4.1 The amount of acid-soluble chloride in most hydraulic-cement systems is equal to the total amount of chloride in the system. However, some organic substances that may be introduced into mortar or concrete contain chloride that is initially acid-insoluble that can eventually ionize and thus become acid-soluble or water-soluble after a period of exposure in the very alkaline cement system.
Read More
The test for acid-soluble chlorides (ASTM C 1152) treats crushed material with nitric acid rather than water. Almost all of the chlorides present in the concrete are detected, whether they are bound or are available to cause corro-sion. Because the test method finds all chlorides, limits based upon acid-soluble chloride content are higher than
Read More
The presence of sulfate ions and low pH represent the most aggressive conditions for concrete structures. Studies on the performance of concrete in acid solutions (H 2 SO 4, HNO 3, HCl) from industrial waters have shown a large and fast concrete deterioration, due to the transport of soluble
Read More
(a) Use of Sulphate Resistant Cement: To control or resist the sulphate effect on concrete the most effective and efficient method is the use of low calcium aluminate (C 3 A) cement. In general it can be said that 7% C 3 A content is a rough division between cement of good and poor performance in sulphate waters. (b) Quality of Concrete: A well designed, prepared dense and impermeable concrete ...
Read More
Self-compacting concrete requires high powder content which implies increased cost and increased CO 2 emission into the environment; hence, the need for the inculcation of a supplementary cementitious material (SCM) to the concrete mix such as corn cob ash (CCA) which is obtained by drying, grinding and burning the corn cobs. The chemical composition of the corn cob ash showed that it was ...
Read More
The primary effect of any type of acid attack on concrete is the dissolution of the cement paste matrix. This weakens the affected concrete, but unlike sulfate attack, the degradation does not involve significant expansion. Neither ettringite nor thaumasite are stable in acid solution so that the reaction product from sulfuric acid
Read More
(fil. Since effects of frost action on concrete are not within the scope of this sym posium, thi::; subject is 11ul developed fw•thcr b re. The secolld important effect on concrete related to wetting and drying is the volume change relations due to changes in, or changes in uniformity of, moisture content.
Read More
Table 1 Some of common acids, solubility of calcium salts, chemical formula and their likely occurrence. Chemical substance Formula Likely occurrence Sulfuric acid (Solubility of calcium sulfate in water: 0.20%) H2SO4 Natural ground waters [13, 14], chemical industry [13], effluents from furnaces (that use
Read More
Concrete degradation may have various causes.Concrete can be damaged by fire, aggregate expansion, sea water effects, bacterial corrosion, calcium leaching, physical damage and chemical damage (from carbonatation, chlorides, sulfates and non-distilled water).This process adversely affects concrete exposed to these damaging stimuli.
Read More
Acid sulfate soil conditions and associated sulfuricization reactions generate a number of extreme soil and water quality challenges. First of all, plants are killed by direct effects of low pH, high heavy metal solubility and soluble sulfate salt stress. The extrem ely acid (pH 1.8 to 3.8) soil solutions and percolates directly degrade ...
Read More
The acid-soluble chloride ion level at which steel reinforcement corrosion begins in concrete is about 0.2% to 0.4% by mass of cement. Placing an acceptable limit on chloride content for any one ingredient, such as mixing water, is problematic considering the variety of sources of chloride ions in concrete.
Read More
The total (acid-soluble) chloride ion level at which steel reinforcement corrosion begins in concrete is about 0.2% to 0.4% by mass of cement. The ACI 318 building code and CSA Standard A23.1 limit water soluble chloride ion content in reinforced concrete to the following percentages by mass of cement.
