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Micro Silica Micro Silica is designed to give a big Qualitative boost to Concrete. It is well recognizedthat Concrete Mix for High Strength cannot be achieved without some extra cementitiousmaterialbeyond Cement& Fly ash. HereMicro Silicaplays avital rolein   ü  IncreasingCompressive, Flexural andbondstrengthsinconcrete. ü  ImprovestheLifeofConcreteby actingasCorrosionInhibitorforReinforcement. ü  Improves the Life of Concrete by reducing Alkali-Silica Reaction (ASR)orConcrete Cancer. Micro Silica is a mineral admixture comprising of very fine solid glassy spheres of silicondioxide (SiO2). Micro Silica is fine amorphous silica with particle size around 100 timessmaller than averageparticlesizeofcement andflyash.     HigherCompressive, Flexural&BondStrengthwithMicro Silica ü  The silica present in Micro Silica, reacts with the weaker calcium hydroxide releasedduring the hydration of cement and forms additional calcium silicate hydrate (C – S –H). The concrete derives greater strength from higher concentration of strong CalciumSilicateHydrate replacingweak andeasily solublecalciumhydroxide.   ü  Micro Silica is like a pozzolanic material which provides more uniform distributionandagreatervolumeofhydrationinconcretestructures.ThischangestheRheologyofconcreteandreducesthewater-binderratio.Thisinturnresultsintohighercompressivestrength. ReinforcementCorrosionInhibitorroleofMicro Silica ü  With particle size of 1/100thof cement & fly ash, Micro Silica drastically reducestheaveragesizeofporesintheconcrete.Thisdrasticallyreduceswaterpermeabilityinconcrete.   ü  Lower water-binder ratio achieved by adding Micro Silica ensure that the concretedoesnot loose waterduring setting and nopin holes are created.   ü  It reduces the rate of carbonation, decreases permeability to chloride ions and impartshighelectricalresistivity.Henceitprotectsthereinforcement steeland embedment.   ü  As an additional functional benefit, this reduces the instances of damp and waterleakagetroubles.     ResistanttoConcreteCancer(Alkali-AggregateReaction)   ü  CementHydrationprocessproducesCalciumHydroxidealongwithSodiumandPotassiumoxides which has the followingimpacton concreteat a laterstage: §  With age the porosity of concrete gathers sufficient moisture to aid a swellingreaction between highly alkaline cement paste and the reactive non-crystallinesilica found in many aggregates. This form hydroscopic gel of Sodium Silicatewhich swells absorbing further moisture weakening the concrete and creatingcracks. These cracks lead to increased porosity which in turn exponentiallypropagates the process of disintegration. That is the reason it is termed asConcreteCancer.   §  IncaseofSulfateattack, freecalciumhydroxidereactstoproducecalciumsulphate.This brings acidity inconcrete andweakens thestructure. ü  Micro Silica acts with the policy of “fight Fire with Fire” to combat ASR reaction. Itinitiates a prompt reaction at early stage of concrete hardening. Thus, it binds thesetroublemakers, i.e.Calcium Hydroxide along with Sodium and Potassium oxides. Thus, they are arrested and quarantined notallowingthemtocreatemuchtroubleatlaterstage.AddtothisthefactthatMicro Silica has already reduced the porosity and hence curtailing the availability ofmoisture, theotherkey requirement for this process.     Recommendation   Micro Silica can be mixed between 5-10% of cement used in Concrete Mix for excellentperformance.

Metakaolin is a pozzolan, probably the most effective pozzolanic material for use in concrete. It is a product that is manufactured for use rather than a by-product and is formed when china clay, the mineral kaolin, is heated to a temperature between 600 and 800ºC. Its quality is controlled during manufacture, resulting in a much less variable material than industrial pozzolans that are by-products. First used in the 1960s for the construction of a number of large dams in Brazil, metakaolin was successfully incorporated into the concrete with the original intention of suppressing any damage due to alkali-silica reaction. When used to replace cement at levels of 5 to 10% by weight, the concrete produced is generally more cohesive and less likely to bleed. As a result pumping and finishing processes require less effort. The compressive strength of hardened concrete is also increased at this level of replacement. Slightly higher replacement levels (up to 20%) produce a cement matrix that has low porosity and permeability. This results in improvements to resistance of the hardened concrete to attack by sulfates, chloride ions and other aggressive substances, such as mineral and organic acids. Freeze/ thaw resistance is improved and the risk of damage resulting from the effects of impact or abrasion is reduced for metakaolin concrete that has been finished and cured properly.

