Investigation of the Cause and Effect of Air Void Coalescence in Air-Entrianed Concrete Mixes

Abstract

Air entraining admixtures (vinsol or non-vinsol) are used in concrete mixes that will be exposed to freeze-thaw cycles or sulfate attack. Entrained air is intended to improve the durability and resistance of hardened concrete to freeze-thaw cycles. However in many instances a significant loss of compressive strength has been observed in concrete mixes containing non-vinsol admixtures. Mixture forensic analysis has determined air void coalescing to be the main factor in observed low compressive strengths. The result of air void coalescing is the over design of compressive strength to account for the possible lower strengths and decreased confidence in the compressive strengths obtained during the quality control/assurance process.