PERMEABILITY OF HIGH-STRENGTH CONCRETE CONTAINING LOW CEMENT FACTOR

This study examined the influence of American Society for Testing and Materials (ASTM) Class C fly ash on concrete permeability. A plain portland cement concrete mixture was proportioned to have a 28-day compressive strength of 40 MPa. Other concrete mixtures were proportioned to have cement replacement with Class C fly ash in the range of 0 to 70 percent by weight. Compressive strength, air permeability, water permeability, and chloride ion permeability were evaluated for each concrete. The Figg method was used to assess air and water permeabilities. Chloride ion permeability was measured in accordance with ASTM C 1202. Air permeability of plain portland cement concrete was lower than that for concrete containing fly ash at the age of 14 and 28 days. At 91 days, the 55 percent fly ash mixture displayed the highest resistance to air permeability. Fair resistance to water permeability was noted in all concrete mixtures up to 40 days. Maximum resistance to water permeability was observed for the 35 percent fly ash mixture at ages of 28 and 91 days. At the 2 month age, chloride ion permeability of all mixtures except the 74 percent fly ash mixture was rated "moderate" or "very low" in accordance with ASTM C 1202 criteria. When curing was extended by 1 month, the fly ash concrete mixtures with fly ash to cementitious materials in the range of 18 to 55 percent showed lower chloride ion permeability than the concrete without fly ash. A similar trend was obvious at 1 year.

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  • English

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  • Accession Number: 00721076
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 12 1996 12:00AM