Cathodic protection of concrete structures containing calcareous aggregates in tropical‐humid marine environments

Abstract

PurposeTo evaluate the performance of two cathodic protection (CP) systems applied to steel reinforced concrete structures manufactured with calcareous aggregates and exposed to the tropical‐humid marine environment at the Yucatán peninsula in Mexico.Design/methodology/approachRectangular concrete beams were manufactured using a water/cement ratio = 0.65, with and without the addition of NaCl in the mixing water. Specimens subjected to CP, eight to impressed current cathodic protection (ICCP) and eight to sacrificial anode cathodic protection (SACP) were partially immersed in natural seawater during 360 days. The half cell potential (HCP) and the current consumption were recorded during the total exposure time.FindingsThe measured HCP values of the steel rebar in the beams subjected to SACP did not attain protection potential levels. However, the galvanic couple Zn‐steel provided enough current for the protection of the steel. Visual inspection of concrete cores extracted from the beams indicated that corrosion products were not present at the steel‐concrete boundary. On the other hand, the ICCP applied to eight concrete beams provided excellent corrosion protection to the steel rebar.Originality/valueThis work revealed that the SACP system (thermally sprayed zinc) works well in high relative humidity environments and can be successfully used to protect steel reinforced concrete structures manufactured with calcareous aggregates which are endemic of the region and commonly used for infrastructure construction in the Yucatán peninsula.