Biogenic sulfuric acid attack on different types of commercially produced concrete sewer pipes

The degradation of concrete due to ingress of sulfate ions from the environment plays an important role in the durability of concrete constructions. Microbiologically induced concrete corrosion (MICC) damages especially sewage collection systems. The most rapid cases of deterioration always occur in areas with elevated H2S concentrations, moisture, and oxygen in the atmosphere. During the MICC, the pH of the surface of concrete sewer pipes is reduced and it may lead to the steel depassivation and results in the corrosion of steel reinforcement. Damage due to a sulfate interaction can result in a cracking and softening, with a loss of strength of concrete. The formation of ettringite (AFt) from gypsum (forming by reaction of sulfate anion with calcium hydroxide) and C3A via monosulfate (AFm) is the main chemical reaction of sulfate attack on concrete. Ettringite and gypsum have considerably larger volume than initial compounds, which leads to increased pressure in concrete. This paper is focused on the sulfate attack on fine-grained concrete where the effect of 0.5% sulfuric acid, simulating MICC, and a solution simulating sewage water has been investigated on changes of the pH, content of sulfates and the porosity in various types of concrete. The aim of this study is to compare the changes in different types of concrete during the sulfate attack in two kinds of medium represented the bottom part of pipelines (waste water) and the sewer crown (0.5% H2SO4). It was found, that after 1 year in 0.5% H2SO4, a visible degradation of surface occurs in all investigated types of concrete. Samples over the year in waste water became dark. Concentration of sulfates in all studied types of concrete increased six times at least after one year sulfuric acid attack and also the reduction of the pH of their aqueous leaches was determined. The solution simulating sewage water did not cause such changes.

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Accelerated performance evaluation of repair mortars for concrete sewer pipes subjected to sulfuric acid attack

Journal of Materials Research and Technology ◽

10.1016/j.jmrt.2020.09.124 ◽

2020 ◽

Vol 9 (6) ◽

pp. 13635-13645

Author(s):

Han Byeol Chang ◽

Young Cheol Choi

Keyword(s):

Performance Evaluation ◽

Sulfuric Acid ◽

Acid Attack ◽

Sewer Pipes ◽

Repair Mortars

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Experimental research and prediction of the effect of chemical and biogenic sulfuric acid on different types of commercially produced concrete sewer pipes

Cement and Concrete Research ◽

10.1016/j.cemconres.2004.02.015 ◽

2004 ◽

Vol 34 (12) ◽

pp. 2223-2236 ◽

Cited By ~ 130

Author(s):

N. De Belie ◽

J. Monteny ◽

A. Beeldens ◽

E. Vincke ◽

D. Van Gemert ◽

...

Keyword(s):

Sulfuric Acid ◽

Experimental Research ◽

Sewer Pipes ◽

Different Types

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Comparison of Different Magnesium Hydroxide Coatings Applied on Concrete Substrates (Sewer Pipes) for Protection against Bio-Corrosion

Water ◽

10.3390/w13091227 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1227

Author(s):

Domna Merachtsaki ◽

Eirini-Chrysanthi Tsardaka ◽

Eleftherios K. Anastasiou ◽

Haris Yiannoulakis ◽

Anastasios Zouboulis

Keyword(s):

Sulfuric Acid ◽

Magnesium Hydroxide ◽

Concrete Surface ◽

Sem Analysis ◽

Acid Attack ◽

Sewer Pipes ◽

Surface Ph ◽

Adhesion Ability ◽

Coating Mass ◽

Surface Morphologies

Several coatings and linings have been examined and used for the protection of sewer concrete pipes, against mainly biogenic-provoked corrosion due to the production of bio-sulfuric acid, leading to the degradation of the pipes’ structure and eventually, to their collapse and need for costly replacement. This study aimed to examine the potential differences between five different magnesium hydroxide coatings, prepared from powders presenting different purity, surface area and pore size distribution, when applied as corrosion protection agents. These coatings were tested by using accelerated sulfuric acid spraying tests, both in dry and wet coating conditions. The coating adhesion ability and their microstructure were examined by the application of pull-off measurements and of SEM analysis, respectively and were found to present certain differences, regarding the adhesion ability and the surface morphologies. During the acid spraying procedure, the surface pH and the mass change of coated concrete specimens were recorded daily. The surface pH was reduced towards acidic values and the mass reduction approached almost −20% in comparison with the initial coating mass for certain cases. Additionally, the hardness and roughness of concrete surface under the coating layer (i.e., the interface between the coating and the surface) after four days of acid spraying, exhibited much smaller changes (due to protection) in contrast to the uncoated concrete specimens (used as blank/comparison experiments), which were found to be highly affected/corroded. The formation of concrete corrosion and coating by-products, as noticed after the respective chemical reactions, was recorded by X-ray diffraction (XRD) measurements and the respective quantification of obtained results. In all the coated specimens only very small amounts of the major by-product (gypsum) was observed, indicating that the concrete surface was sufficiently protected from sulfuric acid attack.

