It also provides improved durability for concrete in most aggressive environments, reducing. Sulphate attack on concrete is a chemical breakdown mechanism where sulphate ions attack components of the cement paste. Formulation of sulphate resistant super sulphated cement. Addition of an optimum amount of super plasticizer increases positive properties of the concrete with 15% osa addi tion, binds free caoh2 in opc, makes its. This difference leads to changes in the spectrum, which can be used for the specification of the sulfur compounds. Super sulphated cement is made from well granulated blast furnace slag 80 85%, calcium sulphate10 15%, and portland cement 1 2. The ratio of water cement at the time of use of super sulphated cement should not be less than 0. Cement is composed of mainly two minerals tricalcium silicates c3s and dicalcium silicates c2s. Effect of sulphate ions in mixing water on cement mortar. The mineral foams studied were mainly composed of a reactive, partially anhydrous calcium sulphate 90% and portland cement 10%, mixed with a low water to binder ratio wb 0.
Note field trial samples of fi nished cement with variable total so3 2. Present studies deal with the formulation of sulphate resistant super sulphated cement using flourogypsum 83 %, granulated blast furnace slag 10 % and opc 7% by grinding and blending in a. The experiments were carried out with two different slags, one with low reactivity lrslag and one with high reactivity hrslag. Sulphate resistant cement composition, properties, uses. The remedy of sulphate attack is sulphate resisting cement. Performances of cements were determined by means of compressive strength and. Mineralogical examination of the setting of super sulphated cement has shown that the rapid increase in strength up to a. Generally, the super sulphated cements ssc consist of 8085 wt. Developing a more rapid test to assess sulfate resistance. Chromate reduction in cement using ferrous sulfates. Where concrete is expected to be in contact with sulphates or other aggressive salts or solutions, analytical surveys must be completed and. The effect is studied with individual and double combination of the sulphates. Silica fume sulphate resistant concrete ideal alternative to low c 3 a cement introduction research2,6 over the last 1015 years has shown several technical problems with the use of low c3a cements srpc or type v cement. Setting time of cement concrete stages and processes.
The compounds responsible for sulphate attack on concrete are watersoluble sulphatecontaining salts, such as alkaliearth calcium, magnesium and alkali sodium, potassium sulphates that are capable of chemically reacting. Based on lerchs approach, optimum total so3 is in the range 2. Accelerated test for measuring sulfate resistance of. 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 nondistilled water. Properties of supersulphated phosphogysumslag cement ssc. The sulphate resistance of portland and blast furnace slag. Benefitsrecommended for use in belowground workreduced risk of alkali silica reaction declared crvi shelf life shown on bagpallet quantity25kg bag. Reduces damage to concrete, mortar and grout exposed to sulfate attack. This is manufactured to comply with astm c 15007 type ii and bs en 1971.
Effect of alkali source on expansion behavior for cement e 85. Pdf studied super sulfated cements ssc are composed with. In the literature this is referred as chemical attack 2. Sulphate resistant cement fauji cement company limited. C4af and swelling, spalling and cracking of concrete and causes c3sc2s ratio on sulphate attack. Given correct storage, the reducing effect of the ferrous sulfate in the cement is preserved over a period of more than six. Present studies deal with the formulation of sulphate resistant super sulphated cement using flourogypsum 83 %, granulated blast furnace slag 10 % and. Hydration mechanisms of super sulphated slag cement. In ppc cement that would act as a form of alkali activation of the pozzolanic reaction of the fly ash. Effect of sulfate content on cement mixtures sciencedirect. The strength properties of supersulfated cement are similar to those of portland cement, but it has. Ssc shows an increased resistance to sulphate attack and exhibits a lower heat of hydration compared to ordinary. Sulphate attack on concrete process and control of. Use of corrosion inhibiting admixtures and corrosion resistant steel, including epoxy coated and galvanized steel, allow for a higher chloride threshold concentration to be tolerated before the initiation of corrosion.
Other articles where supersulfated cement is discussed. Reduces the thermallyinduced stresses in large concrete pours. Hanson sulfateresisting cement technical data sheet. Supersulphated phosphogysumslag cement ssc is a newly developed nonburned cementitious material mainly composed of phosphogysum pg and ground granulated blast furnace slag ggbfs, with small amount of steel slag ss and clinker cl. Sulphate resisting cement is a cement with low c3a content and comparatively lower c4af content. The ideal cement solution for use in concrete, mortar and grout where sulfates are present. The only reason to add sodium sulphate is if the clinker is low. They must be fast setting and develop early strength as well as shrinkage compensation. Early and late hydration of supersulphated cements of blast furnace. Moderate sulfateresisting portland cement portland cement low alkali. Super sulphated cement ssc is one such binder which is sulphate resistant cement and produced by intergrinding a mixture of gbfs and calcium sulphate with a small quantity of portland cement. Sodium sulphate effect on cement produced with building. The cements sulphate resistance is due to its low tricalcium aluminate c3a content characteristics. Astm types of cement characteristics and properties of.
Sodium sulphate can be added in ppc cement production. Cements produced in a field trial, tested by isothermal calorimetry. Sem micrograph on a polished section for cement e, case arar 83 figure 36. The cement was introduced in 30 s to the water while mixing at about 419 rads 4000 rpm. Sulphate resisting cement is a type of portland cement having low tricalcium aluminate c3a content. Super sulphated cement ssc is one such binder which is sulphate resistant cement and produced by intergrinding a mixture of gbfs and. Lowering the watersoluble chromium content of cement to cement content leads to a super sulfated cement with a strength class 32. Evaluation of sulfate resistance of portland cement. Moderate and highsulphateresistant cements are used in situations where concrete is exposed to soils high in.
