Waste utilization as an effective and ecologically friendly approach to control chloride-induced corrosion in reinforced concrete

Authors: D.A. Koleva, K. van Breugel, J.H.W. de Wit
Paper category: conference
Book title: Concrete Durability and Service Life Planning – ConcreteLife’09
Editor(s): K. Kovler
Print ISBN: 978-2-35158-074-5
e-ISBN: 978-2-35158-085-1
Publisher: RILEM Publications SARL
Publication year: 2009
Pages: 319 – 326
Total Pages: 8
Language: English

Abstract: This paper reports on the preliminary investigation of waste product utilization by means of partial cement replacement in reinforced concrete with the waste product “red mud”. The study mainly aimed at studying corrosion behaviour of the embedded steel in chloride environment (10% NaCl solution), coupled with monitoring microstructural changes in the bulk cement-based matrix, as well as the steel/cement paste interface in the presence of red mud.
Reinforced mortar specimens, with and without red mud addition, were cast and monitored. The electrochemical behaviour of the embedded steel (construction steel FeB500 HWL) was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). Electron microscopy (ESEM), image analysis and EDX analysis were used to evaluate the microstructural properties.
The main conclusion from this initial investigation is that the addition of 20% red mud, as cement replacement in the mortar mixture, significantly delays corrosion initiation i.e. in the specimens containing red mud, corrosion started after 70 to 85 days, while in the “control” (corroding) samples corrosion was initiated 10 to 15 days after immersion in NaCl. Furthermore, the addition of red mud slightly decreases porosity and pore size distribution in the bulk cementitious matrix through increasing the chloride binding capacity of the latter. Consequently, red mud addition is believed to considerably improve the corrosion resistance of reinforced concrete in chloride containing environment.

Online publication: 2012-05-16
Publication Type: full_text
Public price (Euros): 0.00