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Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
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Home > Tools > Frequently Asked Questions
Q. Are the limits on air content that have been commonly used (3 to 7% by volume of concrete) considered satisfactory for nearly all purposes? A. In most air-entrained concrete, values between these limits (based on total concrete volume) have been the aim. (ACI 211.1 considers different exposure conditions and makes some allowance for different sizes of coarse aggregate, requiring higher percentages of air where the mortar portion of the mixture is higher.) To keep within the desired range, reliance has been chiefly on adjusting the amount of air entraining admixture. To achieve the generally desired bubble spacing of 0.2 mm using an air-entraining admixture meeting the requirements of ASTM C260, the dosage should be sufficient to produce 9% air in the mortar fraction of the concrete; the portion that would pass through a 4.75 mm (No. 4) sieve. References: SP-1(02); ACI PRC-211.1-22; ASTM C260 Topics in Concrete: Admixture; Concrete Fundamentals; Mixture Proportioning
Q. Are the limits on air content that have been commonly used (3 to 7% by volume of concrete) considered satisfactory for nearly all purposes?
A. In most air-entrained concrete, values between these limits (based on total concrete volume) have been the aim. (ACI 211.1 considers different exposure conditions and makes some allowance for different sizes of coarse aggregate, requiring higher percentages of air where the mortar portion of the mixture is higher.) To keep within the desired range, reliance has been chiefly on adjusting the amount of air entraining admixture. To achieve the generally desired bubble spacing of 0.2 mm using an air-entraining admixture meeting the requirements of ASTM C260, the dosage should be sufficient to produce 9% air in the mortar fraction of the concrete; the portion that would pass through a 4.75 mm (No. 4) sieve.
References: SP-1(02); ACI PRC-211.1-22; ASTM C260
Topics in Concrete: Admixture; Concrete Fundamentals; Mixture Proportioning
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