Effect Of Chloride Salt On Reinforced Concrete Structures In Lagos Coastal Environment.

Akindahunsi, A.A. ; Falade, F. ; Afolayan, J.O. ; Oke, I.A. (2009-09)

Staff Publication

Article

This paper identified and documented the deterioration pattern of concrete structures in Lagos coastal environment. It also determined the concentrations of chloride ions and their effects on reinforcements in concrete structures. Water samples were collected from Lagos coastal environment (Tin Can Island and Bar Beach) for the purpose of the experiment. Laboratory analyses of the water samples were carried out to determine their chloride contents. Values obtained for the chloride concentrations were used to prepare different concentrations of chloride solutions used as aggressive curing environments with an increment 015 g/L equivalent analytical sodium chloride. Concrete cubes numbering ninety were cast and cured in the different aggressive environments. 7nos. concrete blocks measuring 100 x 100 x 300 mm embedded with 12 mm diameter high yield bars were cast and cured in the prepared aggressive media. The test blocks were connected in parallel to a D.C rectifier set at 10 volt to accentuate the rate of corrosion. A Half-Cell potential apparatus was used to determine the corrosion potential at intervals of 4 days for a period of 28 days after the initial 28 days of curing. Compressive test values obtained show that chloride does not have much of adverse effect on concrete. The results of the Half-Cell potential readings showed that rebars in 24878.80 mg/L curing tank was the most affected by corrosion with peak average potential reading recorded for rebar as 466.50 mV, this is also confirmed by the tensile test conducted.