, weight changes and changes in compressive strength were investigated.

© 2013The Authors. PublishedbyElsevier Ltd.

Selectionand peer-reviewunderresponsibilityof University of Zilina,Faculty ofCivilEngineering,Department of Structures andBridges

Keywords: Biocorrosion; concrete; chemical analysis;

* Tel.: +421 55 602 4269 ; fax: +421 55 602 4331 . E-mail address: vlasta.harbulakova@tuke.sk

1877-7058 © 2013 The Authors. Published by Elsevier Ltd.

Selection and peer-review under responsibility of University of Zilina, Faculty of Civil Engineering, Department of Structures and Bridges doi:10.1016/j.proeng.2013.09.053

1. Introduction

Microorganisms are almost never found in nature as pure species and, while laboratory studies on isolated cultures are essential to the understanding of biodeterioration, the role of microbial consortia is becoming increasingly recognized [1]. Successive growth of microorganisms and their corrosive metabolic products have roles in the corrosion of concrete and protective coating materials were presented in [2]. It showed that the importance of fungi in sewer corrosion is in preparing the pipe surface for the colonisation and thus the greater corrosion action of Thiobacilli strains. The forms of corrosion which can be promoted by interaction of microorganisms with concrete are numerous, including pitting, cracking, leaching of compounds from concrete matrix, pH values of concrete changes and creation of new chemical products. The presence of various bacteria - such as the sulphur reducing and proteolytic bacteria in the sewer - together with animal and plant wastes is the main reason for the corrosion of concrete [3]. One of the often occurred deleterious processes in concrete in relation to alkali carbonate reaction is sulphate attack. Sources of sulphate which can cause sulphate attack include groundwater, seawater, wastewater [4] oxidation of sulfide minerals in clay adjacent to the concrete, pollution from industrial waste and masonry, where sulphates are present in some bricks and can be gradually released over a long period of time, causing sulphate attack the mortar, especially where sulphates are concentrated due to moisture movement [5].

A special type of sulphate deterioration of concrete materials is biocorrosion - the process caused by presence and activities of microorganisms producing sulphuric acid. The biogenic sulphuric acid is generated by complex mechanisms and various microbial species, particularly ferrous and sulphur oxidizing bacteria genera Acidithiobacillus. There are five species of Acidithiobacillus spp. that play important roles on corroded and corroding concrete: T. thioparus, T. novellus, T. neapolitanus, T. intermedius and Ac. thiooxidans. The first four species listed are neutrophilic sulfur-oxidizing microorganisms (NSOM). The last species listed is an acidophilic sulfur-oxidizing microorganism (ASOM) [6]. Fungi have also recently been found to be involved in the corrosion processes [7]. The colonization of the concrete is an excellent example of microbial succession. Once the pH of the concrete surface is reduced to 9 and with sufficient nutrients, moisture and oxygen, some species of sulphur bacteria like Acidithiobacillus spp. mentioned above can attack the concrete surface and reproduce [8].

This paper presents the particular results of the experiments focused on the simulation of sulphate-based biocorrosion on concrete samples under laboratory condition as well as on bio-corrosion in situ.

2. Material and Methods

Concrete samples of various compositions were prepared for the experiments: standard concrete mixture without any additives and mixture with 10 % replacement of cement by coal fly ash. The more detailed information about the mixtures composition and coal fly ash chemical analysis are presented in our previous works [9,10]. Cubic (150x150x150 mm) and cylindrical (25 mm in diameter and 20 mm in height) concrete samples were used in the experiments. Cylinder concrete samples were formed as a drilled core from concrete cube using drilling mechanisms STAM. Prepared concrete samples were investigated against simultaneous effect of sulphate - reducing bacteria SRB {Desulfivibrio spp.) and Acidithiobacillus thiooxidans.

First set of samples has been tested by laboratory simulation of biocorrosion and second part of samples has been tested in situ.

Laboratory simulation experiments proceeded during 90 days and are described in more details in our previous papers [11]. Sulphur oxidizing bacteria Acidithiobacillus thiooxidans were isolated from the mixed culture obtained from the mine water (the shaft Pech, the locality Smolnik, Eastern Slovakia) and the selective nutrient medium 9K was used for the isolation and cultivation of them. Optimal growth temperature was 28 - 30oC and pH has been in 2.0 - 3.5 range. Sulphate-reducing bacteria Desulfovibrio spp. used in the experiment were isolated from a mixed culture obtained from the potable mineral water (Gajdovka spring, the locality Kosice-north, Slovakia). The selective nutrient medium DSM-63 (Postgate, 1984) was used for isolation and cultivation of these bacteria. Optimal growth conditions were: pH range from 6.5 to 7.3 and temperature range of 30 - 37 °C (mezofilic) and 50 -70 °C (thermofilic).

