HARDENED CONCRETE

What is the meaning of W/C ratio?

• Mass of water over mass of cement

• Mass of water over mass of concrete

• Temperature of water over temperature of cement

What is the minimum concrete cover should be done to protect re-bar?

• 10mm

• 40mm

• 25mm

• 35mm

For G20 concrete, what is the correct concrete ratio?

• 1:1.5:3

• 1:3:6

• 1:1:2

• 1:2:4

Purpose of using Plasticiser as admixture in concrete?

• increase workability, maintain strength

• increase workability, decrease strength

Purpose of using Retarders as admixture in concrete?

• Slow down setting time of concrete for transportation

• Speed up setting time of concrete for cold climate

• Increase water content in concrete

• Decrease water content in concrete

Purpose of using Accelerators as admixture in concrete?

• Making the concrete lighter in weight

• Speed up setting time of concrete in cold climate

• Slow down setting time

Purpose of using Air-entraining agents in concrete?

• Produce big bubbles to provide space for water to expand upon freezing

• Produce tiny bubbles to provide space for water to expand upon freezing

Intentionally created, uniformly dispersed and absorbed pressure of the freezing water were the characteristics for?

• Entraped air

• Escalate air

• Entrained air

• Free air

Definition of Curing?

• the process of maintaining satisfactory moisture content and temperature.

• the process of removing water

What is the Curing method that we will use in our Lab Practical 3?

• Wet covering

• Spraying

• Immersion

• Plastic sheets