Title: CONFUSION ON CHLORIDE LIMITS IN SPECIFICATIONS THAT CHALLENGE THE INDUSTRY

Author(s): Colin L. Lobo

Publication: Symposium Paper

Volume: 308

Issue:

Appears on pages(s): 1-8

Keywords: Building code; Chlorides; Corrosion; Durability; Exposure classes; Specification; Specification limits.

DOI: 10.14359/51689177

Date: 6/1/2016

Abstract:
Chloride limits in concrete are intended to ensure that composition of concrete mixtures do not cause corrosion of reinforcement. This paper provides a brief overview of the requirements in industry standards and discusses some of the test methods used for chloride limits. Estimation of total chloride content in concrete mixtures calculated from the materials and mixture proportions is outlined. It is suggested that the calculated chloride content is a conservative estimate of the available chlorides for corrosion and can be used as an alternative to testing for water soluble chlorides in concrete. The results of a survey of ready mixed concrete producers indicate that chloride limits in concrete are not often required or enforced. Requirements in specifications for concrete vary considerably, are not consistent with Code requirements and often result in contradictory interpretation and requirements.