CONCRETE PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 16. CONCRETE

 

A Concrete mix design Cement is a key material in construction. It consists of a very fine powder. When water is added to cement, a chemical reaction occurs, and the cement begins to set – it starts to become solid. The most widely used cement-based material is concrete, which is made from cement, fine aggregate (sand), coarse aggregate (gravel) and water. After concrete has set, it needs time to reach its structural strength – the strength needed to perform effectively. Generally, engineers consider that this strength is reached after 28 days – a point called 28-day strength. B Reinforced concrete Reinforced concrete (RC) structures contain steel bars. Steel reinforcement is needed mainly because concrete is weak in tension – that is, bad at resisting stretching forces. As steel is strong in tension, reinforcing bars overcome this weakness.     EXERCISES 16.1 Find words and expressions in A opposite to match the descriptions (1-10). 1. gravel used in concrete ____________________ ____________________ 2. sand used in concrete ____________________ ____________________ 3. powder that enables concrete to set ____________________ 4. mixing concrete accurately ____________________ 16.2 Complete the textbook extract about a type of prestressed concrete using the words in the box. Look at B opposite to help you. cast formwork pouring prestressing structural concrete in-situ precast reinforcement     Prestressing techniques In the production of reinforced concrete components, the process of (1)_________ usually involves holding the (2)_________ in tension while (3)_________ the concrete.

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