Microsilica can be used in concrete and refractory materials. Microsilica , when used in concrete, it can improve concretes properties such as compressive strength, bond strength and abrasion resistance, reduces permeability, and therefore helps in protecting reinforcing steel from corrosion. Micro SilicaMicro Silica is designed to give a big Qualitative boost to Concrete. It is well recognized that Concrete Mix for High Strength cannot be achieved without some extra cementitious material beyond Cement & Fly ash.Here Micro Silica plays a vital role in Increasing Compressive, Flexural and bond strengths in concrete.Improves the Life of Concrete by acting as Corrosion Inhibitor for Reinforcement.Improves the Life of Concrete by reducing Alkali-Silica Reaction (ASR) or Concrete Cancer.Micro Silica is a mineral admixture comprising of very fine solid glassy spheres of silicon dioxide (SiO2). MicroSilica is fine amorphous silica with particle size around 100 times smaller than average particle size of cement and fly ash. Higher Compressive, Flexural & Bond Strength with Micro SilicaThe silica present in Micro Silica, reacts with the weaker calcium hydroxide released during the hydration of cement and forms additional calcium silicate hydrate (C S H). The concrete derives greater strength from higher concentration of strong Calcium Silicate Hydrate replacing weak and easily soluble calcium hydroxide. Micro Silica is like a pozzolanic material which provides more uniform distribution and a greater volume of hydration in concrete structures. This changes the Rheology of concrete and reduces the water-binder ratio. This in turn results into higher compressive strength. Reinforcement Corrosion Inhibitor role of Micro SilicaWith particle size of 1/100th of cement & fly ash, Micro Silica drastically reduces the average size of pores in the concrete. This drastically reduces water permeability in concrete. Lower water-binder ratio achieved by adding Micro Silica ensure that the concrete does not loose water during setting and no pin holes are created. It reduces the rate of carbonation, decreases permeability to chloride ions and imparts high electrical resistivity. Hence it protects the reinforcement steel and embedment. As an additional functional benefit, this reduces the instances of damp and water leakage troubles. Resistant to Concrete Cancer (Alkali-Aggregate Reaction) Cement Hydration process produces Calcium Hydroxide along with Sodium and Potassium oxides which has the following impact on concrete at a later stage:With age the porosity of concrete gathers sufficient moisture to aid a swelling reaction between highly alkaline cement paste and the reactive non-crystalline silica found in many aggregates. This form hydroscopic gel of Sodium Silicate which swells absorbing further moisture weakening the concrete and creating cracks. These cracks lead to increased porosity which in turn exponentially propagates the process of disintegration. That is the reason it is termed as Concrete Cancer. In case of Sulfate attack, free calcium hydroxide reacts to produce calcium sulphate. This brings acidity in concrete and weakens the structure.Micro Silica acts with the policy of fight Fire with Fire to combat ASR reaction. It initiates a prompt reaction at early stage of concrete hardening. Thus, it binds these trouble makers, i.e. Calcium Hydroxidealong with Sodium and Potassium oxides. Thus, they are arrested and quarantined not allowing them to create much trouble at later stage. Add to this the fact that Micro Silica has already reduced the porosity and hence curtailing the availability of moisture, the other key requirement for this process. RecommendationMicro Silica can be mixed between 5-10% of cement used in Concrete Mix for excellentperformance.

The Pozzocrete Fly Ash range is an artificial pozzolan, specially designed to achieve optimum performance on most cement and concrete applications. In the production of Pozzocrete 40™, 60™, 63™, and 83™ high quality PFA were selected and industrially processed in order to obtain maximum performance as a cement replacement product.The POZZOCRETE brand is reserved only for those grades which meet the Indian Standard 3812 , the European Standard EN450 Category S and the American Standard ASTM 618. Other by-products are called P. (with the related Grade number). The process used to produce Pozzocrete Fly Ash significantly reduces the amount of unburned particles leading to a virtually carbon free material. Optimum reactivity is obtained by rejecting the less reactive crystalline Fly Ash particles and by increasing the specific surface of the final product. POZZOCRETE products are available, depending on the product grade, in 30 kg paper bags, 50 kg HDP bags, Jumbo (big) bags carrying 1 – 1.3 ts , loose supply in 15 – 25 ts road tankers (bulkers)  and on customer request in break bulk shipments. The P-grades (with the exception of the P10 grade) are only available in big-bags or in bulker. The design of all Pozzocrete grades has taken into account the severe weather conditions in the areas where it may be supplied, in order to allow high cement replacement volumes insuring adequate strength development and good durability whilst avoiding short-term damage such as bleeding and thermo-hygrometric plastic shrinkage

Metakaolin grades of calcined clays are reactive allumino silicate pozzolan formed by calcining very pure hydrous chinaclay. Chamically metakaoline combines with calcium hydroxide to form calcium silicate and calcium alluminate hydrates. Unlike other natural pozzolan metakaolin is water processed to remove unreactive impurities producing an almost 100 percent reactive material.the particle size of metakaolin is significantly smaller than cement particles. Is 456:2000 recommends use of metakaolin as mineral admixture.Metakaolin is a pozzolan, probably the most effective pozzolanic material for use in concrete. It is a product that is manufactured for use rather than a by-product and is formed when china clay, the mineral kaolin, is heated to a temperature between 600 and 800C. Its quality is controlled during manufacture, resulting in a much less variable material than industrial pozzolans that are by-products. First used in the 1960s for the construction of a number of large dams in Brazil, metakaolin was successfully incorporated into the concrete with the original intention of suppressing any damage due to alkali-silica reaction. When used to replace cement at levels of 5 to 10% by weight, the concrete produced is generally more cohesive and less likely to bleed. As a result pumping and finishing processes require less effort. The compressive strength of hardened concrete is also increased at this level of replacement.Slightly higher replacement levels (up to 20%) produce a cement matrix that has low porosity and permeability. This results in improvements to resistance of the hardened concrete to attack by sulfates, chloride ions and other aggressive substances, such as mineral and organic acids. Freeze/ thaw resistance is improved and the risk of damage resulting from the effects of impact or abrasion is reduced for metakaolin concrete that has been finished and cured properly.