Effect of the use of retardant chemical additive in concrete on rebar corrosion

Reinforced concrete (RC) is one of the most widely used building materials. However, RC, especially in coastal seaside or humid environments, can suffer reinforcement corrosion with the result that the reinforcement fails to perform its function over time. The effect of a retarder additive used to eliminate loss of consistency in hot, windy and humid weather on the corrosion of RC elements was investigated in this work. Four different concrete types were assessed, with 0%, 1%, 1.5% and 2% additions of the chemical additive. Along with accelerated corrosion and pressure tests, physical properties such as electrical resistivity, water absorption, porosity, unit weight and capillary water absorption were also determined. The results of this work indicate that the use of up to 2% of the setting retarder did not pose a problem in terms of the physical and mechanical properties of the concrete. However, in terms of the frequently encountered corrosion problem, the use of 1.5% is more appropriate. Many chemical additives are used for different purposes in concrete and it is suggested that, alongside physical and mechanical properties, durability characteristics should also be examined when determining the suitable ratios of these additives.