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Influence of chemical admixtures on the corrosion of rebars in cracked concrete



Author(s): B. Sangoju, R. Gettu, B.H. Bharatkumar
Paper category: Conference
Book title: 2nd International conference on Microstructural-related Durability of Cementitious Composites
Editor(s): Guang Ye, K. Van Breugel, Wei Sun, Changwen Miao
Print ISBN: 978-2-35158-129-2
e-ISBN: 978-2-35158-123-0
Publisher: RILEM Publications SARL
Pages: 1102 - 1110
Total Pages: 8
Language: English


Abstract: 
The paper discusses the results of limited laboratory studies on accelerated chlorideinduced corrosion of reinforcement bars in concretes with selected chemical admixtures (polycarboxylic ether superplasticizer, PCE SP, and calcium nitrite inhibitor, CNI), as well as reference concrete. The effect of the crack and the crack width on corrosion is studied using U-shaped specimens with surface crack widths of 0.2 and 0.4 mm. The specimens were cast with a deformed bar of 12 mm diameter and 20 mm clear cover. They were subjected to 10V constant voltage for a specified duration while submerged in 3.5% NaCl solution. In the cracked specimens, rust stains were observed at the cracks followed by longitudinal cracking. In the case of uncracked specimens, rust stains were observed along the rebar followed by corrosion-induced cracking along the rebar. Visual observations indicated microcell corrosion in the uncracked specimens and macrocell corrosion in the pre-cracked specimens. After the longitudinal cracking, uniform corrosion was observed in both the uncracked and pre-cracked specimens because the corrosion cracks joined leading to a single longitudinal macrocrack along the reinforcement bar. The gravimetric weight loss in the rebars were determined; the results showed lower weight loss in the concrete with the PCE SP than that of the reference concrete whereas the rebar weight loss in the concrete with the CNI is higher.


Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00