Carbonation and chloride corrosion of steel reinforcement in natural pozzolan-based mortars

Title: Carbonation and chloride corrosion of steel reinforcement in natural pozzolan-based mortars
Author(s): Jose Pacheco, Gerardo J. Fajardo, Pedro L. Valdez
Paper category : conference
Book title: 2nd International Symposium on Service Life Design for Infrastructures
Editor(s): K. van Breugel, Guang Ye, Yong Yuan
Print-ISBN: 978-2-35158-096-7
e-ISBN: 978-2-35158-097-4
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 773 - 680
Total Pages: -92
Nb references: 17
Language: English

Abstract: Corrosion of steel reinforcement is the main cause of deterioration of reinforced concrete structures. The two most common mechanisms are pitting corrosion due to chlorides contained in either sea water or de-icing salts and general corrosion due to carbonation of concrete. Supplementary cementing materials have been used in order to improve the durability of concrete and reduce repairing costs. Mexico is rich in volcanic zones from which materials with pozzolanic potential may be collected easily. Reinforced mortar specimens with substitutions of cement mass in 0, 10 and 20% of ordinary Portland cement (OPC) by a natural pozzolan were cast, with a water/binder ratio of 0.65. They were cured at 20 °C and RH >90%. A group of specimens were exposed to wet-drying cycles in a chloride-rich solution for 15 weeks and the rest were kept inside a carbonation chamber with conditions of RH 65% and 5% of CO2. The use of this cementing material increased the activation time of steel corrosion, a reduction in the corrosion rate and chloride content of the specimens. On the other hand, results show that a replace of 20% of OPC by pozzolanic material led to the same resistance against carbonation.

Online publication: 2011-04-20
Publication type : full_text
Public price (Euros): 0.00