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1. SELF COMPACTING CONCRETE: TABLE OF CONTENT: INTRODUCTION HISTORY OF SCC DEVELOPMENTS, RECENT DEVELOPMENT AND FUTURE TRENDS PROPERTIES OF SCC MATERIALS USED IN SCC TESTING METHOD USED FOR SCC MIX DESIHN ADVANTAGES AND DISADVANTAGES APPLICATION OF SCC RATES OR COST OF SCC RATIOS OF SCC CODE BOOK CHARACTERISTICS OF SCC TYPES OF SCC QUALITY CONTROL AND QUANTITY CONTROL OF SCC REQUIREMENTS OF SCC LIMITATIONS OF SCC CONCLUSION

2. INTRODUCTION: 1.1 What is self compacting concrete? Self-Consolidating or Compacting Concrete (SCC) is a special type of concrete which can be placed and consolidated under its own weight without any vibration effort due to its excellent deformability, and which at the same time is cohesive enough to be handled without segregation or bleeding. How is self compacting concrete prepared? Mix cement, aggregates, water, mineral admixtures, and chemical admixtures with a focus on achieving a balanced and self-compacting consistency 1.2} USE OF SCC: This property makes it highly suitable for complex structures or areas with dense reinforcement, ensuring a smooth. compact finish effortlessly. Reinforced formed-members. architectural concrete. floors and slabs. 1.3} SHRINKAGE OF SCC: scc tends to exhibit higher shrinkage than conventional concrete due to its higher binder content, which is necessary for achieving high fluidity and cohesiveness, but this can be mitigated through proper curing and the use of shrinkage-reducing admixtures. More unfavourable curing conditions (30 °C, RH = 30%) caused higher shrinkage strains in all SCC mixtures. Nevertheless, SCC with FA replacement exhibited particularly meaningful growth in the shrinkage, by 43%, after 1 day of concrete curing, and 28% after 28 days, compared to curing conditions at 20 °C, RH = 50%.

3. 1.3.1} Types of Shrinkage in Scc : a) Autogenous Shrinkage: This occurs due to the self-desiccation of concrete after final setting, and is influenced by factors like cement content and water-cement ratio. b) Drying Shrinkage: This is the most significant type of shrinkage in concrete, caused by the evaporation of water from the hardened concrete. c) Plastic Shrinkage: This occurs during the early stages of concrete hardening due to water loss from the surface 1.3.2} Factors Affecting Shrinkage in SCC: Higher Binder Content: SCC, with its higher binder content, is more prone to shrinkage than conventional concrete. Water-Cement Ratio: A lower water-cement ratio can help reduce shrinkage. Curing Conditions: Adequate curing can help minimize shrinkage. Admixtures: Shrinkage-reducing admixtures can effectively mitigate shrinkage. Mineral Additives: Using mineral additives like fly ash (FA) can reduce shrinkage, particularly in SCC. 1.3.3} Mitigation of Shrinkage in SCC: a) Proper Curing: Maintaining adequate moisture levels during the curing period can significantly reduce shrinkage. b) Shrinkage-Reducing Admixtures: Using shrinkage-reducing admixtures, such as polycarboxylate ethers (PEC), can effectively decrease shrinkage. c) Optimized Mix Design: Reducing the water content and increasing the aggregate volume can help minimize shrinkage. d) Use of Mineral Additives: Incorporating mineral additives like fly ash (FA) can also reduce shrinkage

4. 1.4} FUNCTION OF SCC: to fill the required space or formwork completely and to produce a dense and adequately homogenous material without a need for vibrating compaction. A self-compacting concrete (SCC) is capable of flowing inside a formwork naturally, allowing it to pass between the reinforcement bars without segregation or blockage and consolidating without the need for internal or external compaction due to the action of its own weight. 1.5} FACTORS AFFECTING IN SCC: Factors affecting it Self-compacting concrete shouldn’t be applied haphazardly. Self-compacting concrete’s performance and behavior can be influenced by the following factors: Warm conditions and The flowability of self-compacting concrete can be decreased over long distances. On-site delays may have an impact on the effectiveness of the concrete mix design. Self-Compacting Concrete may not always increase in flowability as intended, and job site water addition may result in stability issues.

