CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionHYDRAULIC CEMENTSHYDRAULIC CEMENTSCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionRead Chapter 6CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionGypsum CementGypsum CementCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionLime CementLime CementCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionPortland Cement A hydraulic cement capable of setting, hardening and remaining stable under water. It consists essentially of hydraulic calcium silicates, usually containing calcium sulfate.A hydraulic cement capable of setting, hardening and remaining stable under water. It consists essentially of hydraulic calcium silicates, usually containing calcium sulfate.CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionPortland Cement 01000200030004000500060001900 1950 2000 2050Million tonnesGlobal production of Portland CementCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionPC manufactureRaw Materials:2/3 calcareous materials (lime bearing) - limestone1/3 argillaceous materials (silica, alumina, iron) - clayCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement manufacturingCement manufacturingLimestone(CaO, MgO, SiO2)Clay(SiO2, Al2O3, Fe2O3)Iron oreFe2O3MILLT ≈ 1450 ºC = 2640 ºFCLINKERGypsum(~5%)Final grindingPORTLANDCEMENTOthers(SiO2, energy)CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionManufacturing ProcessManufacturing ProcessCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement FactoryCement FactoryCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement FactoryCement FactoryCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionClinker productionClinker productionTypical rotary cement kiln equipped with preheater and precalciner.Mass proportionLimeAlite (C3S)Belite (C2S)CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionLimestone(CaO + SiO2+ Fe2O3+ CO2)Clay(SiO2+ Al2O3+ Fe2O3+ H2O)3CaO.SiO22CaO.SiO23CaO.Al2O34CaO.Al2O3.Fe2O3C3SC2SC3AC4AFRaw materials Compounds AbbreviationOther(e.g. Rice husk: SiO2)Clinker compositionClinker compositionCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionProduction ProcessProduction ProcessProduction of cement is responsible for ~8% CO2emissions in the WorldCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionClinker production: CO2emissionsClinker production: CO2emissions• Calcination reactionCaCO3 CaO + CO21kg  0.56kg + 0.44kg• For 1000kg of CaCO3:– 440 kg CO2(due to the chemical reaction only)– 560kg CaO• Energy consumed by the reaction= 3.16 GJ per ton. CaO• Coal  ~93kg CO2/GJ • 560kg CaO  1,77 GJ  ~ 165kg CO2– Total = ~605 kg CO2(per ton. CaCO3calcined)• About 815kg CO2are generated for every 1000kg of clinkerproduced– Calcination (chemical reaction) = ~52%, Energy use = ~48%CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement production: CO2emissionsCement production: CO2emissionsCement productionCO2emissionsCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement notation:CCaOSSiO2AAl2O3F Fe2O3HH2OCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCement CompositesC3S = 3CaO.SiO2C2S = 2CaO.SiO2 C3A = 3CaO.Al2O3C4AF = 4CaO.Al2O3.Fe2O3HydrationHydrationcement+waterdissolution precipitationCourtesy: Prof. Karen Scivener, EPFLCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCHEMICAL REACTIONS2C3S + 6H --> C3S2H3 + 3CH + 120 cal / g2C2S + 4H --> C3S2H3 + CH + 62 cal / gC3A + CSH2 --> Ettringite + 300 cal / gImportant!!!CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionMain Components of Portland CementMain Components of Portland CementMain Components of PC amount notes C3S 50% very reactive compound, high heat of hydration, high early strength C2S 25% low heat of hydration, slow reaction C3A 10% problems with sulfate attack, high heat of hydration C4AF 10% gypsum 5% used to control the set of cementCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionSOLIDS IN CEMENT PASTE-Calcium Silicate Hydrate Notation: C-S-HC/S Ratio: 1.5 to 2.0Main Characteristics:High Surface (100 to 700 m2/ g) ----> High Van der Walls Force -----> Strength.Volume: 50% to 60%CE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionC-S-HC-S-HCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionSOLIDS IN CEMENT PASTE-Calcium Hydroxide (portlandite)Ca(OH)2Volume: 20% to 25%Low Van der Walls force,problems with durability and strengthCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionCalcium HydroxideCalcium HydroxideCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionSOLIDS IN CEMENT PASTECalcium Sulfoaluminate HydratesVolume: 15% to 20%first: ettringiteafter: monosulfate hydratedCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionEttringiteEttringiteCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionHydration EvolutionHydration EvolutionCE 165: Concrete Materials and Concrete ConstructionCE 165: Concrete Materials and Concrete ConstructionMain Components of PCMain Components of PCMain Components of PC amount notes C3S 50% very reactive compound, high heat of hydration, high early strength C2S 25% low heat of hydration, slow reaction C3A