During the extraction of liquid raw iron by reducing the iron ore in the furnace, “high furnace slag” is formed when the slag-forming elements are oxidized and collected on hot mine. • Iron ore, limestone and Coke are used as raw materials in iron production. Iron ore contains non-ferrous materials such as silica, sulfur and alumina together with iron oxide. As a result of the process in the high furnace, these materials are decomposed. Limestone serves as an auxiliary raw material in this process. Coke coal provides the necessary fuel.The temperature reaches 1600 C in high furnaces fed continuously with raw materials. As a result of high temperature melting materials are collected in the lower part of the furnace with slag on top and peak iron on bottom. Molten slag and iron are discharged separately. After discharge of the high furnace slag at 1500 C, the cooling method to be applied determines the characteristics and usage of the product.
Cooling Of BlastFurnace • SlagAir Cooling: the YFC is slowly cooled in atmospheric conditions by the air cooling method and consists of a mineralogy of large crystal material. This material with low glass phase can be used as concrete or asphalt aggregate or stabilization material by breaking. • Expansion: if YFC is cooled with controlled amount of water, pressurized air and steam, a large crystal grain material is formed in porous structure. This material can be used in lightweight concrete production due to its lightness. • Granulation: as a result of the sudden cooling process using more water than the expansion, a granulated material with hydraulic properties is formed in a similar amorphous structure to the sand. This material is grinded in the mill and “grinded granule high furnace slag” is obtained. Although the method of using 10 tons of water to obtain 1 tons granulated YFC is the most efficient way, it is not economical
EFFECTS OF BLAST FURNACE SLAG ON CONCRETE • Effect Of Fresh Concrete Properties • Hydration heat: one of the most important and effective benefits of high Furnace Slag Cement is the reduction of hydration heat. As is known, hydration heat causes thermal stresses in mass concrete. Especially in hot weather conditions, the difference in internal and external temperature in large section of concrete causes thermal cracks without compensation. For this reason, it is ideal for high Furnace Slag Cement to be used in mass concrete.
Setting time: high Furnace Slag Cement with low hydration temperature, the reaction of the components in cement due to the slower development of the setting time is prolonged. In periods where the air temperature is high, the concrete is getting a fast socket creates problems in practice. For this reason, the use of high Furnace Slag Cement is very useful in hot weather. In winter months, because the air temperature is low, the setting time naturally prolongs. However, this situation is prevented with proper slag content and plug accelerator additives.
Bfseffect of fresh concrete • Workability: Although the grains of blast furnace slag are angular, they are glassy, smooth and less absorbent. In addition, it has a lower specific gravity than PortlandCement and thus provides more cement in the same dosage. For these reasons, workability in concrete is affected positively.
Permeability: The hydration reaction resulting from the reaction of Blast FurnaceSlag Cement with water takes place in two stages. C-S-H jelly formation, which has the strength to give strength, takes place in a high amount. Ca(OH)2 and etrengit amount is lower. This results in a denser, smaller and less hollow structure. This situation develops as the amount of slag increases.
Effect Of Slag Cement On Concrete Durability • Alkali-silica reaction (ASR):ASR result, the gels formed in concrete are in a structure that expands volumatically if there is sufficient amount of water present. As a result of expansion, serious damage occurs in concrete. ASR reaction is a slow progressive and short-term non-observable reaction. Because the amount of clinker is low in the high furnace slag cement, the total amount of alkali is also low and ASR risk is reduced as a result.
METAKAOLİN DEFİNATİON-ORİGİN-TYPES ÖMER FARUK GÜLER
What is metakaolin? • It is a mineral additive used in the production of high performance cement based materials. • The main feature that distinguishes metakaolin from other mineral additivesproduction is different. • Other mineral admixtures are either obtained by natural means orindustry waste.
Production of metakaolin • Metakaolin is obtained by keeping the pure clay at a temperature of about 700 ° C for 30-60 minutes and by completely evaporating the bound water.