5. HISTORY OF SCC: For several years beginning in 1983, the problem of the durability of structures was a major problem in Japan. To produce durable structures, sufficient compaction by skilled workers is required. However, the gradual reduction in the number of skilled workers in Japan's construction industry has led to a similar reduction in the quality of construction work. One solution for the achievement of durable structures independent of the quality of construction work is the employment of self-compacting which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. The necessity of this type a concrete mix that flows and compacts under its own weight, Self-compacting concrete (SCC),was first developed in Japan in the 1980s by Professor Hajime Okamura at the University of Tokyo to address issues with concrete durability and labor shortages. Studies to develop self-compacting , including a fundamental study on the workability of were carried out by Ozawa and Maekawa at the University of Tokyo. The motivation behind SCC was the declining number of skilled workers in the construction industry, leading to difficulties in achieving proper compaction of concrete in congested reinforced structures. The initial concept was to create a concrete mix that could flow and fill forms without the need for mechanical vibration. Early Development and Testing (1990s): In 1988, Professor Okamura and his team refined SCC with the first practical mix design. And The first prototype of SCC was developed at Tokyo University by Ozawa, using readily available materials for conventional vibrated concrete. In 1991, Dr. Ozawa at the University of Tokyo introduced the first mix design method for SCC. 1990-2000,Research and development of SCC accelerated, with active research in Europe and North America, leading to specifications and guidelines. The Japanese construction industry quickly adopted SCC, especially for highly reinforced structures and infrastructure projects.

6. Adoption in Europe (1990s - 2000s): SCC gained recognition in Europe in the 1990s through research initiatives such as the Brite-EuRam project, which aimed to develop SCC technology for broader applications. Countries like Sweden, France, and the Netherlands contributed to SCC mix design improvements and testing standards. European organizations developed guidelines for SCC production, testing, and quality control. Global Expansion (2000s - Present)*: By the early 2000s, SCC became widely used in North America and other parts of the world. Organizations like the American Concrete Institute (ACI) and the European Federation of National Associations Representing for Concrete (EFNARC) established SCC standards. SCC is now commonly used in precast concrete, high-rise buildings, bridges, tunnels, and infrastructure projects worldwide. 2000s:SCC gained global recognition and increasing use, arly in projects requiring complex formwork or areas difficult to reach with vibrator

7. DEVELOPMENTS,RECENT DEVELOPMENTS AND FUTURE TRENDS: Self-Compacting Concrete (SCC) has undergone significant developments since its invention in the 1980s. Advancements have focused on improving its mix design, sustainability, durability, and performance in construction applications. 3.1 key Developments in SCC Technology: Improved Mix Design Approaches: Early SCC used high powder content (cement and fillers) and superplasticizers to achieve self-compaction. Over time, mix designs have evolved to reduce cement content while maintaining flowability, reducing cost and environmental impact. Incorporation of viscosity-modifying admixtures (VMAs) has improved stability, reducing segregation and bleeding. Sustainability Enhancements: Increased use of supplementary cementitious materials (SCMs) like ‘fly ash, silica fume, ground granulated blast-furnace slag (GGBS), and rice husk ash’ to reduce cement usage and carbon footprint. Introduction of recycled aggregates and industrial by-products to make SCC more eco-friendly. Enhanced Workability and Flowability: Development of new generation ‘polycarboxylate-based superplasticizers (PCEs)’ for better control over fluidity and setting time. Refinements in testing methods, including ‘L-box, U-box, and J-ring tests’, to better assess SCC’s self-compacting properties. Structural Performance Improvements: Improved bond strength with reinforcement, reducing construction defects. Better rheology control, allowing SCC to be used in extreme environments like underwater construction and high-rise buildings.

