Ground Granulated Blastfurnce Slag Presentation on:
1.What is GGBS? 2.What is PBFC? 3.Why use PBFC? 4.Most important of them all – Durability 5.Applications 6.Market Acceptance of HSPBFC 7.Job References 8.Conclusions 9.Summary 10.Recommendations Overview of Presentation
It is a by-product of iron production. Process: Granulation – rapid quenching with water on molten slag. Rapid cooling prohibits crystals and glassy, non-metallic, silicates and aluminosilicates of calcium formation. Granules Ground / milling – dried granules and ground to suitable fineness using ball mills, vertical mills or high pressure roller press mill. Ground Granulated Blastfurnace Slag The chemical composition is almost similar to OPC. Relevant Standards : BS 6699, GB/T What is Ground Granulated Blastfurnace Slag, GGBS?
Blending between Ground Granulated Blastfurnace Slag (GGBS) with Portland Cement (OPC). Relevant Standards : BS 146, BS 4246, SS 476, SS What is Portland Blastfurnace Cement, PBFC? GGBS OPCPBFC =+
3.1Cost Saving; 3.2Appearance; 3.3Workability; 3.4Durability; 3.4.1Reducing Permeability; 3.4.2Mitigating Sulfate / Chloride Resistance; 3.4.3Mitigating Alkali-Silica Reaction (ASR) Resistance; and 3.4.4Reducing Thermal Stress in Mass Concrete. 3.5 Reduce Pollution; and 3.6Protect Depletion of Natural Resources. 3. Why use GGBS with OPC?
Cement usage S.G. of HSPBFC = 2.96; S.G. of OPC = 3.15; and 6% to 7% saving of cement for the same volume of concrete produced. Medical Costs Reduced risk of chromate allergy; OPC contains Hexavalent chromate, main cause of occupational allergic dermatitis; and Slag (GGBS) is free of Cr 6. Lighting and Heating Reduced power consumption in lighting due to whiter appearance; and Enhanced aesthetics through softening of visual impact on large structures. Appearance 3.1Cost Saving $$$
Colour. Off-white – lighter and brighter colour; More aesthetically pleasing; Safety benefits – visibility for kerbs, traffic barriers, bridges; and Cost saving in utilities bills. 3.2Appearance
3.3Workability Cement paste; and Slag cement produces bigger cement paste, thus the concrete tends to have the following characteristics: Improved Uniformity – flow sluggishly into place without segregation; Improved Pumpability; and Improved Compaction. Higher Fineness, Reduced bleeding during concreting.
3.4Durability 3.4.1Reducing Permeability; Is a measure of how easy it is for water, air and other substance to penetrate concrete. Mitigation: By reducing the porosity of the concrete. Consequences: Severe corrosion of reinforcing steel – leads to expansion; Severe concrete cracking; and Concrete deterioration.
3.4Durability 3.4.2Mitigating Sulfate / Chloride Attack; and Occurs when concrete comes into contact with water containing sulfates / chloride; Consequences: Severe concrete cracking; and Concrete deterioration. Mitigation: By reducing C 3 A; By reducing permeability; and By reducing excessive Ca[OH] 2.
3.4Durability 3.4.3Mitigating Alkali-Silica Reaction (ASR). Occurs when a chemical reaction between the alkalis in OPC and certain siliceous aggregates; Consequences: Severe concrete cracking; and Concrete deterioration. Mitigation: By reducing alkalis (Na and K) in cement use concrete mix; By consuming alkalis in hydration process; and By reducing the availability for ASR.
3.4Durability 3.4.4Reducing Thermal Stress in Mass Concrete Any large volume of concrete with dimensions large enough to require that measures be taken to cope with the generation of heat and attendant volume change to minimize cracking; Consequences: Severe concrete cracking; and Concrete deterioration. Mitigation: By reducing cementitious content; By reducing the amount of OPC; and By reducing the early rate of heat generation and peak temperature.
