Rebar corrosion in mortars with high limestone filler content

O.R. BATIC; J.D.SOTA; J.L. FERNÁNDEZ; N. BELLOTTI; R. ROMAGNOLI

ANTI-CORROSION METHODS AND MATERIALS

EMERALD GROUP PUBLISHING LIMITED

Año: 2013 vol. 60 p. 3 - 13

0003-5599

Mineral admixtures can partially replace ordinary portland cement without impairing the properties of concrete. They also influence rebar corrosion. The most common mineral admixtures are: puzzolans, granulated blast furnace slag, calcareous filler, flying ash with high and low lime content, condensed silica fumes and rice hush ash. There is an increasing tendency to incorporate carbonate additions to mortars. In this research, rebars corrosion in mortar containing high proportions of limestone filler (~35%) was studied employing two water/cement (w/c) ratios: 0.50 and 0.65, respectively. Corrosion was investigated by means of electrochemical techniques (corrosion potential monitoring, corrosion rate measurements and electrochemical noise). It was found that rebar corrosion became important as the w/c increased. The presence of calcium carbonate altered the structure of the passive layer on rebars and diminished corrosion rate by depositing a carbonate layer on rebars.