8. 3.2 Recent Developments in SCC (2020s and Beyond): Green and Eco-Friendly SCC: Development of ‘carbon-negative SCC’ using bio-based materials and carbon capture technology. Research on SCC using ‘geopolymer binders’ (alkali-activated materials) to replace traditional Portland cement. Smart and Self-Healing SCC: ‘Bacteria-based self-healing SCC’, where microorganisms produce limestone to heal micro-cracks. Use of ‘nano-materials like nano-silica and graphene’ to enhance mechanical properties and durability. High-Performance and Ultra-High-Performance SCC (UHPSCC): Introduction of ‘Ultra-High-Performance SCC (UHPSCC)’ with compressive strengths above 150 MPa for extreme applications. SCC with ‘fiber reinforcements’ (steel, glass, or synthetic fibers) for enhanced crack resistance and toughness. Digitalization and AI in SCC Design: Use of ‘Artificial Intelligence (AI) and Machine Learning (ML)’ to optimize mix designs for specific project requirements. Integration of ‘3D printing with SCC’ for rapid construction of complex structures. Application in 3D Printing and Prefabrication: SCC is being increasingly used in ‘automated construction and 3D printing’, allowing for faster and more efficient building processes. Precast SCC elements are being used in ‘modular construction, reducing labor and improving quality control. 3.3 FUTURE TRENDS OF SCC: Future trends in self-compacting concrete (SCC) include increased use of recycled aggregates, exploration of alkali-activated materials, and advancements in superplasticizer technology to enhance durability, sustainability, and performance in various applications, including high-rise buildings and bridges. Sustainability and Green SCC: Carbon-Neutral and Carbon-Negative SCC: Use of ‘carbon capture technology’ in SCC production to reduce emissions. Development of ‘low-carbon binders’ such as ‘geopolymer-based SCC’, replacing Portland cement.

9. Increased Use of Recycled Materials :‘Recycled aggregates 'from construction waste will become more common in SCC. Utilization of ‘waste-based admixtures from industrial by-products like silica fume, fly ash, and GGBS. Bio-Based and Self-Healing SCC: Use of ‘bacteria-based SCC’ that self-heals micro-cracks, increasing durability and reducing maintenance. Integration of ‘biochar and plant-based polymers’ to enhance SCC’s environmental performance. Digitalization and Smart Technologies in SCC: AI and Machine Learning in Mix Optimization: AI-driven algorithms will help optimize SCC mix designs based on project needs, reducing material wastage. Machine learning models will predict SCC performance under different environmental conditions. 3D Printing with SCC: SCC formulations will be tailored for automated 3D concrete printing, enabling rapid and precise construction. ‘On-site robotic SCC printing’ will become common in large-scale projects like housing and infrastructure. Real-Time Monitoring and IoT in SCC: ‘Embedded sensors in SCC’ will monitor curing, temperature, and structural health in real time. Use of ‘smart concrete 'with self-adjusting rheology to adapt to changing site conditions. High-Performance and Ultra-High-Performance SCC (UHPSCC): Ultra-Durable SCC for Extreme Environments: SCC formulations designed for ‘marine, underground, and space construction’. ‘Nano-engineered SCC’ with graphene, carbon nanotubes, or nano-silica for enhanced strength and durability. Fiber-Reinforced SCC (FRSCC): SCC with ‘nano-fibers and hybrid fiber reinforcements’ to improve crack resistance and flexibility. High-performance SCC for ‘earthquake-resistant and impact-resistant structures’. Transparent and Aesthetic SCC: Development of ‘light-transmitting SCC’ for architectural and futuristic building applications. Use of ‘colored SCC and self-cleaning coatings’ for enhanced aesthetics and reduced maintenance.

10. Prefabrication and Modular Construction with SCC* SCC for Mass Prefabrication: More use of ‘precast SCC elements’ in ‘modular and prefabricated buildings’, reducing construction time. SCC for ‘tunnel lining segments, bridges, and high-rise elements’ for faster and safer construction. Self-Adaptive SCC for Robotics and Automation: SCC that can change viscosity dynamically for use in robotic construction systems. AI-controlled mixing and placement of SCC for fully automated building processes

11. PROPERTIES OF SCC: Self-compacting concrete (SCC) is a highly flowable, non-segregating concrete that can spread into place, fill formwork, and encapsulate reinforcement without the need for mechanical vibration. Its properties include: Fresh State Properties: 1.High Flowability: Easily flows into complex shapes and congested reinforcement areas. 2. Self-Leveling :Can spread uniformly without manual effort. 3. Segregation Resistance :Maintains uniformity without separating aggregates and paste. 4. Passing Ability: Can flow through narrow spaces and reinforcement without blockage. 5. Stability: Retains homogeneity during transport and placement. Hardened State Properties: 6. High Strength: Often achieves better compressive and tensile strength than conventional concrete. 7. Durability: Low permeability and high resistance to aggressive environments. 8. Improved Bond Strength: Enhances bonding with reinforcement due to its high paste content. 9. Reduced Shrinkage and Creep: Proper mix design minimizes shrinkage and long-term deformation. 10. Better Surface Finish: Produces smooth and defect-free surfaces without honeycombing.