In situ experiments proceeded by immersion of concrete samples into the waste water of sewerage system in city ofKosice for 3 (cylinder samples) and 6, 12 and 18 months (cube samples - Fig. 1). The parameters of wastewater from gravitational combined sewage system (domestic and storm water) were tested in Laboratories of Waterwater in Koksov Baksa, Eastern Slovakia Water Supply Company [12].

^^^SS^y m

Fig. 1. Concrete samples prepared for sewer system experiment.

The weight changes, chemical composition and compressive strength of tested concrete samples were investigated. The weight changes of concrete samples were determined by gravimetric method measured by analytical balance within 0.00001 g. The chemical composition of samples before and after the experiments was measured by X-ray florescence analysis (XRF) using SPECTRO iQ II (Ametek, Germany) with SDD silicon drift detector with resolution of 145 eV at 10 000 pulses. The strength parameters were tested by using the ELE ADR 2000 equipment.

3. Results and Discussion

The results of the weight changes of concrete samples after the laboratory experiments are illustrated in Fig. 2. The concrete samples with coal fly ash (10 %) and without coal fly ash addition (0 %) were compared after the exposition to the bacterial environment (BC) and distilled water (DW).

14.10 14.00 13.90 13.80 13.70 13.60 13.50 13.40 13.30 13.20

□ DW

before

before

Fig. 2. (a) weight changes of concrete samples before and after biocorrosion experiment; (b) weight changes of reference concrete samples before

and after control experiment (distilled water).

Decreases in weight for both samples with coal fly ash (10 %) and without coal fly ash addition (0 %) studied in biocorrosion experiment were observed after the exposition to the bacterial environment (BC) - Fig. 2a. In case of sample without coal fly ash decrease in weight has been measured to be0.4g and in case of sample with coal fly ash replacement it has been 0.09 g, what represents 2.85 % and 0.66 % respectively. In case of samples exposed to the distilled water no significant changes were observed for both types of samples.

In Table 1 results of weight changes from in situ experiments are presented.

Table 1. The weight changes of concrete samples.

weight before weight after change of

experiment [g] experiment [g] weight [%]

reference sample (0 %) 28.26 28.3 Î3.67

fly ash replacement (10%) 26.67 26.89 Î0.81

On the contrary to the laboratory experiments, the increase of weight was observed for both samples in experiments on site. The weight change for sample without coal fly ash replacement represented almost 4 %, for sample with 10 % of fly ash replacement only 0.8 % increase was measured.

The content of the basic components of concrete samples was determined by using X-ray fluorescence analysis (XRF). In Fig. 3, the changes in concentrations of basic chemical components of concrete sample with coal fly ash tested in laboratory condition are illustrated.

Fig. 3. Chemical composition of concrete samples with fly ash addition before (a) and after the laboratory experiments(b).

The decrease in concentrations of Si02 and CaO was observed after the laboratory experiments for both concrete samples with (Fig. 3) and without coal fly ash. Both increase and decrease of the other components concentrations was measured for both samples after the experiments.

50.00 40.00 30.00 20.00 10.00 0.00

before after

□ Si02 ■ CaO

£8.00 8*

I 6.00

4.00 2.00 0.00

|j|. IlUIb-J

before | after 10%

before | after 0%

■ Na20

□ MgO

■ A1203

■ P205

□ S03

■ CI

□ Ti02

□ MnO

□ Fe203

Fig. 4. Chemical composition of concrete samples before (a) and after in situ experiment (b).

The comparison of the chemical composition of samples with (10 %) and without coal fly ash (0 %) before and after 3 months of wastewater exposition in real conditions is illustrated in the Figure 4.

As it is shown in Fig. 4 percentage decrease of chemical components (AI2O3, SiÛ2, MgO, CaO) was noticed in case of samples with cement replacement. Percentage increase of chemical components for the same samples was measured for Fe203. In case of samples without cement replacement chemical content of AI2O3, CaO, MgO, Si02 as well as Fe2Û3 increased.

The results of the concrete cubes (with 0% of coal fly ash) compressive strength measurements are presented in Table 2. Initial value of the compressive strength was 45 MPa.

Table 2. Changes in compressive strength compare to the initial value of reference sample.

