Characterisation of Early Age Deformations in Cement Paste: Case of Chemical and Autogenous Shrinkage
- 1 University of Douala, Post Graduate Training Unit for Engineering Sciences, Douala, Cameroon
- 2 University of Douala, Higher Technical Teachers’ Training College, Douala, Cameroon
- 3 University of Douala, Post Graduate Training Unit for Engineering Sciences, Douala, Cameroon
- 4 University of Douala, Post Graduate Training Unit for Engineering Sciences, Douala, Cameroon
Abstract
Concrete is commonly seen as a durable and long-lasting construction material. However, the long-term performance of a concrete structure can be greatly compromised by early-age cracking. This work is an experimental contribution to study early age deformations of cement paste. Its aim is, firstly, to develop an experimental dispositive for assessing chemical and autogenous shrinkage, and secondly, to measure these volumetric deformations in cement paste. The setup was done following the gravimetric method of measurement, which exploits the Archimedes’ principle. It is made up of an electronic balance, a data accusation unit, a temperature control unit and a buoyancy bath. Investigations were done on Portland cement (CPA-CEM II) at the following W/C ratios: 0.25, 0.3, 0.35, 0.4 and 0.5. It was noticed that the water-cement ratio does not influence the magnitude of the chemical shrinkage in a significant manner but had a kinetic effect; a lower W/C induces a faster rate of chemical shrinkage. Autogenous shrinkage was discovered to be highly inversely proportional to the W/C and was also noticed to be in a function of chemical shrinkage within the first 2 to 4 hours when the paste was still liquid.
- Bentz, D.P. (2008) A Review of Early-Age Properties of Cement-Based Materials. Cement and Concrete Research, 38, 196-204. https://doi.org/10.1016/j.cemconres.2007.09.005
- Stark, J. (2011) Recent Advances in the Field of Cement Hydration and Microstructure Analysis. Cement and Concrete Research, 41, 666-678. https://doi.org/10.1016/j.cemconres.2011.03.028
- Kovler, K. and Roussel, N. (2011) Properties of Fresh and Hardened Concrete. Cement and Concrete Research, 41, 775-792. https://doi.org/10.1016/j.cemconres.2011.03.009
- Nehdi, M. and Soliman, A.M. (2011) Early-Age Properties of Concrete: Overview of Fundamental Concepts and State-of-the-Art Research. Proceedings of Institution of Civil Engineers: Construction Materials, 164, 57-77. https://doi.org/10.1680/coma.900040
- Lura, P. and Jensen, O.M. (2005) Volumetric Measurement in Water Bath: An Inappropriate Method to Measure Autogenous Strain of Cement Paste. The Portland Cement Association, Skokie, 2925. https://orbit.dtu.dk/en/publications/volumetric-measurement-in-water-bath-an-inappropriate-method-to-m
- Lura, P. and Jensen, O.M. (2007) Measuring Techniques for Autogenous Strain of Cement Paste. Materials and Structures, 40, 431-440. https://doi.org/10.1617/s11527-006-9180-2
- Sant, G., Lura, P. and Weiss, W. (2006) Measurement of Volume Change in Cementitious Materials at Early Ages: Review of Testing Protocols and Interpretation of Results. Transportation Research Record Journal of the Transportation Research Board, 1979, 21-29. https://doi.org/10.3141/1979-05
- Hu, Z., et al. (2013) A Review on Testing Methods for Autogenous Shrinkage Measurement of Cement-Based Materials. Journal of Sustainable Cement-Based Materials, 2, 161-171. https://doi.org/10.1080/21650373.2013.797937
- Lura, P., Jensen, O.M. and van Breugel, K. (2003) Autogenous Shrinkage in High- Performance Cement Paste: An Evaluation of Basic Mechanisms. Cement and Concrete Research, 33, 223-232. https://doi.org/10.1016/S0008-8846(02)00890-6
- Bentz, D.P. and Jensen, O.M. (2004) Mitigation Strategies for Autogenous Shrinkage Cracking. Cement and Concrete Composites, 26, 677-685. https://doi.org/10.1016/S0958-9465(03)00045-3
- Holt, E.E. (2001) Early Age Autogenous Shrinkage of Concrete. Technical Research Centre of Finland, Espoo.
- Beaudoin, J. and Odler, I. (2019) 5-Hydration, Setting and Hardening of Portland Cement. In: Hewlett, P.C. and Liska, M., Eds., Lea’s Chemistry of Cement and Concrete, Fifth Edition, Butterworth-Heinemann, Oxford, 157-250. https://doi.org/10.1016/B978-0-08-100773-0.00005-8