Concrete

Cement

Binding agent - A grey powder that, when mixed with water, serves as the adhesive that binds the components of concrete together; composed of calcium silicates, iron oxide, aluminium oxide, and gypsum.

Concrete

Composite material - a strong building material with the structural characteristics of stone; strong in compression and weak in tension. Mase by mixing cement, water, and aggregates (sand/gravel). It is widely used in construction due to its durability, strength and low cost.

Cement Ingredients

Calcium Oxide: Made from limestone, it gives cement its strength and ability to bind materials
Silica: Helps cement harden and set when mixed with water, Increasing durability against outside elements.
Alumina: Improves resistance to chemicals (like sulphates and acids) and helps cement withstand high temperatures.
Iron Oxide: Provides the grey colour to cement, adds strength, and assists in merging raw materials during production.
Gypsum: Mixed with the other ingredients after they are heated in a kiln.

Ordinary Portland Cement (OPC)

Most widely used, made from clinker and gypsum, strong and versatile

Portland Pozzolana Cement (PPC)

Blended with pozzolanic materials like volcanic ash, enhances workability and reduces heat, ideal for hydraulic and marine structures

Portland Slag Cement (PSC)

Created by grinding OPC with granulated blast-furnace slag, generates less heat and is resistant to chemicals, suitable for general and marine construction

Sulphate-Resistant Cement

Resists sulphate attacks in areas with high sulphate levels in soil or water, ideal for coastal regions

White Cement

Lower in iron, giving a distinctive white colour used in decorative applications

Concrete Ingredients

Cement: Main binding agent made from limestone, clay, and other materials
Water: Needed to mix with cement; must be free from contaminants
Air: Improves workability, pumpability, and prevents freeze-thaw damage
Aggregates: Bulk materials (mix of rocks & sand) that make up 60-80% of mixture, providing strength.

• Coarse Aggregates: Larger pieces like gravel or crushed stone

• Fine Aggregates: Smaller particles like sand (up to 20mm approx)

Additives: Chemicals added to change properties

• Plasticisers: Improve workability

• Retarders: Slow down setting time

• Accelerators: Speed up setting time

• Bonding Agents, Colours, Hardeners

Supplementary Cementitious Materials: Additional materials like fly ash or slag to improve strength and durability.

Cement Mix Ratio

• Cement: 1

• Sand: 3

• Gravel: 3

• Water: 1/2

Decorative Concrete

Coloured or textured for aesthetic purpose

Self-Compacting Concrete (SCC)

Flows easily, filling complex forms without vibration

Shotcrete

Sprayed onto surfaces, used for tunnels and pools

Pervious Concrete

Allows water to drain through

Eco-Friendly Concrete

Made with recycled materials

Standard Concrete

General-purpose concrete

High-Strength Concrete

Designed for heavy loads

Lightweight concrete

Reduces weight, often used in roofs

High-Performance Concrete

Superior durability and strength

Reinforced Concrete

Contains steel bars (rebar) to improve strength

Precast Concrete

Made in a factory and assembled on site

Reinforced Concrete Beams

Steel bars are strategically placed at the bottom to absorb tension forces, with one bar at the top and several at the bottom for maximum support

Steel reinforcing rods should be located in the parts of the structure that will be experiencing tension

Glass Fibre Reinforced Concrete

Composite of different materials including glass fibre, which is used instead of steel to create a more lightweight cast material that can be finished in several ways.

Pre-Cast Concrete

Made by casting concrete in a controlled environment into reusable molds, which are then cured and transported to the construction site for assembly

Pre-Stressed Concrete

Pre-stressing steel enhances the tensile strength of concrete by applying a compressive force after it hardens. Common applications include bridges, commercial buildings, dams, roads, stadiums, hospitals, parking garages, and multi-story residential buildings.

Reinforced Concrete Slab Formats (5)

1. One-Way Slab: A concrete slab spanning between two parallel beams

2. Beams and girder slab: Uses concrete bearers and joists

3. Ribbed Slab: Features smaller, closely spaced ribs for support

4. Two-Way slab: Spans in two directions, providing support across a square or rectangular area

5. Waffle slab: Has a distinctive grid pattern; A concrete slab spanning between two parallel beams.