Materials and Structures

, Volume 37, Issue 3, pp 177–183 | Cite as

Shrinkage and creep of masonry mortar

  • J. J. Brooks
  • B. H. Abu Bakar


Shrinkage and creep results are presented for different types of masonry mortars having a wide range of strength. The range of values implies that the type of mortar has an appreciable influence on deformation of masonry. The results are analysed, together with other data obtained from other investigations carried out over several years in the same laboratory, and predictive models developed. Factors quantified are strength, volume/surface/ ratio, time of exposure to drying (shrinkage) and time under load (creep). While creep is unaffected, for a given strength, shrinkage of water-cured mortar is greater than shrinkage of mortar that is cured under polythene. When based on 28-day strength, the average error of prediction for shrinkage is 19% but if based on the strength at the start of shrinkage, the error coefficient is reduced slightly to 16%. Creep is estimated with an average error of 24%.


Shrinkage Pier Mortar Joint Error Coefficient Cube Strength 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Les résultats de retrait et de fluage sont présentés pour différents types de mortiers de maçonnerie ayant une large gamme de résistances. Le type de mortier aurait ainsi une influence négligeable sur la déformation des maçonneries. Les résultats sont ensuite analysés; d'autres données ont été obtenues conjointement à partir d'autres études effectuées pendant plusieurs années dans le même laboratoire et des modèles prédictifs ont été développés. Les facteurs qui ont été quantifiés sont la résistance, le rapport volume/surface, le temps de séchage (retrait) et le temps sous charge (fluage). Alors que le fluage n'est pas affecté, pour une résistance donnée, le retrait du mortier exempt d'eau est plus important que le retrait du mortier exempt d'humidité sous polyéthylène. Lorsque la résistance est fixée à 28 jours, l'erreur moyenne de prévision du retrait est de 19% mais si elle est mesurée en début de retrait, l'erreur est légèrement améliorée (16%). Le fluage est estimé avec une erreur moyenne de 24%.


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  1. [1]
    Brooks, J.J. and Forth, J.P., ‘Influence of unit type on creep and shrinkage of single leaf clay brickwork’, Proceedings of the Third International Masonry Conference, London, 1992 (British Masonry Society, Stoke-on-Trent, 1994) 31–33.Google Scholar
  2. [2]
    Comité Européen de Normalisation, Eurocode 6, ENV [1995] ‘Common Unified Rules for Masonry Structures’, Draft 1996-1-1.Google Scholar
  3. [3]
    British Standard BS 5628, ‘Code of Practice for Use of Masonry: Part 2: Structural Use of Reinforced and Prestressed Masonry’, (British Standards Institution, 1995).Google Scholar
  4. [4]
    American Concrete Institute, ‘Specifications for Masonry Structures: ACI 530.1-88/ASCE 6-88’, (ACI Manual of Concrete Practice, Part 5, Masonry, Precast Concrete, Special Proceesses 1990).Google Scholar
  5. [5]
    Forth, J.P. and Brooks, J.J., ‘Influence of mortar type on the long-term deformation of single leaf clay brick masonry’, Proceedings of the Fourth International Masonry Conference, London, 1995 (British Masonry Society, Stoke-on-Trent, 1995) 157–161.Google Scholar
  6. [6]
    Brooks, J.J., ‘Composite models for predicting elastic and long-term movements in brickwork walls’, Proceedings of an International Conference, 1983, Editor: H. W. H. West (British Masonry Society, Stoke-on-Trent, 1986) 20–23.Google Scholar
  7. [7]
    Brooks, J.J., ‘Composite modelling of creep and moisture movement of masonry’,Mater. Struct., RILEM23 (1990) 15–22.MathSciNetCrossRefGoogle Scholar
  8. [8]
    Forth, J.P., Brooks, J.J. and Tapsir, S.H., ‘The effect of unit water absorption on long-term movements of masonry’,Cement & Concrete Composites 22 (2000) 273–280.CrossRefGoogle Scholar
  9. [9]
    British Standard 4551, ‘Method of Testing Mortars, Screeds and Plaster’ (British Standards Institution, 1980).Google Scholar
  10. [10]
    Brooks, J.J., ‘Time-dependent Behaviour of Masonry and Its Component Phases’ (Final Report, EC Science and Technology Programme, Contract No. C11-0925, Brussels, 1996. Available from the University of Leeds).Google Scholar
  11. [11]
    Forth J.P., ‘Influence of mortar and brick on long-term movements of clay brick masonry’, PhD Thesis, School of Civil Engineering, University of Leeds, 1995.Google Scholar
  12. [12]
    Abu Bakar, B.H., ‘Influence of anisotropy and curing on deformation of masonry’, PhD Thesis, School of Civil Engineering, University of Leeds, 1998.Google Scholar
  13. [13]
    Ross, A.D., ‘Concrete creep data’,The Structural Engineer 15 (8) (1937) 314–326.Google Scholar
  14. [14]
    CEP-FIP Model Code for Concrete Structures 1990, ‘Evaluation of the time-dependent behaviour of concrete’, (Bulletin d'Information No. 199, Comité Européen du Béton/Fédération Internationale de la Précontrainte, Lausanne, 1991).Google Scholar
  15. [15]
    Abdullah, C.S., ‘Influence of geometry on creep and moisture movement of clay, calcium silicate and concrete masonry’, PhD Thesis, School of Civil Engineering, University of Leeds, 1989.Google Scholar
  16. [16]
    Tapsir, S., ‘Time-dependent loss of post-tensioned diaphragm and fin masonry walls’, PhD Thesis, School of Civil Engineering, University of Leeds, 1994.Google Scholar
  17. [17]
    Brooks, J.J., Abdullah, C.S., Forth, J.P. and Bingel, P.R., ‘The effect of age on deformation of masonry’,Masonry International, British Masonry Society11 (2) (1997) 51–55.Google Scholar
  18. [18]
    Brooks, J.J. and Abu Bakar, B.H., ‘The modulus of elasticity of masonry’,Masonry International, British Masonry Society 12 (2) (1998) 59–63.Google Scholar

Copyright information

© RILEM 2004

Authors and Affiliations

  • J. J. Brooks
    • 1
  • B. H. Abu Bakar
    • 2
  1. 1.University of LeedsUK
  2. 2.Universiti Sains MalaysiaMalaysia

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