Paper No. PP5 NIGIS * CORCON 2017 * 17-20 September * Mumbai, India Copyright 2017 by NIGIS. The material presented and the views expressed in this paper are solely those of the author(s) and do not necessarily by NIGIS. Short term test methods to determine chloride threshold using macrocell and lollipop type specimens Deepak K. Kamde Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India deepak.kamde89@gmail.com Abdul Basit Peerzada, Radhakrishna G. Pillai Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India ABSTRACT Chloride induced corrosion is one of the serious mechanism of deterioration of reinforced concrete structures. Chloride threshold (Clth) is one of the important parameters to estimate the corrosion initiation time. Chloride ions from external/surrounding atmosphere travel into the concrete (mostly through diffusion process) and reach the rebar level. When sufficient amount of Clth reaches the rebar, chloride ions disrupts the protective passive layer on the steel surface. Though, Clth is an important parameter to be consider to estimate the service life; Practitioners/engineers generally do not evaluate the Clth before planning/construction. In other words, the performance based approach for durability design of reinforced concrete structure is not adopted. This conservative approach can be because of following reasons, i) the standard methods (say, ASTM G 109) requires a long time for determination of Clth of steel cementitious system, ii) Chloride threshold cannot be generalized for steels; It also depends on many factors like steel type, concrete mix, water to binder ratio, and steel - concrete interface properties and iii) conservative approach of contractors and practicing engineers. This paper introduces the short term chloride threshold test methods for uncoated and cement polymer composite (CPC) coated rebar. For this, macrocell (similar to ASTM G 109) and lollipop type specimens (for linear polarization resistance technique) were cast for following set of steel specimens, i) ‘as – received’ steel, ii) CPC coating on ‘as – received’ steel, iii) rust free/sand - blasted steel surface, iv) CPC coating on sand – blasted steel. Chloride concentration near to the exposed steel surface was determined using guidelines given in SHRP – 330. Using both the test methods, chloride threshold determined for each steel type was found to be approximately same. The test duration to determine Clth was found approximately 30 - 90 days in case of Lollipop type specimens and 50-175 day in case of macrocell specimen. Keywords: Chloride threshold, Reinforced Concrete, short term test method