Concrete

• Concrete is strong in compression but weak in tension . 
• The compressive strength of normal structural concrete used in Malaysia is Grade 30 ( or 30 N/mm2) or about one-tenth that of steel . 
• Its tensile strength is only about one-tenth of its compressive strength . 
• To overcome its weakness in tension , concrete tension members are either : 

Reinforced with steel bars or 

Prestressed with steel wires or cables . 

• Most of the low & high rise buildings in Malaysia are constructed using reinforced concrete . 
• Concrete is highly fire-resistant . 

Properties of concrete 

1. strength varies according to mix proportion 
2. high compressive strength 
3. very good fire protection 
4. low stiffness compared to steel 
5. low strength to weight ratio 
6. low tensile strength . Need to be : 

-reinforced by steel bars 

- prestressed by steel wires / cables 

  7.used for : 

- low rise building frames 

- high rise building frames /