If air content of freshly mixed concrete is,

1).Increased by 1%, then compressive strength will be decreased by 5%

2). Decreased by 1%, then yield of concrete will be decreased by 0.03 m3 per 1 m3.

3).Decreased by 1%, then slump of concrete will be decreased by 12.5mm.

4). Decreased by 1%, then durability of concrete will bedecreased by 10%.