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Modelling of the sulfuric acid attack on different types of cementitious materials

Cement and Concrete Research ◽

10.1016/j.cemconres.2018.01.014 ◽

2018 ◽

Vol 105 ◽

pp. 126-133 ◽

Cited By ~ 11

Author(s):

Anaïs Grandclerc ◽

Patrick Dangla ◽

Marielle Gueguen-Minerbe ◽

Thierry Chaussadent

Keyword(s):

Sulfuric Acid ◽

Cementitious Materials ◽

Acid Attack ◽

Different Types

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Sulfuric Acid Attack on Various Types of Fine Grained Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1100.101 ◽

2015 ◽

Vol 1100 ◽

pp. 101-105

Author(s):

Martin Vyšvařil ◽

Markéta Rovnaníková

Keyword(s):

Sulfuric Acid ◽

Acid Corrosion ◽

Sulfate Attack ◽

Steel Reinforcement ◽

Acid Attack ◽

Sewer Pipes ◽

Sulfate Ions ◽

Fine Grained ◽

Ph Values ◽

Sulfuric Acid Corrosion

Sulfate corrosion is one of the major threats for durability of concrete constructions and it becomes a major destructor in sewage collection systems where the concrete sewer pipes are exposed to sulfates from wastewater as well as from biogenic activity of bacteria. During this process the pH of the surface of concrete sewer pipes is reduced and it may lead to steel depassivation and results in the corrosion of this steel reinforcement. This paper is focused on the sulfate attack on fine grained concrete where the effect of 0.5% sulfuric acid, simulating biogenic sulfuric acid corrosion, on changes of pH and content of sulfates in various types of concrete has been investigated. After 3 and 6 months of the corrosive treatment, the content of sulfate ions and pH values in several layers of specimens were determined. It was found that the sulfate ions penetrate into concrete to the maximum depth of 20 mm and the pH of the aqueous leaches of particular layers of the samples was reduced to 11.4 at the most. Thus, the conditions for the depassivation of reinforcement were not met. The GL and GBFS concrete samples showed the least changes of their pH and therefore they had the best resistivity to the six months sulfate attack.

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Properties and Performance of Novel Mg(OH)2-Based Coatings for Corrosion Mitigation in Concrete Sewer Pipes

Materials ◽

10.3390/ma13225291 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5291

Author(s):

Domna Merachtsaki ◽

Georgios Fytianos ◽

Efthimios Papastergiadis ◽

Petros Samaras ◽

Haris Yiannoulakis ◽

...

Keyword(s):

Sulfuric Acid ◽

Magnesium Hydroxide ◽

Low Cost ◽

Concrete Surface ◽

Initial Surface ◽

Acid Attack ◽

Sewer Pipes ◽

Surface Samples ◽

Protected Surface ◽

And Performance

The biological activity occurring in urban sewerage systems usually leads to the (biogenic) corrosion of pipe infrastructure. Anti-corrosion coating technology was developed in an effort to protect sewer pipes from degradation. This study evaluates a new class of relatively low-cost magnesium hydroxide-based coatings, regarding their ability to adhere efficiently onto the concrete surface, and offer efficient corrosion protection. Six magnesium hydroxide-based coatings were prepared with the addition of two different types of cellulose, used as adhesion additives, and these were applied on concrete specimens. Pull-off measurements showed that the addition of higher amounts of cellulose could improve the coating adhesion onto the concrete surface. An accelerated sulfuric acid spraying test was used to evaluate the consumption time of the applied coatings and their efficiency in maintaining over time slightly alkaline pH values (above 8) on the coated/protected surfaces. At the end of spraying test, a mineralogical analysis of surface samples was performed, indicating that the formation of corrosion by-products (mainly gypsum) was increased when the added amount of cellulose was lower. Hardness and roughness measurements were also conducted on the concrete surfaces, revealing that the coatings helped the concrete surface to preserve its initial surface properties, in comparison to the uncoated specimens. A SEM/microstructure analysis showed that aggregates were formed (possibly consisting of Mg(OH)2), affecting the reactivity of the protected surface against sulfuric acid attack.

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Resistance of different types of concrete mixtures to sulfuric acid

Materials and Structures ◽

10.1617/13766 ◽

2003 ◽

Vol 36 (258) ◽

pp. 242-249 ◽

Cited By ~ 11

Author(s):

J. Monteny

Keyword(s):

Sulfuric Acid ◽

Concrete Mixtures ◽

Different Types

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Preliminary Study on Gold Recovery from High Grade E-Waste by Thiourea Leaching and Electrowinning

Minerals ◽

10.3390/min11030235 ◽

2021 ◽

Vol 11 (3) ◽

pp. 235

Author(s):

Nicolò Maria Ippolito ◽

Ionela Birloaga ◽

Francesco Ferella ◽

Marcello Centofanti ◽

Francesco Vegliò

Keyword(s):

Sulfuric Acid ◽

Leach Solution ◽

High Grade ◽

Gold Dissolution ◽

Plastic Part ◽

The Third ◽

Current Consumption ◽

Different Types ◽

Preliminary Study ◽

A Current

The present paper is focused on the extraction of gold from high-grade e-waste, i.e., spent electronic connectors and plates, by leaching and electrowinning. These connectors are usually made up of an alloy covered by a layer of gold; sometimes, in some of them, a plastic part is also present. The applied leaching system consisted of an acid solution of diluted sulfuric acid (0.2 mol/L) with thiourea (20 g/L) as a reagent and ferric sulfate (21.8 g/L) as an oxidant. This system was applied on three different high-grade e-waste, namely: (1) Connectors with the partial gold-plated surface (Au concentration—1139 mg/kg); (2) different types of connectors with some of which with completely gold-plated surface (Au concentration—590 mg/kg); and (3) connectors and plates with the completely gold-plated surface (Au concentration—7900 mg/kg). Gold dissolution yields of 52, 94, and 49% were achieved from the first, second, and third samples, respectively. About 95% of Au recovery was achieved after 1.5 h of electrowinning at a current efficiency of only 4.06% and current consumption of 3.02 kWh/kg of Au from the leach solution of the third sample.

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