Engineering Chemistry - Building Materials

Study Notes

Cement is a material with adhesive and cohesive properties, enabling it to bond minerals.
Egyptians used lime and gypsum mortar for pyramids.
Greeks used lime mortar.
Romans produced cement from siliceous-aluminous volcanic ash material.

Raw Materials:
- Limestone: primary source of calcium oxide
- Clay and clay-like materials: source of alumina and silica. These are also added from additional resources like slag, bauxite, iron ore, silica, and sand.
- Gypsum (2-3%): added to regulate setting time.
- Iron source
- Sand
Manufacturing Methods:
- Wet process: Grinding and mixing raw materials in water
- Dry process: Grinding and mixing dry raw materials
Process Description:
- Raw materials are mined, crushed, and transported
- Raw materials are mixed, preheated, and dried
- Clinker is prepared in a rotary kiln
- Clinker is mixed with gypsum
- Final product, cement, is then stored and packaged.

Setting and Hardening
- Setting: Initial stiffening due to gel formation.
- Hardening: Mechanical strength development.
- The initial setting time is 45 minutes, and the final setting is 10 hours.
- Gypsum is added to regulate setting time to slow hydration and prevent very rapid setting.
Clinker Compositions
- Dicalcium silicate (C₂S)
- Tricalcium silicate (C₃S)
- Tricalcium aluminate (C₃A)
- Tetracalcium aluminoferrite (C₄AF)

Regular Portland cement: General construction use (not in soils or groundwater.)
Sulfate resistant Portland cement: Used in construction exposed to sulfate attack.
Rapid hardening Portland cement: For projects needing quick strength development.
Low heat of hydration Portland cement: Low-heat of hydration, slower strength development, good for large structures.
White Portland cement: White colored, no iron oxide.
High alumina cement: Chemical resistance to corrosion.
Oil-well cement: High C₂S and C₃S for low heat of hydration, coarser.
Blended cements (Slag-rich, sand/limestone): Reduce cost, resistance to sulfates, chloride.

History:
- Glass production dates back thousands of years.
- Egyptians and other early civilizations valued glass.
- Modern glass production is efficient and productive.
Properties:
- Amorphous, inorganic, homogeneous, and transparent material.
- Can be molded into various shapes.
Manufacturing:
- Raw materials (sand, limestone, soda ash, etc.) are crushed and mixed.
- Mixed materials are melted in a furnace (typically 1500°C.)
- Molten glass is formed and cooled.
Types of Constructed Glass:
- Common flat glass: Windows, doors
- Float glass: Shopfronts, public places
- Shatterproof glass: Added plastic so it doesn't shatter into pieces.
- Laminated glass: Layers of glass with plastic interlayers.
- Tempered glass: Strong, for impact resistance
- Glass blocks: Walls, skylights.
- Glass wool, fiber glass, insulated glazed units.