12. MATERIALS USED IN SCC: Cement: Ordinary Portland Cement (OPC): (Type I, II, or III depending on requirements) Portland Pozzolana Cement (PPC):(for improved durability and reduced heat of hydration) Supplementary Cementitious Materials (SCMs)* (Enhance workability, strength, and durability) : Fly Ash (Class F or C) : Improves flowability and reduces heat of hydration Ground Granulated Blast Furnace Slag (GGBS): Increases durability and sulfate resistance Silica Fume: Enhances strength and reduces permeability Metakaolin: Improves workability and durability Aggregates (Proper grading is essential for achieving self-compaction without segregation) : Fine Aggregates: Natural river sand or manufactured sand (particle size < 4.75 mm) Coarse Aggregates:* Crushed stones with a ‘maximum size of 12-20 mm’ (smaller size preferred for better flowability) Water: Must be clean and free from impurities to ensure proper cement hydration. Chemical Admixtures (Essential for SCC’s high flowability and stability) : Superplasticizers (High-range water reducers): Polycarboxylate Ether (PCE)-based for superior flow and reduced water content .

13. Viscosity Modifying Agents (VMAs):Prevent segregation and bleeding (e.g., cellulose derivatives, welan gum) Air-Entraining Agents (if required):Improve freeze-thaw resistance and workability These materials are carefully proportioned to achieve ‘high flowability, segregation resistance, and self-compaction ’without the need for vibration. GGBS : To improve Rheological Properties. Fly ash : To improve the quality and durability. Silica Fumes: To improve Mechanical Properties. Stone Powder: To increase the powder content.

14. TESTING METHODS USED IN SCC: several specialized tests are used to evaluate the properties of Self-Compacting Concrete (SCC), ensuring its workability, flowability, passing ability, and resistance to segregation. These tests are categorized based on different properties: Flowability Tests: (Filling Ability) ‘These tests assess the ease with which SCC spreads under its own weight’: Slump Flow Test: Purpose: Measures the free-flowing ability of SCC. Procedure: Fill a slump cone and lift it vertical, Measure the final diameter of the spread concrete. Acceptance Criteria: 550–850 mm spread. T50 Slump Flow Test: Purpose: Measures viscosity by recording the time for SCC to reach a 500 mm diameter. Acceptance Criteria: 2–5 seconds. V-Funnel Test Purpose: Measures the ease of SCC flow and viscosity. Procedure: Fill SCC into a V-shaped funnel, Measure the time it takes to empty. Acceptance Criteria: 6–12 seconds. Passing Ability Tests :‘These tests determine SCC's ability to pass through reinforcements and tight spaces’: L-Box Test: .

15. Purpose: Measures SCC’s ability to flow through rebar. Procedure: SCC is placed in the vertical leg of an L-box, Measure the height ratio of concrete at both ends (H2/H1). Acceptance Criteria: ≥0.8. U-Box Test: Purpose: Evaluates SCC’s ability to flow through narrow openings. Procedure: SCC is poured into one chamber and flows into the other through rebar, Measure the height difference between the two chambers. Acceptance Criteria: 0–30 mm difference. . J-Ring Test: Purpose: Assesses passing ability in congested reinforcement. Procedure: SCC is poured inside a J-ring and allowed to flow, Measure the spread and height difference. Acceptance Criteria: ≤10 mm height difference. Segregation Resistance Tests: ‘These tests ensure SCC remains uniform and does not separate during flow’: GTM Screen Stability Test: Purpose: Measures segregation resistance. Procedure*: A sample of SCC is placed in a sieve, The amount of mortar passing through is measured. Acceptance Criteria: ≤15% segregation. Column Segregation Test Purpose: Checks uniformity in different SCC layers. Procedure: A cylindrical mold is filled with SCC, Concrete is divided into layers and tested for density variations. Acceptance Criteria: Minimal variation in density.

