Concrete Construction Flashcards
What is concrete?
Concrete is the composite material consist essentially of aggregate (coarse and fine) particle embedded in a binding medium
What makes a paste?
Cement + water
What can other additions to concrete include?
Reinforcing steel
What is the function of paste?
To bind the aggregate
What is the process of concrete?
- Mix
- Transport
- Place
- Finish
What are hydration products?
-Hydration products are substances formed when water reacts with a compound, like cement, leading to hardening and strength in concrete.
- They will precipitate to form solids
What are the reactants in making ions and forming hydration products?
Cement phases (C_3S) + H20
What does SEM stand for?
Scanning electron microscope
What is Motar consist of?
Paste + fine aggregate
What does Concrete consist of?
Paste + coarse aggregate
What are advantages of concrete?
- Fire resistant
- Cost effective
- Durable
- Insulator
- Strong in compression
- Made from the most common elements in the Earths crust
- Dampens vibrations
What are disadvantages of concrete?
- Weak tension
- Ugly
- Large self-weight
- Hard to reuse
- Porous material
- Can have long term deformations - creep and shrinkage
- Not widely recycled
What is cement clinker?
- Cement clinker is a solid material produced in the manufacture of Portland cement as an intermediary product.
- Clinker occurs as lumps or nodules
How can we make better concretes?
- Crack resisting concrete
- Hydrophobic concrete
- Self-healing concrete
- Low-carbon concretes
- Self-sensing concrete
How do voids appear in cement?
Voids come from the remnants of the water - left over space (capillary pores)
Why can voids be bad?
Makes porous concrete → corrosion
What are the raw materials used in cement?
Limestone and clay
What is the most common cement?
Portland
What does clinker consist of?
- Calcium Silicates
- Aluminates
- Ferrites
What controls the setting time of cement?
Gypsum
What is aggregate made of?
Sand and gravel
Plasticisers what are they?
Give concrete more workability and allow it to be moulded
What’s hydrophobic concrete?
Repels water
How much CO2 does cement contribute to?
The manufacture of cement produces about 0.9 pounds of CO2 for every pound of cement
