In the present work, contribution of supplementary cementitious materials (SCM) such as sugarcane bagasse ash (SCBA) and fly ash (FA) in the reduction of the corrosion phenomenon in AISI 1018 carbon steel as reinforcement during 24 hours of concrete setting was studied. The design of ternary concrete systems was carried out according to ACI 211.1 method. Ash percentages were 10 and 30% of SCBA and FA combined. During the electrochemical study, corrosion potential (Ecorr ) and electrochemical noise (EN) of AISI 1018 carbon steel was monitored. Time series of current and potential, as well as the corrosion current density (icorr), noise resistance (Rn), localization index (LI) and corrosion rate (Vcorr) were analyzed. Results show that concretes added with SCBA and FA presented a better anticorrosion behavior, especially ternary concrete system added with 10% of combined ash, corrosion rate decreased 55% against the reference concrete.