QUIZ 2 1. What is meant by concrete? 2. Explain why concrete is the most popular
ID: 1885350 • Letter: Q
Question
QUIZ 2 1. What is meant by concrete? 2. Explain why concrete is the most popular used in construction 3. Discuss 3 factors affecting workability. 4. It is important to control the workability of concrete Please elaborate this statement in relation to concrete work on site s. With the aid of sketches, outline the procedure in 6. What are the functions of formwork and state the two 7. Segregation is when the aggregates separate from the rest conducting compacting factor test types of formwork. of the concrete. This causes weakening and excessive curling and shrinkage. What are the possible reasons to this phenomenon? s. With reference to the Tables and Graphs provided, apply the DOE method to design a concrete mix for a reinforced concrete structure based on the specifications below: Specified com e strength at 28 days 45MPa OPC ement t Coarse and finea Slu Maximum a Bulk s shed 70 100mr 20mm 2.75 50 te ate size ific of aggregate passing 600um sieveExplanation / Answer
Q.1
Concrete is the most used construction material in the world. It is a composite material made up of fine aggregates, coarse aggregate and bonded together with the fluid cement that hardens after drying up. Concrete has very high compressive strength, but low in tensile strength, therefore steel reinforcement is used where ever tension stresses are present.
Q.2
When compared with the other construction materials such as wood and steel, concrete is durable and cost-effective. Concrete has a very good workability and can be created easily at any place. It can be molded into any shape and takes the required form after hardening.
Q.3
Workability is affected by water content, aggregate shape and use of admixtures.
Higher water content makes high workable concrete.
Round shaped aggregates are more workable than the angularly shaped aggregates.
Air entraining agents and other admixtures can be used to increase the workability at the same water moisture content.
Q.4
Workability is the ease with the concrete can be transported and placed and compacted. Therefore higher workability means more ease, and therefore it is important to control the workability at the site.