16. MIX DESIGN OF SCC: The mix design procedure for self-compacting concrete is based on Indian standard 10262-2008: A mix design for ‘M30 SCC’ (30 MPa strength) is provided below. The mix proportions may vary depending on material properties and specific requirements. Step 1: Selection of Materials: Cement: Ordinary Portland Cement (OPC 43/53 grade). Fine Aggregate: River sand, well-graded. Coarse Aggregate: 12.5 mm downsize crushed aggregate. Mineral Admixture: Fly ash (for better flowability). Chemical Admixture: Superplasticizer (high-range water reducer), Viscosity Modifying Agent (VMA). Water: Potable clean water Step 2: Target Mix Proportioning:

17. Water/Cementitious Ratio: 0.36 Slump Flow Target:650–750 mm L-Box Test Passing Ratio: ‘≥ 0.8’ V-Funnel Test Flow Time: ‘6–12 sec’ Step 3: Mix Procedure: Dry Mix: Mix cement, fly ash, fine and coarse aggregate for 30 seconds. Add Water & Admixtures: Gradually add water while mixing. Superplasticizer Addition: Add superplasticizer (and VMA if needed) while mixing. Mixing Duration: Continue mixing for ‘4–5 minutes’ for uniform consistency. Workability Testing: Conduct Slump Flow, V-Funnel, and L-Box tests. Adjustments: If ‘flowability is low’ → Increase superplasticizer. If ‘segregation occurs’ → Reduce water or add VMA. If ‘passing ability is poor’ → Adjust aggregate proportions. Step 4: ‘Performance Testing’ Perform the following tests before finalizing the mix:- Slump Flow Test: Target ‘650–750 mm’. L-Box Test: Ensure ‘passing ratio ≥ 0.8’. V-Funnel Test: Flow time should be ‘6–12 sec’. Compressive Strength Test: Ensure ‘30 MPa at 28 days’

18. ADVANTAGES AND DISADVANTAGES OF SCC: Advantages of scc : Reduced Permeability: The permeability of concrete structures is minimized, enhancing their resistance to the ingress of water and other substances. Design Flexibility: SCC provides flexibility in designing concrete structures, allowing for creative and intricate designs. Accelerated Construction: Construction using SCC is expedited, leading to faster project completion compared to traditional methods. Vibration-Free Process: The need for vibration is eliminated, streamlining the construction process and mitigating associated challenges. Effortless Placement: Concrete placement becomes effortless with SCC, resulting in substantial cost savings during construction. Improved Construction Quality: The use of SCC contributes to elevated construction quality, ensuring a more robust and reliable end product. Enhanced Durability and Reliability: SCC structures exhibit higher durability and reliability when compared to conventional concrete structures. Reduced Noise and Vibration Issues:

19. Noise from vibration is reduced, consequently minimizing concerns related to hand-arm vibration syndrome and creating a more conducive working environment. Decreased Labor Costs: By using a method that reduces the need for mechanical vibration, SCC lowers labor costs and simplifies the construction process. Disadvantages of scc : ack of Globally Accepted Mix Design Standard: Currently, there is no universally acknowledged test standard for conducting SCC mix designs, leading to variability in approaches. Higher Construction Costs: The construction cost associated with SCC is higher compared to conventional concrete construction methods. Increased Trial Batches and Lab Tests: The utilization of designed mixes in SCC necessitates more trial batches and laboratory tests, contributing to a more extensive testing process. Demand for Precision in Measurement and Monitoring: SCC requires more precise measurement and monitoring throughout the construction process, adding complexity to quality control of concrete. Stringent Material Selection: Material selection for SCC is more stringent, requiring careful consideration and adherence to specific criteria for optimal performance.

20. APPLICATION OF SCC: High-Rise Buildings: Used in structural components like columns, beams, and walls to ensure uniform compaction and avoid honeycombing. Reduces labor costs and construction time in tall structures. Bridges and Infrastructure Projects: Ideal for densely reinforced bridge piers, decks, and abutments. Enhances the durability and longevity of structures subjected to harsh environmental conditions. Precast Concrete Elements: Used in manufacturing precast beams, slabs, and panels for faster and higher-quality production. Improves surface finish, reducing the need for additional treatment. Repair and Rehabilitation Work: Suitable for filling voids and cracks in damaged concrete structures without manual compaction. Commonly used in the restoration of heritage buildings and tunnels. Marine Structures: Ideal for ports, harbors, and offshore platforms due to its resistance to chloride penetration and durability. Tunnels and Underground Construction:

21. Used for tunnel linings, metro rail projects, and underground storage facilities. Ensures proper filling of complex formwork in confined spaces. Industrial Floors and Pavements: Provides a smooth, defect-free finish, reducing maintenance costs. Used in warehouses, factories, and heavy-load-bearing surfaces. Complex Architectural Designs: Enables the construction of intricate and aesthetically appealing structures without visible joints. Used for curved facades, domes, and artistic concrete elements Raft and Pile Foundations. SCC is employed in the construction of raft and pile foundations, where its self-compacting nature enhances the efficiency of the foundation-building process. Structures with Complex Reinforcement: SCC is particularly advantageous in the construction of structures with intricate reinforcement, providing efficient and uniform filling.

