What is the function of foam in foam concrete?

Foam for foamed concrete is made from a concentrated foaming Agent. The foam is made from a foam generator. In the foam generator the foaming agent is diluted in water to make a pre-foaming solution and then the pre-foaming solution is expanded with air into foam. The bubbles are stable and able to resist the physical and chemical forces imposed during mixing, placing and hardening of the foamed concrete. Between 75 and 85% of the bubbles are of 0.3 to 1.5 mm in diameter.