Materials and Structures

, Volume 40, Issue 8, pp 801–811 | Cite as

Drying induced moisture losses from mortar to the environment. Part I: experimental research

  • M. AzenhaEmail author
  • K. Maekawa
  • T. Ishida
  • R. Faria
Original Article


Moisture conditions in the pore structure of hardening cementitious materials are known to have determinant influence on the onset and continuance of hydration reactions. Moisture loss from regions near exposed surfaces may jeopardize the quality of concrete cover in terms of both mechanical and durability issues. In addition, drying shrinkage, a phenomenon directly related to a moisture loss to the environment, is known to be responsible for several surface cracks that impair durability performance and pose aesthetical problems. Furthermore, evaporative cooling that occurs in concrete surfaces in the first minutes just after formwork removal may cause thermal cracking. For the above mentioned reasons, it is important to assess the mechanisms of moisture losses from cement-based materials to the environment, in order to rationally establish curing criteria. This paper describes an experimental campaign conducted with the purpose of better understanding the effect of various environmental conditions on the referred moisture interactions, accounting for influences such as the environmental temperature, the relative humidity (RH), the wind speed and direction, as well as the duration of curing. Numerical simulations with comparisons against test data, as well as some sensitivity analyses, are relegated to the companion paper that follows in this issue.


Cement Moisture Evaporation Evaporative cooling Experimental campaign 


Les conditions d'humidité présentes dans la microstructure des matériaux cimentaires au jeune age ont une influence déterminante sur la prise et la continuation des réactions l'hydratation. La perte d’humidité près des surfaces exposées du béton peut compromettre certaines propriétés mécaniques et la durabilité du béton en surface. Aussi, le retrait de séchage—un phénomène directement lié aux pertes d’humidité dans le béton—peut causer la fissuration du béton, ce qui risque d’affecter sa durabilité et son esthétique. De plus, après le décoffrage, le refroidissement par évaporation peut provoquer une certaine fissuration thermique à la surface du béton. Pour ces raisons, il est important d’évaluer les mécanismes d’échange d’humidité entre les matériaux cimentaires et l’environnement extérieur afin d’établir de façon rationnelle des critères de cure humide.

Cet article décrit une campagne expérimentale réalisée dans le but de mieux comprendre les effets de diverses conditions environnementales sur les interactions d’humidité en considérant l’influence de plusieurs variables telles que la température ambiante, l’humidité relative, la vitesse et la direction du vent, ainsi que la durée de cure humide du béton.

La comparaison de simulations numériques avec les résultats expérimentaux ainsi que plusieurs analyses de sensibilité sont présentées dans un deuxième article publié dans ce numéro (partie 2).



Financial support from the Portuguese Foundation for Science and Technology, through the PhD grant provided to the first author (SFRH/BD/13137/2003) and the Research Project POCI/ECM/56458/2004, is gratefully acknowledged.


  1. 1.
    Selih J, Bremner TW (1996) Drying of saturated lightweight concrete: an experimental investigation. Mater Struct/Mater Construct 29(191):401–405Google Scholar
  2. 2.
    Selih J, Sousa A, Bremner T (1996) Moisture transport in initially fully saturated concrete during drying. Trans Porous Media 24:81–106Google Scholar
  3. 3.
    Kovler K (1995) Shock of evaporative cooling of concrete in hot dry climates. Concrete Int 17(10):65–69Google Scholar
  4. 4.
    Keey R (1972) Drying. Principles and practice. Pergamon Press, Oxford; New York, p 358Google Scholar
  5. 5.
    Hillel D (1998) Environmental soil physics. Academic Press, San Diego, p 771Google Scholar
  6. 6.
    Bories A (1990) Fundamentals of drying of capillary porous bodies. In: S. Kakaç et al (ed) Convective heat and mass transfer in porous media. Kluwer Academic Publishers, The NetherlandsGoogle Scholar
  7. 7.
    Neville A (1995) Properties of concrete. Prentice Hall, Pearson, 844pGoogle Scholar
  8. 8.
    Patel R, Killoh D, Parrott L, Gutteridge W (1988) Influence of curing at different relative humidities upon compound reactions and porosity in Portland cement paste. Mater Struct 21:192–197CrossRefGoogle Scholar
  9. 9.
    Spears R (1983) The 80 percent solution to inadequate curing problems. Concrete Int 22(11):15–18Google Scholar
  10. 10.
    Snyder K, Bentz D (2004) Suspended hydration and loss of freezable water in cement pastes exposed to 90% relative humidity. Cement Concrete Res 34:2045–2056CrossRefGoogle Scholar
  11. 11.
    Sun S, Marrero T (1996) Experimental study of simultaneous heat and moisture transfer around single short porous cylinders during convection drying by a psychrometry method. Int J Heat Mass Transfer 39(17):3559–3565CrossRefGoogle Scholar
  12. 12.
    Uno PJ (1998) Plastic shrinkage cracking and evaporation formulas. ACI Mater J 95(4):365–375Google Scholar
  13. 13.
    Al-Fadhala M, Hover K (2001) Rapid evaporation from freshly cast concrete and the Gulf environment. Construct Build Mater 15:1–7CrossRefGoogle Scholar
  14. 14.
    ACI (2001) Guide to curing concrete. ACI Committee Reports, A. C. Institute, edGoogle Scholar

Copyright information

© RILEM has copyright 2007

Authors and Affiliations

  1. 1.Faculty of EngineeringUniversity of PortoPortoPortugal
  2. 2.School of EngineeringUniversity of TokyoTokyoJapan
  3. 3.Civil Engineering DepartmentFaculty of Engineering of the University of PortoPortoPortugal

Personalised recommendations