Concrete and Mortar Composition Quiz

Course Information

• Course Title: Bachelor of Civil Engineering (Civil Engineering Materials)
• Course Code: KNS1042
• University: Universiti Malaysia Sarawak (UNIMAS)
• Faculty: Faculty of Engineering
• Lecturer: Dr. Faisal Amsyar

Chapter 1: Introduction to Concrete Technology - Course Learning Outcomes

• Analyze the characteristics of engineering materials used in civil engineering construction (chapters 1, 3, and 4)
• Develop concrete mix design based on typical environmental conditions (chapter 2) - used for Concrete Lab 1
• Relate and select materials for different applications in civil engineering works

Concrete

• Concrete is a composite construction material made of cement, cementitious materials like fly ash and slag cement, aggregate (coarse and fine aggregates like gravels, and crushed rocks and sand), and water. Sometimes chemical admixtures are also used.
• Concrete is composed of mortar (cement, fine aggregate, and water) combined with coarse aggregate.
• Mortar is a combination of cement, fine aggregate, and water.
• Paste is a combination of only cement and water.

Cement vs. Concrete vs. Mortar

• Cement is a binder used to bind other construction materials together.
• Concrete is made of cement, sand, gravel, and water.
• Mortar is made of cement, sand, and water only.

Types of Concrete Used in Industry

• Normal Strength Concrete (NSC):
  • Composition: Standard mixture of cement, aggregate (sand and gravel) and water.
  • Usage: General construction, residential buildings, pavements, structures that don't require high strength.
  • Strength: Typically 20-40 MPa (MegaPascal)
  • Grading: Based on compressive strength similar to international standards. In Malaysia, MS 523: Part 1: 2005 (or similar British or Eurocode standards).
• High Strength Concrete (HSC):
  • Composition: Similar to normal concrete, but with a higher cement and lower water-to-cement ratio. Admixtures may also enhance performance.
  • Usage: High-rise buildings, bridges, structures requiring superior load-bearing capacity.
  • Strength: Typically greater than 50 MPa.
• High Performance Concrete (HPC):
  • Composition: Mixture designed with specific properties like high strength, durability, and resistance to environmental stressors (e.g., corrosion).
  • Usage: Critical infrastructure (e.g., bridges, tunnels, marine structures), high rise buildings.
  • Strength: Typically above 60 MPa.
• Self-Compacting Concrete (SCC):
  • Composition: High-flow concrete that doesn't require mechanical vibration for formwork filling.
  • Usage: Complex structures with limited access for vibration, heavily reinforced elements or narrow spaces.
  • Strength: Typically 30-60 MPa.
• Light-weight Concrete:
  • Composition: Lightweight aggregates (such as expanded shale or pumice) are used to reduce the density below 1800 kg/m3.
  • Usage: Non-load-bearing structures like roof decks, and partition walls.
  • Strength: Typically 7-17 MPa.
• Reinforced Concrete:
  • Composition: Concrete is strengthened with steel rebar or mesh to better handle tensile stresses.
  • Usage: Common in most structural components (beams, columns, slabs, foundations) of buildings, bridges, or infrastructure projects.
  • Strength: Varies based on design, but typically used for structures needing high tensile strength.
• Precast Concrete:
  • Composition: Concrete components are cast and cured off-site in a controlled factory environment, then transported.
  • Usage: Repetitive modular components in large projects (beams, slabs, panels, and columns).
  • Strength: Generally similar to reinforced concrete, but can be customized.
• Ready-Mix Concrete:
  • Composition: Pre-mixed concrete delivered to the construction site (from a batching plant).
  • Usage: Large-scale construction projects where consistency and quality control are important (highways to bridges).
  • Strength: Can be adjusted to meet project needs, from normal to high strength.
• Green Concrete:
  • Composition: Eco-friendly mixes using recycled materials (or supplementary cementitious materials like fly ash, slag or silica fume).
  • Usage: Sustainable construction practices to minimize environmental impact.
  • Strength: Comparable to conventional concrete.

Water-to-Cement Ratio

• Definition: The ratio of the weight of water to the weight of cement.
• Range: 0.40 - 0.60 in general concrete mixes.
• Importance: The water-cement ratio directly impacts concrete's strength and workability. Lower ratios lead to higher strength but reduced workability, and vice versa

Portland Cement types

• Ordinary Portland Cement (OPC):
  • General construction where rapid hardening isn't needed.
  • Good strength development & suitable for general use.
• Rapid Hardening Portland Cement (RHPC):
  • Faster strength development than OPC (attains high strength in 3 days).
  • Suitable for precast concrete and repairs.
• White and Coloured Portland Cement:
  • Low iron and manganese prevents coloration, typically used for aesthetic finishes such as tiles, flooring, or decorative works.
• Low Heat Portland Cement (LHPC):
  • Produces less heat during hydration, reducing the risk of cracking important for mass concrete projects like dams, bridges, and large foundations.
• Portland-Blast Furnace Slag Cement:
  • Blend of Portland cement with granulated blast furnace slag.
  • Improves durability, and often used in marine structures and projects exposed to sulfates.
• Sulfate Resisting Portland Cement (SRPC):
  • Designed to resist sulfate attacks that cause expansion and cracking
  • Lower in tri-calcium aluminate, the component that reacts with sulfates.
  • Ideal for foundations, sewage treatment plants, and structures exposed to water or soils high in sulfates.
• High Strength Portland Cement (HSPC):
  • Higher compressive strength than OPC.
  • Lower water-cement ratio and finer particles.
  • Used in high-performance structures, such as high-rise buildings, bridges, and tunnels.
• Masonry Cement:
  • Blended with lime or other fine materials for masonry structures. Improved workability and cohesion properties
  • Used for plastering, blocklaying and other non-loadbearing masonry applications.
• Air Entraining Cement:
  • Composition: Introduces air bubbles during production
  • Enhanced durability and resistance to cracking and damage due to freezing-thawing or moisture exposure.

Main Components in Concrete

• Cement: A binder that sets, hardens, and binds other components.
  • Types:
    • Hydraulic: Sets and hardens in the presence of water.
    • Non-hydraulic: Sets and hardens by reaction with carbon dioxide in the air.
• Fine Aggregate (Sand): Small-size granular material filling the voids between larger aggregates.
• Coarse Aggregate (Gravel): Larger pieces of crushed rock or gravel used for strength and stability.
• Water: Essential for the hydration process which is chemically reacting with cement to gain strength. Also important for workability

Process of Concrete production (Manufacturing)

• A diagram explaining the steps in manufacturing concrete, from the initial raw materials to the final product (Ready-Mix concrete)

Test your knowledge on the components and differences between mortar and concrete. Understand the various types of cement, their strengths, and their applications in construction. Delve into the standards and practices specific to the concrete industry, especially in Malaysia.