Read More
reduced concentration of sulphate added to the treated water. This directly affects SO4 levels in domestic wastewater. A raw water with a sulphate level of 3 to 5 mg/L will typically have a SO4 concentration of 15 to 25 mg/L following treatment with alum. The amount of soluble sulphate present in …
Read More
Jul 01, 2000· Title: Effect of Sodium Sulfate Addition on Properties of Cement Pastes Containing Different Molecular Weight PNS Superplasticizers Author(s): B.-G. Kim, S. Jiang, and P.-C. Aiitcin Publication: Symposium Paper Volume: 195 Issue: Appears on pages(s): 485-504 Keywords: adsorption; alkali; cement; superplasticizer Date: 7/1/2000 Abstract: The effects of Na2S04 addition to cement …
Read More
Jul 17, 2016· Sulphate attack might show itself in different forms depending upon the chemical form of the sulfate and the atmospheric environment which the concrete is exposed to. Groundwater or soil contains soluble sulfates naturally or sometimes it comes from the industrial effluents or fertilizers which sometimes also contains amounium sulfate which ...
Read More
Sep 29, 2014· So use sulphate resisting cement which contains less C3A. Quality Concrete : A well designed, placed and compacted concrete exhibit higher resistance to sulphate attack. Use of air-entrainment: Use of air-entrainment to the extend of about 6% has beneficial effect on sulphate …
Read More
Acid sulfate soils explained. Common in many parts of the world, acid sulfate soils are saturated with water, almost oxygen-free and contain microscopic crystals of iron sulfide minerals (commonly pyrite ). Acid sulfate soils are safe and harmless when not disturbed. If acid sulfate soils are dug up or drained they come into contact with oxygen.
Read More
8 Sulfate damage to concrete floors on sulfate-bearing hardcore To produce deleterious amounts of ettringite the reaction requires the presence of: • a significantconcentration of water-soluble sulfates • concrete which contains a substantial content of calcium aluminate hydrates, as is the case in concrete made with most Portland cements
Read More
Big Effect was W/C Increasing W/C Concrete with Type II Moderate Sulfate Resisting Cement after 5 years exposure on-grade in sulfate soil in California (Chemical + Physical Attack) Without entrained air With entrained air PCA Old PCA Sacramento Site D. Stark 1982 (PCA RD086) Effect of Class F Fly Ash on Type II Cement 0.38 0.48 0.68 Avg. w/cm
Read More
May 07, 2015· In this study, the blended cements produced by using the building stone waste were exposed to sulphate solution and the cement properties were examined. Prepared mortar specimens were cured under water for 28 days and then they were exposed to three different proportions of sodium sulphate solution for 125 days. Performances of cements were determined by means of compressive …
Read More
The sulphate concentration in sea water (in soluble, available form) is extremely high and is of the order of concentration that has proved to be damaging to concrete in groundwater. The fact that much concrete in sea water is only partly immersed and therefore subject to high moisture intake is certain to pose a sulphate threat.
Read More
Compared to the acid-soluble test, this method is less reliable because of the effect that factors such as extraction time, temperature, sample size, and concrete age have on the results obtained. Of the two, the acid-soluble test method is more commonly used because of …
Read More
found that the course of action of acid attack is dependent on the type of acid and solubility of the calcium salt formed. The presence of mineral admixtures was found to lower the detrimental effect of all types of acids on concrete. Ternary ... sulfate ions tend to initiate sulfate attack (Hewayde et al.
Read More
Sulfate attack is another possible deterioration mechanism of concrete. It can have endogenous origin (developing without any contribution from the environment) or exogenous origins (such as sulfates contained in the soils or in liquids) (Germain, 2008; Neville, 2004).In both cases, the consequence is some volume expansion owing to the delayed formation of ettringite, which is an expansive ...
