scholarly journals Corrosion Inhibitory Effects of Mullite in Concrete Exposed to Sulfuric Acid Attack

2020 ◽  
Vol 1 (2) ◽  
pp. 282-295
Author(s):  
Shima Taheri ◽  
Gerardo Pareja Delgado ◽  
Oluwatoosin B. A. Agbaje ◽  
Paritosh Giri ◽  
Simon Martin Clark
Keyword(s):  
Sulfuric Acid ◽  
Prolonged Exposure ◽  
Acid Corrosion ◽  
Hardness Test ◽  
Aluminum Silicate ◽  
Acid Attack ◽  
Concrete Pipes ◽  
Physicochemical Changes ◽  
Sulfuric Acid Solutions

Prolonged exposure to low pH conditions affects the durability of concrete. In this work, the effect of mullite, aluminum silicate, on the strength and the acid corrosion of mortar and concrete under induced accelerated conditions in sulfuric acid solutions at pH of 0.25 and 1 was studied. The characterization of physicochemical changes was performed using techniques including compressive strength, scanning electron microscopy, micro-X-ray fluorescence spectrometry, and the Vickers hardness test. The results indicate that the addition of mullite does not have any significant effect on the overall strength of mortar and concrete samples, while it significantly increases their resistance to corrosion caused by sulfate attack by 90%, therefore, it is expected to increase the life span and decrease the maintenance costs of concrete pipes subjected to acid corrosion in sewer environments. The inhibition efficiency is observed to be sensitive to acid concentration and was improved with increase in the amount of mullite in samples.

scholarly journals An investigation of the chemical composition and acid corrosion of pedra sabão (soapstone)

2005 ◽  
Vol 70 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Farias de
Keyword(s):  
Sulfuric Acid ◽  
Chemical Composition ◽  
Acid Corrosion ◽  
Acid Solutions ◽  
Nmr Analysis ◽  
Acid Attack ◽  
Basic Study ◽  
Oh Groups ◽  
Composition And Structure ◽  
Sulfuric Acid Solutions

In this paper the results of a basic study of the chemical composition and structure of soapstone are reported. An investigation of the effects of aqueous sulfuric acid solutions on the physical integrity of the stone was also performed. The studied soapstone samples had a lamellar nanostructure as verified by DRX data. Furthermore, they contained isolated silanol (Si-OH) groups, as indicated by FTIR data, and the majority of the silicon atoms were bonded to OH groups, as shown by 29Si CPMAS NMR analysis. Is was also shown that a low resistance to acid attack is associated with a large amount of magnesium and/or iron in the stone.

Mineralogical and physico-chemical characteristics of Cameroonian smectitic clays after treatment with weakly sulfuric acid

Clay Minerals ◽  
2015 ◽  
Vol 50 (5) ◽  
pp. 649-661 ◽  
Author(s):  
J.R. Mache ◽  
P. Signing ◽  
J.A. Mbey ◽  
A. Razafitianamaharavo ◽  
D. Njopwouo ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Structural Modification ◽  
Morphological Characteristics ◽  
Textural Properties ◽  
Exchange Capacity ◽  
Acid Solutions ◽  
Acid Attack ◽  
Physico Chemical ◽  
Dioctahedral Smectite ◽  
Sulfuric Acid Solutions

AbstractSmectitic clays from the Sabga and Bana areas, western Cameroon were treated with sulfuric-acid solutions of various concentrations – 0.5, 0.7, 1.0 and 4.0 N – at 80°C for 2 h. The mineralogical, physicochemical and morphological characteristics of the samples treated were analysed using several techniques. The sulfuric acid caused structural modification of the dioctahedral smectite. The accessory minerals such as cristobalite, quartz, feldspars and anatase remained unaltered by the acid attack. The supernatant solutions after acid treatment contain Mg, Ca, K, Na, Si, Al and Fe as a result of partial dissolution of octahedral and tetrahedral cations. The activated clay samples exhibited a smaller cation exchange capacity (CEC) and the specific surface area (SSA) increased with increasing concentration of sulfuric acid, ranging from 65 to 134 m2/g for the sample from Bana and from 74 to 84 m2/g for the sample from Sabga. The different SSAvalues were affected by the relative abundance of smectite and cristobalite (SiO2/Al2O3 = 2.2 and 6.5, respectively, from Bana and Sabga). The activated clays from Bana and Sabga displayed interesting physicochemical and textural properties and can be considered as promising adsorbents for the bleaching of vegetable oils.

scholarly journals Characterization of sulfur oxidizing bacteria related to biogenic sulfuric acid corrosion in sludge digesters

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Bettina Huber ◽  
Bastian Herzog ◽  
Jörg E. Drewes ◽  
Konrad Koch ◽  
Elisabeth Müller
Keyword(s):  
Sulfuric Acid ◽  
Acid Corrosion ◽  
Sulfuric Acid Corrosion ◽  
Sulfur Oxidizing ◽  
Sulfur Oxidizing Bacteria

scholarly journals Sulfuric Acid Resistance of CNT-Cementitious Composites

2021 ◽  
Vol 11 (5) ◽  
pp. 2226
Author(s):  
Gun-Cheol Lee ◽  
Youngmin Kim ◽  
Soo-Yeon Seo ◽  
Hyun-Do Yun ◽  
Seongwon Hong
Keyword(s):  
Sulfuric Acid ◽  
Electrical Properties ◽  
Mechanical Performance ◽  
Cement Mortar ◽  
Acid Corrosion ◽  
Acid Resistance ◽  
Sulfate Attack ◽  
Cementitious Composites ◽  
Sulfuric Acid Solutions ◽  
Single Walled Cnts

This study analyzed changes in the durability characteristics of cement mortar incorporating carbon nanotube (CNT) and the electrical properties subjected to deterioration induced by sulfate attack. Powder types of multi-walled or single-walled CNTs were used and added to the composites with 1.0% and 2.0% mass fraction, and the specimens were immersed in 5% and 10% sulfuric acid solutions to investigate the durability of CNT cementitious composites. Although mechanical performance decreased due to relatively large pores (370–80 μm) caused by CNTs, specimens incorporating CNTs exhibited enhanced resistance to sulfuric acid as CNTs, which offered strong resistance to acid corrosion, and prevented contact between the cement hydrate and the sulfuric acid solution. Therefore, it is expected that self-sensing performance was exhibited because there were no significant differences in the electrical properties of cement mortar subjected to the deterioration by sulfate attack.

scholarly journals The effect of pozzolanic mineral additives on the strength and durability properties of structural lightweight concrete

2021 ◽  
Vol 2 (2) ◽  
pp. 35-40
Author(s):  
Engin Yener
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Lightweight Concrete ◽  
Acid Resistance ◽  
High Strength ◽  
Strength Development ◽  
Acid Attack ◽  
Ductile Behavior ◽  
Sulfuric Acid Solutions

Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

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.

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