Main features • Contains high amounts of amorphous silica. • It is whitecolor. • Prevents durability problems such as alkali-silica reaction, sulfate attack and flowering. • Adds impermeability to concrete elements.
Basic Features of Metakaolin • 50-55% SiO2% 45-50% Al2O3 consists of. • Surface area is 1500-2500 cm2 / g similar to cement. • Density is approximately 2.5 g / cm3. • Average Particle Size is below 2 Microns.
Basic Uses of Metakaolin • TileProduction • Glass Fiber ReinforcedConcrete • ColoredConcrete Applications • Paving Stones.
Effect on Alkali-SilicaReaction when metakaolin is used as partial replacement for cement, its effect is to dilute the cement, which reduces the alkali content of the concrete system and the pH of the pore solution, thereby increasing the solubility of calcium and promoting the formation of non-expanding gel.
Effect on Sulphate Attack • MK replacement affects is resistance to sulfate attack. The sulfate attack is generally attributed to the reaction of sulfate ions with calcium hydroxide and calcium aluminate hydrate to form gypsum and ettringite. The gypsum and ettringite formed as a result of sulfate attack is significantly more voluminous (1.2–2.2 times) than the initial reactants
SET ACCELERATORS Hakan TURAN
Definiton • Acceleratingadmixtures can be usedeithertoincreasethe rate of stiffening/settingof theconcreteortoincreasethe rate of hardeningandearlystrengthgaintoallowearlierdemouldingandhandling.
Aim • Accelerators aremosteffective at lowtemperature. Prime use of set accelerators is in thecontrol of thesetting time of concrete. • Accelerators arealsousedtoreducethe risk of damagebyfreezingwhenconcreting in coldweatherandtoallowtheearlierremoval of formwork. Theexposedfaces of struckconcretemuststill be protectedandproperlycured. • Some have accelerating and water-reducing properties (ASTM C494 Type E chemical admixtures), while some are only accelerators (ASTM C494 Type C chemical admixtures).
Aim • Otherapplicationswhereacceleratingadmixturesareusedare in urgentconcreterepairsand in seadefencework, toensureearlystiffening of concrete in thetidalzone. • Veryfast set acceleratingadmixturesareusedforsprayedconcrete (shotcrete)
How It Works? • Set accelerators work by acting as a catalyst for hydration reactions. • Acceleratingadmixturesincreasethe rate of hydration of tricalciumsilicate (C3S) andtricalciumaluminate (C3A) phases of thecement, therebyprovidingearlierheatevolutionandstrengthdevelopment. • Theacceleratingeffect of both set andstrengthacceleratingadmixtures is mostpronounced at lowertemperatures of theorderto 5-10oC.
Calcium Chloride in Portland Cement Concrete InitialSetting Time: The time towhichcement can be mouldedintoanydesiredshapewithoutlosingitsstrenght is calledInitialSetting Time of cement. FinalSetting Time: The time at whichcementcompletelylosesitsplasticityandbecame hard is a Final Setting Time of cement.
POLYMER CONCRETE Veysel Fadli KIZIL 44563000664
What is thepolymerconcrete? • Concretes are polymer with binder. Monomer and aggregate mixture is obtained by polymerization • Polymer concrete - as well as a special building material used as a binder for the replacement of lime cements. • It is a versatile durable composite material obtained by blending various mineral fillers with synthetic or natural astringent materials.
