Non Destructive Characterisation of Cement Mortar during Carbonation

The objective of this work was to examine the changes in non destructive properties caused by carbonation of CEM II mortar. Samples of CEM II mortar were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2 concentration. We examined the evolutions of the gas permeability, the thermal conductivity, the thermal diffusivity, the volume of the solid phase by helium pycnometry, the longitudinal and transverse ultrasonic velocities. The principal contribution of this work is that, apart of the gas permeability, changes in other non destructive properties have never been studied during the carbonation of cement materials. These properties are important in predicting/measuring the durability of reinforced concrete in CO2 environment. The carbonation depth and the porosity accessible to water were also reported in order to explain comprehensively the changes in non destructive parameters.

Authors:

• Son Tung Pham
• William Prince

Keywords:

• Carbonation
• cement mortar
• longitudinal and transverse ultrasonic velocities
• non destructive tests.

References:

[1] Malhotra VM, Carino NJ, editors, Handbook on non destructive testing
of concrete, 2nd ed, Boca Raton, FL: CRC Press; 2004.
[2] Veronique Baroghel Bouny, Conception des bétons pour une durée de
vie donnée des ouvrages, Association fran├ºaise de genie civil, July
2004.
[3] J.J.Kollek, The determination of the permeability of concrete to oxygen
by the CEMBUREAU method-a recommendation, Materials and
Structures 22, pp. 225-230, 1989.
[4] Association française pour la construction et pour la recherche et les
essais sur les matériaux et les constructions (A.F.P.C.-A.F.R.E.M),
Détermination de la masse volumique apparente et de la porosité
accessible ├á l-eau, in : J.P. Ollivier, editor, Durabilité des béton -
Méthodes recommandées pour la mesure des grandeurs associées ├á la
durabilité, Laboratoires des Matériaux et Durabilité des Constructions,
Toulouse, pp. 121-124, 1997.
[5] Walid Jaafar, Influence de la carbonatation sur la porosité et la
perméabilité des bétons, Dipl├┤me d-études approfondies (Master of
advanced studies), Laboratoire Central des Ponts et Chaussées, Paris,
2003.
[6] Wilhelm Eitel, Silicate science: Ceramics and hydraulic binders,
volume V, Academic press, New York, 1966.
[7] E.G.Swenson, P.J. Sereda, Mechanism of the carbonation shrinkage of
lime and hydrated cement, Journal of Applied Chemistry, Vol.18, Issue
4, pp. 111-117, April 1968.
[8] A.M.Neville, Properties of concrete, London: Ed. Longman scientific
and technical, 1990.
[9] F.Y.Houst, F.H.Wittmann, Retrait de carbonatation, IABSE
Symposium, Lisbon (1989) 255-260.
[10] V.G.Papadakis, C.G.Vayenas, M.N.Fardis, A reaction engineering
approach to the problem of concrete carbonation, AIChE Journal,
Vol.35, Issue 10, pp. 1639-1650, 1989.
[11] V.G.Papadakis, C.G.Vayenas, M.N.Fardis, Fundamental modelling and
experimental investigation of concrete carbonatation, ACI material
journal, Vol.88, Issue 4, pp. 363-373, 1991.
[12] Thierry Mickaël, Modelling of atmospheric carbonation of cement
based materials considering the kinetic effects and modifications of the
microstructure, PhD Thesis, L-école nationale des ponts et chausses,
Paris, 2005.