Title: Performance Criteria for Concrete Resistant to Chloride Ion Penetration
Author(s): Karthik H. Obla
Publication: Materials Journal
Appears on pages(s): 139-148
Keywords: ACI 318; building code; chloride penetrability; corrosion resistance; durability; formation factor; performance specifications; pore solution conductivity; RCPT
Past research showed a correlation between the measured apparent chloride diffusion coefficient determined in accordance with ASTM C1556 and the ASTM C1202 rapid indication of chloride ion penetrability test (RCPT) results. Based on that research, a combination of RCPT and strength criteria was proposed to categorize mixtures based on their resistance to chloride ion penetration. This article proposes specification criteria based on a formation factor to categorize mixtures. The efficacy of using both approaches to categorize 44 concrete mixtures prepared from different portland cements, types and dosages of supplementary cementitious materials, and w/cm is examined. It is found that either approach can be used to categorize mixtures based on their resistance to chloride ion penetration. Specimens from 10 mixtures, moist-cured for over 8 years, were tested for surface and bulk resistivity. The same specimens were immersed in chloride solutions in accordance with ASTM C1556, and chloride-ion contents at specific depths from the exposed surface were measured and compared with the later-age bulk resistivity, early-age RCPT, and estimated formation factor.