It complies with the requirements of bs 40271996, class 42. Effect of alkalis and sulfates on portland cement systems. Formulation of sulphate resistant super sulphated cement using. Sulfate resisting cement is designed to improve the performance of concrete where the risk of sulfate attack may be present. Otherwise the formation of calcium sulphoaluminate and gypsum would cause disruption of conrete due to an increase in volume of resultant compounds. The cement used meets the specifi cation for astm type i portland cement, bsa 370400 m2kg. In comparison with a significant reduction in the crosssectional area of the sodium sulphate attack, magnesium sulphate attack on. Introduction properties advantages disadvantages conclusion 3. Founded in 1904 and headquartered in farmington hills, michigan, usa, the american concrete institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensusbased standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete. The comparison of the results obtained for a same ssc binder formulation shows that the calcium sulfate. The slag with the low reactivity lrslag has a lower cao and al 2 o 3, but a higher sio 2 and mgo content compared to the hrslag. This process adversely affects concrete exposed to these damaging stimuli.
Sulfide s2 and sulfate so42, calculated as so3 in cement. Influences of the type and amount of calcium sulphate on. Sulphateresistant cement is recommended for use in concrete exposed to large sulphate levels. The main hydration products are ettringite and csh. In this study, the blended cements produced by using the building stone waste were exposed to sulphate solution and the cement properties were examined. Sulphur in the slag is originally present mainly as sulphide sii. Present studies deal with the formulation of sulphate resistant super sulphated cement using flourogypsum 83 %, granulated blast furnace slag 10 % and opc 7% by grinding and blending in a ball mill. The use of hanson sulfate resisting cement improves. A low alkali cement with a high sulfate resistance and a moderate heat of hydration. 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. Sulphate resistant cement sr type v sulphateresisting cement is more resistant than ordinary portland cement to the action of mineralized water containing sulphates.
Pdf formulation of sulphate resistant super sulphated. Upon hydration, the main reaction products are a calcium silicate gels csh and calcium hydroxide caoh2 or ch in cement chemistry. Sulfate resisting cement is recommended for use in all concrete, mortar and grout below ground or where sulfates are present in concentrations likely to. Pdf formulation of sulphate resistant super sulphated cement.
Effect of magnesium and sulphate ions on the sulphate. Hydration mechanisms of super sulphated slag cementj. Formulation of sulphate resistant super sulphated cement using fluorogypsum and granulated blast furnace slag. Where a considerable degree of attack is expected a sulphateresisting cement should be used, with a maximum watercement ratio of 0. British standard bs 40271980 specification for sulphate. Product data s heet sulfate resisting cement status. Bs 40271980 specification tiger cement is the leading exporter and supplier of british standard bs 40271980 sulphate resistant cement from pakistan. This cement has a low c3a content so as to avoid sulphate attack from outside the concrete. Optimization of cement sulfate part i cement without admixture introduction in 1946 william lerch published a paper on the optimum sulfate content in portland cement, which demonstrated that the optimum sulfate content with respect to mortar strength correlated closely with heat of hydration measured by isothermal calorimetry, and also with the.
If a sulphateresisting cement is used, the minimum cement content may be lower, e. The micro structure of hydrated super sulphated cement pdf free. The effect of sulphate ions on cement mortar concrete has been investigated by many authors. The aim would be to increase the early hydraulic reactivity of the cement. Ranjani et al, 2012 for example while studying on the behaviour of foam concrete under sulphate environments observed that sulphate ions resulted to expansion of concrete. Effect of sulfates on cement and limestabilized soils. Sulfateresisting bagged cement hanson packed products.
Xray diffraction xrd analysis shows that the hrslag. Initial setting time is defined as the period elapsing between the time when water is added to the cement and the time at which the needle of 1 mm square section fails to pierce the test block to a depth of about 5 mm from the bottom of the mould. The percentage of c3a tricalcium aluminate is kept below 5 percent and it results in the increase in resisting power against sulphate attack sulphate resisting cement is used the following circumstances. Sulphate resisting cement is recommended for use in aggressive sulphaterich environments where increased resistance to salt attack is required. Addition of ferrous sulfate to cement and risk of chromium. Evaluation of sulfate resistance of portland cement mortars containing lowcarbon rice husk ash harish kizhakkumodom venkatanarayanan1 and prasada rao rangaraju, p. The determination of sulfur species sulfide world cement. In this study, a lowcarbon rice husk ash rha was used as a supplementary cementing material in cement mortars to evaluate. With the mixer maintaining the speed of 419 rads, the cement paste was mixed for another 30 s. Pdf present studies deal with the formulation of sulphate resistant super sulphated cement using flourogypsum 83 %, granulated blast.
This product is kitemarked by bsi and our licence number is km 35068. The sulphates used in the present investigation are sodium sulphate, calcium sulphate, magnesium sulphate, ammonium sulphate and ferrous sulphate. Effect of sodium sulfate addition on properties of cement. The microstructure of these systems has been reported as very complex. When concrete is exposed to highly alkaline soil or water having high sulphate content then this type is used. Sulfates can often be found underground and in marine environments.
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