Resistance of High-Quality Concrete (HQC) to Chloride Ion Penetraion
Tarun R. Naik, Frederick H. Gustin and Shiw S. Singh
Appears on pages(s):
air-entrainment; chlorides; compressive strength; concretes; cores; fly
ash; silica fume
A research program was carried out to evaluate the chloride-ion penetration of both air and non-air entrained concretes made with mineral admixtures as partial replacements of cement. Two series of investigations (Series 1 and Series 2) were carried out. The mixtures were proportioned to have 28-day strengths of 35 MPa for Series 1 and 69 MPa for Series 2. Chloride-ion penetration was determined in accordance with ASTM C 1202. Series 1 mixtures contained a Class C fly ash whereas Series 2 mixtures contained the fly ash and silica fume. In general, all the concrete mixtures, with or without mineral admixtures, exhibited low values of chloride-ion penetration. In this work, a concrete containing 37% Class C fly ash showed results comparable to a concrete containing 11% Class C fly ash plus 8 % silica fume with respect to chloride-ion penetration. The chloride-ion penetration of high-quality concrete system was found to be unaffected when silica fume concentration was increased from 8 % to 11% .