Fundamental Study on Concrete with Increased Air Content
By A. Nishizawa, K. Sakurai, Y. Isaji and K. Kawai
Concrete Journal, Vol.64, No.3, Mar. 2026
- Synopsis
- Aiming to reduce CO2 emissions during concrete production, the authors conducted a fundamental study examining the technical feasibility of concrete that features reduced unit cement content achieved by increasing air content. The study confirmed that increasing the air content by 3% allows for a reduction of approximately 10kg/m3 in the unit water content needed to maintain the same slump. However, to achieve the same compressive strength, the water-cement ratio must be reduced by approximately 3%. If compressive strength is maintained, the other strength characteristics and durability are equal to or greater than those of ordinary concrete. Subsequently, concrete with increased air content was produced at a ready-mixed concrete plant for placement into mock-up members. The experiments showed that after production, there was no significant reduction in air content due to elapsed time or pumping and compaction.
- Keywords:
- Air content, Unit cement content, Unit water content, Compressive strength, Flowability, Workability