22. RATES OR COST OF SCC: Self-Compacting Concrete (SCC) is a specialized type of concrete that flows easily into formwork and around obstructions without the need for mechanical vibration, ensuring a uniform and dense composition. In India, the cost of SCC varies based on factors such as grade, supplier, and location. Here are so me indicative prices from various suppliers. NS Arcus (Jhajjar, Haryana): Product: Gray NS Arcus Fluid Self Compacting Concrete Mix​ aajjo.com+2aajjo.com+2aajjo.com+2 Grade: M-30​ aajjo.com+2aajjo.com+2aajjo.com+2 Packaging Size: 7 Cubic Meters​ Price: ₹5,000 per Cubic Meter​ aajjo.com Minimum Order Quantity: 10 Cubic Meters Rhino Concretes India Pvt. Ltd. (Delhi): Product: Self-Compacting Concrete Special Performance Cement​Trade India Price Range: ₹3,501 to ₹5,500 per Cubic Meter​ Minimum Order Quantity: 7 Cubic Meters​ Beta Ready-mix Concrete Private Limited (Chennai, Tamil Nadu): Product: Self-Compacting Ready Mixed Concrete​betareadymixconcrete.in Price: ₹5,000 per Cubic Meter​ Minimum Order Quantity: 50 Cubic Meters

23. RATIOS OF SCC: Self-Compacting Concrete (SCC) does not have a fixed mix ratio like conventional concrete, as its design depends on various factors such as workability, strength requirements, and local material availability. However, a typical mix design for SCC follows these general guidelines: A common mix design for M30 grade SCC might be: Cement: 1 part (350–450 kg/m³) Fine Aggregates (Sand): 2–2.5 parts (850–1000 kg/m³) Coarse Aggregates (10–12 mm max size): 1.5–2 parts (700–900 kg/m³) Water: 0.35–0.45 part (160–200 liters /m³) Mineral Admixtures: Fly Ash or GGBS: 100–200 kg/m³ (optional) Silica Fume: 5–10% of cement (optional) Chemical Admixtures: Superplasticizer: 1–2% of cement weight Viscosity Modifying Agent (VMA): 0.1–0.3% of cement weight

24. Typical SCC Mix Ratio Example (by weight) For an M40 grade SCC , a mix design could be: Cement: 400 kg/m³ Fly Ash: 120 kg/m³ Fine Aggregate (Sand): 850 kg/m³ Coarse Aggregate: 780 kg/m³ Water: 180 liters /m³ Superplasticizer: 2 kg/m³ Viscosity Modifying Admixture (VMA): 0.3 kg/m³ Key Considerations for SCC Mix Design Lower Coarse Aggregate Content: SCC requires a reduced coarse aggregate content to enhance flowability. Higher Fine Aggregate Content: More sand is needed to prevent segregation. Admixtures: Superplasticizers are crucial for maintaining high flowability while keeping water content low. Powder Content: A high cementitious material content (cement + fly ash/GGBS) improves cohesiveness.

25. CODE BOOK Several international and national codebooks and guidelines provide standards and recommendations for Self-Compacting Concrete (SCC) . Below are some key documents you can refer to: Indian Standards (IS Codes) IS 10262: 2019 – Concrete Mix Proportioning – Guidelines Provides general guidance for SCC mix design. IS 456: 2000 – Code of Practice for Plain and Reinforced Concrete Covers general concrete design principles, including SCC considerations. IS 383: 2016 – Specification for Coarse and Fine Aggregates for Concrete Specifies aggregate properties for SCC. IS 9103: 1999 (Reaffirmed 2021) – Specification for Concrete Admixtures Defines superplasticizers and viscosity-modifying admixtures for SCC. IS 2386 (Part 1 to 8) – Methods of Test for Aggregates for Concrete Includes test procedures relevant to SCC aggregates. Bureau of Indian Standards (BIS) Special Publications SP 23: 1982 – Handbook on Concrete Mixes Helps in SCC mix proportioning and adjustments. SP 34: 1987 – Handbook on Reinforcement and Detailing Useful for SCC applications in reinforced structures.

