103. Modelling the carbonation process of self-compacting concrete

Title: 103. Modelling the carbonation process of self-compacting concrete
Author(s): K. Audenaert, G. De Schutter
Paper category : conference
Book title: 5th International RILEM Symposium on Self-Compacting Concrete
Editor(s): G. De Schutter and V. Boel
Print-ISBN: 978-2-35158-047-9
e-ISBN: 978-2-35158-088-2
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 689 - 694
Total Pages: 6
Nb references: 7
Language: English

Abstract: Air is containing CO2, which, in presence of moisture, reacts with hydrated cement. This reaction could lead to deterioration of the concrete structure, caused by the reduction of the pH of the pore water in hardened concrete from approximately 13 to about 9. This reduction in pH causes depassivation of the steel reinforcement followed by corrosion of the steel if moisture and oxygen are present.
The main influencing factors in the carbonation process are the diffusion of CO2 into the concrete and the amount of hydrated cement reacting with the CO2. These two parameters could be determined based on the concrete composition, degree of hydration and the chemical composition of the cement.
In order to study the carbonation of self-compacting concrete, concrete cubes were made of 16 SCC mixtures and 4 traditional concrete mixtures. Four types of cement (portland cement and blast furnace slag cement), three types of filler (fly ash and two types of limestone filler with a different grading curve) and two types of coarse aggregate are used and the influence of the amount of powder and the amount of water is studied. These concrete cubes were stored permanently in a carbonation room at 20°C, 60% R.H. and 10% CO2. At certain times, the carbonation depth is determined with phenolphthalein and the carbonation coefficient is determined.
Based on the test results, the calculated and experimental carbonation coefficients are compared and discussed.

Online publication: 2009-06-16
Publication type : full_text
Public price (Euros): 0.00