How do you handle concrete that swells like yeast?
This misfortune turns up occasionally and unexpectedly. Sometimes the concrete contains an admixture that entrains or generates a large amount of air. Another thing that can happen is that a concrete that contains an air entraining agent is mixed with another admixture which is used for some other purpose but which also entrains air and the total amount entrained is excessive. Another possibility is that aluminum pipe has been used for pumping and the abrasion of aluminum releases particles that react with the alkalies of the cement to generate hydrogen gas. In any of these cases the important thing is to get rid of the cause of the swelling. There is virtually nothing that can be done to get rid of the vast amount of air or gas once it has been generated.