Compressive Compressive

strength after strength

experiment changes during

[MPa] experiment [%]

6 months 57.9 Î28.67

12 months 75.65 Î24.11

18 months 52.5 430.66

Compressive strength increases of concrete samples after 6 and 12 months were observed for samples exposed to waste water comparing to initial compressive strength of reference samples. In case of sample after 18 month aggressive exposition noticeable decrease was measured (more than 20 MPa). Concrete samples were prepared as high-performance concrete that is likely why the compressive strength showed the enormous increase resulted in continuing hydration processes during exposition to waste water. After the value of compressive strength reached the critical point, the concrete led to disintegration. Corrosion processes was clearly manifested after 18 months of exposition and it led to more than 30 % decrease of compressive strength when compared to samples placed to wastewater for 12 months. All samples were evaluated according to the STN EN 206 [13].

4. Conclusion

The results of the weight changes of experiment proceeded in laboratory conditions shown that samples with coal fly ash replacement are seems to be more resistant for leaching components from the concrete matrix. For reference samples exposed to the distilled water measured weight changes were not significant in case of both tested samples.

In case of sample without coal fly ash replacement visible increases of AI2O3 content in concrete matrix and Fe2Û3 were noticed. Also the increase of SO3 in the chemical composition of sample with fly ash replacement was noticed. For better understanding more detailed study is in progress.

The concrete samples deterioration was investigated also in the real conditions of wastewater in sewerage system in Kosice city, Slovakia during 18 months. Exposition for 18 months in wastewater seems to be enough for the concrete deterioration process starting resulted in compressive strength decrease by 23.62 MPa when compared to the 12 months exposition.

Acknowledgements

The research has been carried out within the Grant No. 2/0166/11 of the Slovak Grant Agency for Science. References

[1] I. B.Beech, C.C. Gaylarde, Recent advances in the study of biocorrosion - an overview, Revista de Microbiologia 30, 1999, p.177-190.

[2] M. Valix, D. Zamri, H. Mineyama, W.H. Chueng, J. Shi, H. Bustamante, Microbially induced corrosion of concrete and protective coatings in gravity sewers, Chinese Journal of Chemical Engineering 20 (3), 2012, p. 433-438.

[3] A.K. Parande, P.L. Ramsamy, S. Ethirajan, C.R.K. Rao, N. Palanisamy, Deterioration of reinforced concrete in sewer environments, Municipal Engineer 159, Issue MEI, 2006, p. 11-20.

[4] H. Ghoualem, Assesment of Wastewater and treatment by the Lagoon Process, Chemical Engineering Transaction 17, 2009, p. 391-396.

[5] N. Winter, Understanding Cement, WHD Microanalysis Consultants Ltd, United Kingdom, 2009, p. 182.

[6] D. Nica, J.L. Davis, L. Kirby, G. Zuo, D.J. Roberts, Isolation and characterization of microorganisms involved in the biodeterioration of concrete in sewers, International Biodeterioration & Biodégradation 46, 2000, p. 61-68.

[7] J. D. Gu, T.E. Ford, N.S. Berke, R. Mitchell, Biodeterioration of concrete by the fungus Fusarium, International Biodeterioration & Biodégradation 41, 1998, p. 101-109.

[8] T. Mori, T. Nonaka, K. Tazaki, M. Koga, Y. Hikosaka, S. Noda, Interactions of nutrients, moisture, and pH on microbial corrosion of concrete sewer pipes, Water Research 26, 1992, p. 29-37.

[9] A. Estokova, V. Ondrejka Harbulakova, A. Luptakova, N. Stevulova, Study of the deterioration of concrete influence by biogenic sulphate attack, Procedia Engineering 42, 2012, p. 1901-1908.

[10] A. Luptakova, M. Prascakova, A. Estokova, N. Stevulova, V. Ondrejka Harbulakova, Influence of bacteria on building composites materials contained of energetic waste, 12th International Conference on Environmental Science and Technology (CEST 2011), Rhodes Island, Greek, 2011, p.1-6.

[11] V. Harbulakova, A. Estokova, A. Luptakova, N. Stevulova, G. Janak, Concrete specimens biodeterioration by bacteria Acidithiobacillus thiooxidans and Desulfovibrio genera, Pollack Periodica 4 (1), 2009, p. 83-92.

[12] V. Ondrejka Harbulakova, A. Estokova, N. Stevulova, The investigation of concrete biodeterioration in sewer pipes-case study, Pollack Periodica 5 (1), 2010, p.87-95.

[13] STN EN 206-1 Concrete: Part I.: Specification, Properties, Made of Production and Conformity, 2004.