Read More
Jul 17, 2016· Sulphate attack might show itself in different forms depending upon the chemical form of the sulfate and the atmospheric environment which the concrete is exposed to. Groundwater or soil contains soluble sulfates naturally or sometimes it comes from the industrial effluents or fertilizers which sometimes also contains amounium sulfate …
Read More
May 07, 2015· Determination of Soluble Sulphate Content Purpose Sodium sulphate is present in some soils. The salt is easily hydrated and dehydrated under the influence of climatic changes. There are enormous volume changes during this process of hydration and dehydration, which influence the engineering properties of soils. Procedure Take the soil sample in a state in which […]
Read More
The main reason for the increased acid resistance of the concrete investigated was the formation of a very dense hardened cement paste and aggregate interface with very low porosities. The use of slag cement increased acid resistance as well as portland cements with silica fume (up to 8 percent by mass of cementitious material) or fly ash.
Read More
Jan 14, 2017· Clause 6.2.5.3 of BS 8110 Part-1: 1995, Structural use of concrete had a limit of 4% by mass of cement based on the total acid soluble content of the concrete mix, expressed as SO3. This ...
Read More
Jan 28, 2013· The effect of the addition of organic solvents, such as ethyl acetate (EA), glycerol (GLY), isopropyl alcohol (IPA), dimethylformamide (DMF), oxalic acid (OA), and propylamine (PA), on the solubility behavior of calcium sulfate dihydrate (gypsum, CaSO 4 ·2H 2 O) in aqueous NaCl solutions has been examined at 35 °C. Compared to organic solvent free system, the addition of EA slightly ...
Read More
Effect of Chloride and Sulfate Contamination in Soils on ... danger of deterioration and disintegration of concrete due to the reaction between sulfate salts and the compounds of ce ... and titrating the filtrate against 0.01 M sulfuric acid. Corrosion Monitoring
Read More
Sulfate in concrete Excessive amounts of mobile sulfate, derived from aggregates or other constituents in concrete, can cause disruption due to expansion. BS 8110 part 1 Structural use of concrete, 1985, had a limit of 4% by mass of cement based on the total acid soluble sulfate method expressed as SO 3 (clauses 6.2.5.3).
Read More
Sulphate – The cement & other aggregates contain some limited volume of sulphate content. If it exceeds the limitation it may lead to cracks on concrete. To avoid this, the sulphate content in concrete should not be exceeded by 4% by the mass of cement in concrete.
Read More
Scope. 1.1 This test method is for the determination of water-soluble sulfate in soils. 1.2 This test method was developed for concentrations of water-soluble sulfate in soils between 0.02 and 3.33 % sulfate by mass. 1.3 This test method does not determine sulfur in any form except as sulfate. 1.4 Some governing bodies regulate the movement of ...
Read More
(a) Use of Sulphate Resistant Cement: To control or resist the sulphate effect on concrete the most effective and efficient method is the use of low calcium aluminate (C 3 A) cement. In general it can be said that 7% C 3 A content is a rough division between cement of good and poor performance in sulphate waters. (b) Quality of Concrete: A well designed, prepared dense and impermeable concrete ...
Read More
Thus, in acid sulfate soils, the aggressiveness of the environment needs to be assessed separately for the effects of sulfate and acid. Tables 2 & 3 set out recommen-dations applicable to pipe manufactured in accordance with AS/NZS 4058 resulting in w/c ratio < 0.4 and water absorption < 6%. Table 2
Read More
The combined effect of sulphates present in aggregates and high levels of chloride ions in the mixing water on some properties of concrete was studied. Different amounts of sulphates in sand (0.38, 0.50, 0.75 and 1.0% SO3) with chloride contents in water (50, 750, 1000, 3000 and 6000 p.p.m. as Cl−) were used. The compressive strength was lower for concrete with higher sulphate contents at ...
Read More
resistance to acid attack for mortar mixes were not significant compared to concrete mixes. The loss in weight of concrete when immersed in sulphuric acid is mainly due to the action of sulphuric acid on concrete. SuIphuric acid attacks the calcium hydroxide in concrete and convert it to calcium sulphate which can be leached out of concrete.
Read More
Through 30 year's hard work, mex's staff built supremacy of credibility, excellent quality.
