Sulfate Attack on Different Types of Concrete in Media Simulating Sewer System

2016 ◽  
Vol 714 ◽  
pp. 122-127
Author(s):  
Martin Vyšvařil ◽  
Markéta Rovnaníková ◽  
Patrik Bayer
Keyword(s):  
Waste Water ◽  
Sulfuric Acid ◽  
Sewage Water ◽  
Sulfate Attack ◽  
Acid Attack ◽  
Bottom Part ◽  
Sewer Pipes ◽  
Fine Grained ◽  
Different Types ◽  
One Year

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.

Study of Fine-Grained Composites Exposed to Sulfuric Acid and Sodium Sulfate

2016 ◽  
Vol 827 ◽  
pp. 275-278
Author(s):  
Martin Vyšvařil ◽  
Markéta Rovnaníková
Keyword(s):  
Waste Water ◽  
Sulfuric Acid ◽  
Sodium Sulfate ◽  
Sulfate Attack ◽  
Sewer Pipes ◽  
Sulfate Ions ◽  
Fine Grained ◽  
One Year ◽  
Corrosion Of Steel ◽  
Loss Of Strength

The degradation of concrete due to ingress of sulfate ions from the environment plays an important role in the durability of concrete constructions, especially in sewage collection systems where concrete sewer pipes are exposed to sulfates from waste water and from biogenic activity of bacteria. During this process 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 sulfate interaction can result in the cracking and softening, with loss of strength of concrete. This paper is focused on the sulfate attack on fine-grained concrete where the effect of one-year contact of 0.5% H2SO4, and 5% Na2SO4 on changes of pH and content of sulfates in 7 types of concrete has been analyzed. It was found that after one year of sulfate attack on concrete, significant growth of content of sulfates is observed in the lowermost layer of the samples. Samples treated by 5% Na2SO4 contain slightly more sulfates in the upper layers than samples treated by sulfuric acid. The reduction in pH of aqueous leaches occurred in all layers of the samples. However, even in the lower layers of the samples, the reduction of pH below 9.5 did not turn up (except for SRS sample), and thus the conditions for the depassivation of reinforcement were not met.

Sulfuric Acid Attack on Various Types of Fine Grained Concrete

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.

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

2010 ◽  
Vol 40 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Ma. Guadalupe D. Gutiérrez-Padilla ◽  
Angela Bielefeldt ◽  
Serguei Ovtchinnikov ◽  
Mark Hernandez ◽  
Joann Silverstein
Keyword(s):  
Sulfuric Acid ◽  
Acid Attack ◽  
Sewer Pipes ◽  
Different Types

One-Year Sulfate Attack on Various Types of Fine Grained Concrete

2015 ◽  
Vol 1124 ◽  
pp. 313-318
Author(s):  
Martin Vyšvařil ◽  
Markéta Rovnaníková
Keyword(s):  
Sulfuric Acid ◽  
Acid Corrosion ◽  
Surrounding Medium ◽  
Mineralogical Composition ◽  
Sulfate Solution ◽  
Xrd Analysis ◽  
Sewage Water ◽  
Sulfate Attack ◽  
Fine Grained ◽  
Ph Decrease

Concrete shows extensive degradation when exposed to the external sulfate attack, characterized by ingress of sulfate ions from surrounding medium. This process leads to gradual pH decrease, to expansion, cracking, spalling of concrete, and finally to the complete disintegration of the material. Sulfate attack 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. 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, 5% sodium sulfate solution and solution simulating sewage water on various types of concrete has been investigated. The concrete specimens were characterized after exposition to corroding media by their mechanical parameters, microstructure and in the case of H2SO4 as the most aggressive corroding solution, the mineralogical composition was also determined by XRD analysis. It was found that the exposition to Na2SO4 solution twofold improved flexural strengths of concrete mixes based on Portland and sulfate-resisting cements. Contrary, the exposition to H2SO4 solution significantly decreased compressive strengths of all types of concrete.

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

2004 ◽  
Vol 34 (12) ◽  
pp. 2223-2236 ◽  
Author(s):  
N. De Belie ◽  
J. Monteny ◽  
A. Beeldens ◽  
E. Vincke ◽  
D. Van Gemert ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Experimental Research ◽  
Sewer Pipes ◽  
Different Types

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

Water ◽  
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.

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

2018 ◽  
Vol 105 ◽  
pp. 126-133 ◽  
Author(s):  
Anaïs Grandclerc ◽  
Patrick Dangla ◽  
Marielle Gueguen-Minerbe ◽  
Thierry Chaussadent
Keyword(s):  
Sulfuric Acid ◽  
Cementitious Materials ◽  
Acid Attack ◽  
Different Types

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

Materials ◽  
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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