Consider the following statements for air-entrained concrete: (i) Air-entrainment reduces the water demand for a given level of workability. (ii) Use of air-entrained concrete is required in environments where cyclic freezing and thawing is expectedWhich of the following is TRUE?

Consider the following statements for air-entrained concrete: (i) Air-entrainment reduces the water demand for a given level of workability. (ii) Use of air-entrained concrete is required in environments where cyclic freezing and thawing is expectedWhich of the following is TRUE? Correct Answer Both (i) and (ii) are True

Air Entraining agent:

• These are the admixtures which when used in concrete, forms millions of air bubbles, which act as flexible ball bearings and gives a lubricating effect.
• The entrained air increases the workability of concrete resulting in its greater uniformity.
• The air bubbles formed due to the air-entraining agent act as a fine aggregate and enable the reduction of sand in concrete. The reduction of fine aggregate results in the reduction of water requirement without any ill effect on workability and slump.
• Air-entrained concrete contains billions of microscopic air cells per cubic foot. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes and useful in freeze and thaw resistance.

Both the given statements are correct, hence option 1 is correct