Investigation for the impact of nature of coarse aggregate on the passive layer formation and corresponding corrosion of reinforcement bars in high performance concrete

• High performance reinforced concrete from different heavy and normal weight aggregates.
• Chloride induced corrosion of steel rebars.
• Recommended values for corrosion estimation of HPRC based on aggregate types.

This research paper deals with the influence of high performance reinforced concrete (HPRC) produced from different heavy and normal weight aggregates on the corrosion rate of steel rebars. Three normal weight and two heavy weight coarse aggregate sources were used in this research. For each type of coarse aggregate, prismatic specimens of 200 × 100 × 100 mm were cast and cured in water tanks with 5% chloride concentration. Identical specimens were also cast from mixtures having the same mix proportions but containing 2% chloride by mass of binder. Through this investigation, it was observed that it is desirable to determine experimentally the corrosion rate of HPRC when various coarse aggregates are used for a specified HPRC mixture with and without the use of silica fume. Experiments performed in this research demonstrated that the type of aggregate has significant influence on the corrosion of HPRC. It is therefore recommended to use the appropriate values for corrosion rate estimation of HPRC based on varying aggregate types in a particular specific concrete mixture. In the absence of such values, however, the corrosion rates may be calculated using the experimental curves presented in this paper.