Production of OPC will produce the following SO 2 and No x ; Acidification of soils and surface waters; and Nitrogen saturation in terrestrial ecosystems. CO and No x ; and Increased ground-level ozone formation. CO 2. Global Warming Gas. Since GGBS is a by-product of Iron production, no additional pollutant generated 3.5Reduce Pollution
GGBS can partially replaced the following for Portland clinker product: Limestone (CaO); Clay or Shale (SiO 2, Al 2 O 3 &Fe 2 O 3 ); and Additives (SiO 2, Al 2 O 3 &Fe 2 O 3 ). 1 mt OPC clinker = 1 mt CO 2 (373 cu.M); Large scale replacement in concrete with slag, an industrial by-products; and Contribution to save the environment. 3.6Natural Resources Please refer to for the details of the cement making process.http://www.cement.org/basics/images/flashtour.html
4.1 Infrastructure The public facilities and services needed to support residential development, including highways, bridges, school, sewer and water system. Services and facilities that support day to day economic activity. Infrastructure includes roads, electricity, telephone service, and public transportation. Infrastructure has traditionally been provided and maintained by the government. However, some nations are currently experimenting with privatization of some elements of the infrastructure as governments seek to cut their expenditures. 4.Most Important of All – Durability
4.2 Requirements Public transportation MRT line Road Bridges Ports Services Water reclamation plant Dam Sewage plant 4.Most Important of All – Durability
4.2 Concerns – Environmental exposure Pollution Acid rain; Carbon monoxide; Sulfate; Seawater; and Deicing chemicals. Exposure Freezing and thawing; Varying moisture conditions; and Abrasive loading. 4.Most Important of All – Durability
4.3 Design criteria The longevity of the structure should depend on the following: Quality control of materials (raw material selection); Methods and design – concrete mix design; and Construction practices. 4.Most Important of All – Durability
4.3 Design criteria Determining factors of materials selection: Cementitious Materials: Portland cement with flyash; Portland cement with silica fume; or Portland cement with GGBS. Factors: Exposure; Strength requirement; Need to reduce ASR; and Need to reduce thermal gradient. 4.Most Important of All – Durability
4.4 Fundamental factor in creating durable concrete To use the following in combination with Portland cement: Pozzolans; Ground granulated blastfurnace slag (GGBS); Chemical admixtures and Proper selection of aggregate. Proportion; Hardness; Grading; Shape; Size; and Phase composition. 4.Most Important of All – Durability
4.4 Performance based specification Definition of concrete value: Maturity; Permeability; Air-void structure quantification; Sulfate resistance; Chloride penetration; Strength; and In situ performance. Knowledge needed: Minimal maintenance for any desire service life in any environment. 4.Most Important of All – Durability
4.5 Reason for choosing GGBS with Portland cement Reasons: High consistency – no stringent process control; Easily available; Low heat of hydration; Able to reduce alkali-silica reactivity (ASR); Sulfate resistance; Create a much denser, less permeable concrete; Slower setting time – helps in joint sawing and Good workability. 4.Most Important of All – Durability
Aggressive environment such as: Marine environment either Offshore, Coastal and Undersea structures Sewerage Treatment Plant Drainage Systems Underground Structures Mass Concreting such as: Raft Foundations Hot Weather Concreting Bored Piling Dams and Large Infrastructures 5.Applications
6.Market Acceptance of GGBS cement 6.1Widely recognized and specified as an approved specialty cement by local authorities such as:
6.Market Acceptance of GGBS cement 6.2It has also gained acceptance among local and foreign consultants such as:
6.Market Acceptance of GGBS cement 6.2There is a growing awareness that HSPBFC is suitable for use in: SubstructureUndersea Coastal structureUnderground