Thecontents of • It is a type of concrete made of portland cement material with a modified polymer such as acrylic, polyvinyl acetate and ethylene vinyl acetate. • Synthetic organic polymers are used as binders. • Polyester-sterin, acrylic and epoxies -Polyester recines; low price -Epoxy recines; advantages such as adhesion on expensive, wet surfaces • Various fibers such as glass fiber and metal fibers (forperformance)
Classification of polymerconcrete • PolymerConcrete(PC): • -The content of the polymer is generally 5-15% of the total weight. The time required for the surcharges and maximum durability can be easily changed from a few minutes to a few hours by adjusting the catalytic system and temperature. • PolymerModifiedConcrete(PMC) • -PPCC (Polymer-Portland Cement Concrete - LMC ( Latex Modified Concrete ) • -A portion of the mixing water is replaced with a latex polymer emulsion. • PolymerImpregnatedConcrete(PIC) • -Since the cavities are shown as the main responsible for low strength and durability in concrete, filling of these cavities with polymer will increase the strength and durability of concrete. However, it is necessary to use low viscosity polymer in polymer impregnated concretes due to the continuous and filled-up structure of the cavity in the concrete and the fact that the cavities are notcompletely empty.
PolymerConrete(PC) • Stress-change behavior is a significant variable depending on the chemical structure • Modulus of elasticity, vary between 20 and 50 Gpa • The fracture deformation in the draw is usually 1%. • The shrinkage deformations are high for the polyester based binder, low for the epoxy base.
ReasonforUsePolymerConcrete • In case of severe chemical effects, this type of concrete provides high durability with sufficient durability and polymer concrete coatings are effective in preventing reinforcement corrosion in industrial floors and bridge decks.
UsageAreasPolymerConcrete • Polymer concrete is used mostly in industrial concretes, floor coverings and repair works due to having high early strength and elasticity modulus and good chemical resistance.
Comparedtotraditionalconcrete, • Latex modified concrete 2-3 times, • Polymer impregnated concretes 3-6 times, • Polymer concretes are 8-20 times more expensive.
PRE-PACKET CONCRATE ERKAN GÜLTEKİN 45103055564
PRE PACKET CONCRATE:Pre-packed aggregate concrete (PAC) is concrete that is made by forcing grout into the voids of a mass of clean ,graded coarse aggregate densely prepacked in form work .PAC is used where placing conventional concrete is extremely difficult ,such as where massive reinforcing steel and embedded itemsare present ,in water repair ,concrete and masonry repair ,or where shrinkage of concrete must be kept to a minimum. The volume of the coarse aggregate in the pre-pact concrete is about 65-70% and the remaining voids are filled with the flowing mortar. The aggregate mixture in this type of concrete has discrete granulometry.
UsePre-PacketConcrate At: Structuralelements of complexgeometry Repairworks Waterretentionstructures Largebuildingelements underwater structures
What are the differences between pre-pact concrete and other concretes? Pre-pact concrete contains more coarse aggregates than normal concrete. Therefore, the modulus of elasticity is higher and the shrinkage rate is lower than the normal concrete. This is due to the high amount of coarse aggregate and the coarse aggregate grains being in contact with each other.
What is the self compactıngconcrete ? • Self-compacting Concrete (KYB) is a special type of concrete that can be hard reinforced with its own weight and which can settle in deep sections, can not be compressed by external or external vibrations
SCC MixDesign • 1Large aggregate volume will not be more than 50% of the total volume. Largest grain size <16mm • 2The volume of sand (fine aggregate) will not be more than 40% of the mortar.
SCC MixDesign • 4In order to adjust the viscosity, either the viscous chemical additive (fly ash, silica fume, limestone or granite powder, blast furnace slag) should be used. • 5Mixing water should never exceed 200kg / m3.
UseageAreas • Strengthening projects • Frequently equipped elements • Aesthetic mold designs • Difficult and inaccessible molds • Vibrators are not available
Advantages • Decrease in noise and vibration exposure due to vibration-free application, • Ease of production in prefabricated plants • To increase the durability due to the formation of a gapless structure between concrete and iron reinforcement,
Advantages • Having the advantage of being able to cast a single point within the mold in strengthening the damaged buildings • Eliminate the risk of water participation in order to increase workability on the construction site • It is possible to obtain a homogeneous concrete without air bubbles by preventing decomposition.
Disadvantages • SCCproduction requires rigorous and very strict inspection It makes. • There is no internationally valid standard. For this reason, each country casting according to quality management system.