26. International Codes & Guidelines EFNARC Guidelines (2005) – Specification & Guidelines for SCC A widely accepted international standard for SCC mix design, testing, and applications. EN 206: 2013 – Concrete - Specification, Performance, Production, and Conformity European standard for concrete, including SCC requirements. ACI 237R-07 – Self-Consolidating Concrete (American Concrete Institute) Provides detailed guidelines for SCC design and application. BS EN 12350-8: 2019 – Testing Fresh Concrete - Part 8: Slump-flow Test Specifies SCC workability and flowability tests. BS EN 12350-10: 2010 – Testing Fresh Concrete - L-Box Test Used to measure SCC passing ability and segregation resistance.

27. CHARACTERISTICS OF SCC Self-Compacting Concrete (SCC) is a highly flowable, non-segregating concrete that spreads into formwork without the need for vibration. It has several key characteristics that make it unique: 1. Fresh State Properties High Flowability: SCC flows easily into formwork, filling all spaces without external vibration. Self-Leveling: The mix spreads and levels itself under its own weight. Segregation Resistance: SCC maintains uniformity without separating into layers (no bleeding or segregation). High Passing Ability: Easily flows around reinforcement and complex formwork. 2. Hardened State Properties High Strength & Durability: Due to its dense structure, SCC often has better strength and durability compared to conventional concrete. Low Permeability: Reduces water ingress, improving resistance to chemical attack. Improved Bond Strength: Better adhesion to reinforcement due to higher cement paste content

28. 3. Workability & Rheological Properties Slump Flow: SCC typically has a slump flow of 600–800 mm , much higher than conventional concrete. Viscosity: Controlled by using Viscosity-Modifying Agents (VMAs) to prevent segregation while maintaining flowability 4. Testing & Quality Control Several tests are used to evaluate SCC properties, including: Slump Flow Test (for flowability) V-Funnel Test (for viscosity) L-Box Test (for passing ability) U-Box Test (for filling ability) J-Ring Test (for blocking resistance) 5. Composition & Mix Design Higher Cementitious Content: Uses 350–450 kg/m³ of cement (or a combination of cement, fly ash, and GGBS). Lower Coarse Aggregate Content: To ensure smooth flow and avoid blockages. Superplasticizers & VMAs: Essential for maintaining flowability without increasing water content.

29. TYPES OF SCC: ### 1. *Powder-Type SCC*- Contains a high volume of fine materials like fly ash, limestone powder, or silica fume.- Reduces the water-cement ratio and increases viscosity for stability.- Commonly used where high flowability and resistance to segregation are needed.### 2. *Viscosity Modifying Admixture (VMA) Type*- Incorporates viscosity-modifying agents to ensure stability even with less fine content.- Useful for mixes where local materials do not naturally offer adequate viscosity.### 3. *Combination Type (Powder + VMA)*- Uses both increased powder content and VMAs for improved performance and workability.- Offers better control over flow and resistance to segregation.### 4. *Precast SCC*- Designed specifically for precast concrete products.- Prioritizes early strength gain and surface finish.### 5. *Ready-Mix SCC*- Made for use in cast-in-place applications.- Focuses on ease of transport, placement, and high durability.### 6. *High-Performance SCC*- Tailored to meet demanding structural or durability requirements.- Often used in infrastructure or large-scale projects.