Sri Lanka Rantembe Dam, Sri Lanka; Brunei Brunei MLNG; and Jerudong Park. Malaysia Bintulu MLNG. Thailand Royal Thai Navy Dry-dock. China Tangshan-Tianjin Expressway connecting bridge ; and Jinan Kaiyuansi Tunnel 7.Project References
Naval Base Changi Naval Base Undersea Structure Tuas Undersea Cable Tunnel. 7.Project References – Singapore
Hospitals New K K;Tan Tock Seng; Changi Hospital; andThomson Medical Centre Sewerage Treatment Plants Seletar;Kranji; Ulu Pandan; andBedok Container Port PSA Pasir Panjang. MRT North-East Line. 7.Project References – Singapore
Condominiums Scott 28;Trellis Tower; Costa Rhu; Aspen Heights; andGrange Heights. Road Interchange Jalan Ahmad Ibrahim / Upper Jurong Road; Holland / Farrer Road; and Tuas West Road Interchange. Commercial Buildings Bank of China Biopolis Capital Tower; Church Street DBS HQ; MOE HQ; NTUC; Synergy Twin Tower; and Suntec City Officer Towers. 7.Project References – Singapore
Overseas – Reports from Slag Cement Association Charenton Canal Bridge – Louisiana – Bridge; Owner – Louisiana Dept. of Transportation and Development; Uses slag cement in lieu of flyash/silica fume; Uses 50%/50% Portland/Slag blend; Design criteria – low permeability (high durability); LaDOTD HPC specifications: Total air content = %; Slump = 5+3 inches; 56-day = <2,000 Coulombs; Compressive 28-day = 29 MPa; Minimum cement factor = 228 kg/m 3 ; and Maximum w/c = Project References – From SCA Source:
Overseas – Reports from Slag Cement Association Route 64 – Smithburg, Maryland – Bridge; Owner – Maryland Dept. of Transportation and Development; and Uses 60%/40% Portland/Slag blend. Design criteria: Low permeability (high durability); 75 year service life; Shrinkage resistance; Prevent corrosion; and ASR resistance. 7.Project References – From SCA Source:
Overseas – Reports from Slag Cement Association MarylandDOTD HPC specifications: Total air content = %; 28-day = <2,500 Coulombs; Compressive 28-day = 29 MPa; Minimum cement factor = 191 kg/m 3 ; and Maximum w/c = Project References – From SCA Source:
Advantages of using of GGBS/OPC Durability; Reduce peak temperature in mass concrete; Increase delay in peak temperature in mass concrete; and Reduce temperature gradient within mass pour by lowering cooling rate. Compressive Strength of GGBS/OPC 7 days 80% of OPC; 28 days almost the same as OPC; 56 days 5-8% higher than OPC; and Much higher in situ early strength in mass concrete as compared to the current practice in concrete testing. 8.Conclusions
Chloride Resistance of GGBS/OPC Up to 5 times reduction in chloride permeability as compared to OPC; and Better chloride resistance than Sulphate Resisting Concrete (SRC) and comparable to silica fume concrete. Sulphate Resistance of GGBS/OPC Perform better than SRC; and Reduce Alkali-Sulphate Reaction of Concrete. Selection of GGBS/OPC General construction: 20-40% GGBS (OPC substitute); Mass concrete: 60-70% GGBS (generally 65-75%); Chloride/ Sulphate resisting: 70% GGBS (BRE digest 250 up to class 3); and ASR resisting: 65% GGBS. 8.Conclusions
Only GGBS/OPC with >65% GGBS will give you the full benefits of low heat and durability. 8.Conclusions
GGBS Technology: Durability; Low heat; High long term strength; Environmental friendly; Aesthetics; Less maintenance; and Cost/energy saving. 9.Summary Summary
10.Recommendations Concrete ApplicationSlag Cement Concrete paving25 – 50% Exterior flatwork not exposed to deicer salts25 – 50% Exterior flatwork exposed to deicer salts with w/cm = – 50% Interior flatwork25 – 50% Basement floors25 – 50% Footings30 – 65% Walls & columns25 – 50% Tilt-up panels25 – 50% Pre-stressed concrete20 – 25% Pre-cast concrete20 – 25% Concrete blocks20 – 25% Concrete pavers20 – 25% High strength25 – 50% ASR mitigation25 – 70% Sulfate resistance Type II equivalence25 – 50% Type V equivalence50 – 65% Lower permeability25 – 65% Mass concrete50 – 80% Source:
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