30. QUALITY AND QUANTITY CONTROL OF SCC Quality and quantity control of *Self-Compacting Concrete (SCC)* is critical to ensure performance, durability, and cost-effectiveness. Here’s an overview of the main aspects:---### *Quality Control of SCC*SCC has unique properties compared to conventional concrete, and its quality control focuses on *workability, strength, durability, and **uniformity*.#### 1. *Material Control*- *Cement*: Verify grade and fineness.- *Aggregates*: Ensure proper gradation, cleanliness, shape, and moisture content.- *Admixtures*: Use high-range water-reducing admixtures (HRWR), viscosity-modifying agents (VMA) as per mix design.- *Water*: Use clean, potable water.#### 2. *Fresh Concrete Tests*- *Slump Flow Test*: To assess flowability. Target: 650–800 mm.- *V-Funnel Test*: To evaluate viscosity (filling ability). Ideal time: 6–12 seconds.- *L-Box or J-Ring Test*: To check passing ability and flow around obstacles.- *Segregation Resistance Test*: To verify the mix remains homogeneous during flow.#### 3. *Hardened Concrete Tests*- *Compressive Strength*: Standard cube/cylinder tests.- *Flexural and Split Tensile Strength*: For structural design validation.- *Durability Tests*: Chloride penetration, water absorption, freeze-thaw tests (as applicable).#### 4. *Mix Consistency*- Monitor batch-to-batch consistency.- Regular recalibration of batching plants and mixers.---### *Quantity Control of SCC*#### 1. *Batching and Mixing*- Use *weigh batching* (not volume) for accuracy.- Automated batching plants are preferred.- Mix for the right duration (typically 4–6 minutes in high-speed mixers).#### 2. *Delivery and Placement*- Transport SCC in well-maintained transit mixers.- Avoid delays that may cause setting or segregation.- Place without vibration; ensure proper formwork to resist lateral pressure.#### 3. *Measurement and Tracking*- Record daily quantities of each material.- Monitor yield per batch and compare with theoretical yield.- Use digital systems for inventory and tracking.

31. REQUIREMENTS OF SCC: ### *1. Fresh Properties Requirements (Workability)*To ensure self-compaction without segregation:- *Filling ability*: The ability to flow under its own weight.- *Passing ability*: The ability to flow through tight spaces and around reinforcement without blocking.- *Segregation resistance*: The ability to maintain a uniform composition without separating.These are typically measured by:- *Slump Flow Test*: 650–800 mm (typical range)- *V-Funnel Test*: 6–12 seconds- *L-Box Test*: Ratio (H2/H1) ≥ 0.8- *J-Ring Test*: To assess passing ability---### *2. Material Requirements*To achieve SCC properties:- *Cement*: Similar to conventional concrete, but often with a higher powder content.- *Supplementary Cementitious Materials (SCMs)*: Fly ash, silica fume, or GGBS to enhance flowability and reduce heat of hydration.- *Fine Aggregates*: Higher proportion to reduce segregation.- *Coarse Aggregates*: Well-graded and typically smaller size (10–20 mm) to avoid blocking.- *Superplasticizers*: Essential to enhance flow without increasing water content.- *Viscosity Modifying Agents (VMA)*: Optional, used to improve cohesion and reduce segregation.---### *3. Performance Requirements (Hardened Concrete)*Even though SCC focuses on fresh properties, it must still meet structural requirements:- *Compressive Strength*: As per design, same as conventional concrete (e.g., 30–50 MPa or higher).- *Durability*: Good resistance to permeability, carbonation, and chloride ingress.- *Shrinkage & Creep*: Should be controlled by mix design.

32. LIMITATIONS OF SCC: ### *1. Higher Cost*- *Material cost is higher* due to the use of more cement, fine fillers, and chemical admixtures like superplasticizers and viscosity-modifying agents.### *2. Mix Design Complexity*- *Designing SCC is more complex* than conventional concrete. It requires precise proportioning and testing to achieve desired flowability without segregation.### *3. Sensitivity to Material Variability*- SCC is *very sensitive to variations* in aggregate moisture, fines content, and temperature, which can affect its flow properties.### *4. Risk of Segregation and Bleeding*- If not properly designed, SCC can *segregate* or *bleed*, especially in taller elements or during long pumping distances.### *5. Special Quality Control*- Requires *rigorous quality control* during batching and placement to ensure consistency and performance.### *6. Limited Availability and Experience*- Not all contractors or plants are familiar with SCC, and *lack of experience* can lead to poor application or failures.### *7. Formwork Pressure*- Due to its flowability, SCC can exert *higher lateral pressure* on formwork, requiring stronger and more stable forms.### *8. Delayed Setting*- Some SCC mixes may have *longer setting times*, which can delay construction progress or finishing operations

33. CONCLUSION: Self-Compacting Concrete (SCC) represents a significant advancement in concrete technology, offering superior flowability, stability, and ease of placement without the need for mechanical vibration. Its ability to fill complex formworks and encapsulate reinforcements ensures enhanced structural performance, improved surface finish, and increased durability. Although SCC may involve higher initial material costs, these are often offset by reduced labor, faster construction times, and better long-term performance. Overall, SCC is a sustainable and efficient solution for modern construction challenges.