Compatibility Between Cement and Superplasticiser in Combination with Fines, Gypsum and Fly Ash

  • Lorna Stone
  • Rian Pretorius
  • Riaan CombrinckEmail author
Conference paper
Part of the RILEM Bookseries book series (RILEM, volume 24)


The interaction between superplasticisers and cement in concrete is complex and can result in unpredictable and unwanted concrete behaviour. It is known that the positively charged tricalcium aluminate (C3A) component of the cement does not only react with the sulphate (gypsum) present in ordinary Portland cement, but also absorbs the superplasticiser. However, the exact interaction is still not fully understood. This study aims to identify compatibility issues between superplasticisers when exposed to gypsum, fine sand dust and fly ash using the Marsh cone test. The results showed that especially gypsum, which is used in the production process of cement, influence the flow time of the concrete and affects the interaction between the C3A component and the superplasticiser. The more gypsum added, the more superplasticiser is needed to have the same effect. This indicates that the ratio between C3A, gypsum and superplasticiser can result in compatibility issues. Particle size and shape, as in the case of the fly ash, was found to play a role in the effectiveness of the superplasticiser. When fly ash is used to increase the flowability of a concrete mix, the superplasticiser does not result in the same significant improvement in flowability than without fly ash.


Gypsum Superplasticiser Compatibility Marsh cone Flowability 


  1. Aitcin, P.-C., Jolicoeur, C., MacGregor, J.G.: Superplasticizers: how they work and why they occasionally don’t. Concr. Int. 16(5), 45–52 (1994)Google Scholar
  2. ASTM:C939-10: Standard Test Method for Flow of Grout for Preplaced-Aggregate Concrete (Flow Cone Method). ASTM Int. 04(c), 9–11 (2010)Google Scholar
  3. Biggs, B., McCoil, I., Moon, B.: Construction materials. In: Domone, P., Illston, J. (eds.), 4th edn. Spoon Press, Hong Kong (2010)Google Scholar
  4. Flatt, R.J., Bowen, P.: Electrostatic repulsion between particles in cement suspensions: domain of validity of linearized Poisson-Boltzmann equation for nonideal electrolytes. Cem. Concr. Res. 33(6), 781–791 (2003)CrossRefGoogle Scholar
  5. Jayasree, C., Gettu, R.: Experimental study of the flow behaviour of superplasticized cement paste. Mater. Struct. 41(9), 1581–1593 (2008)CrossRefGoogle Scholar
  6. Jayasree, C., Santhanam, M., Gettu, R.: Cement-superplasticiser compatibility - Issues and challenges. Indian Concr. J. 85(7), 48–60 (2011)Google Scholar
  7. Shrivastava, A.K., Kumar, M.: Compatibility issues of cement with water reducing admixture in concrete. Perspect. Sci. 8, 290–292 (2016)CrossRefGoogle Scholar
  8. Yally, P.P., Sam, A.: Effect of sand fines and water/cement ratio on concrete properties. Civ. Eng. Res. J. 4(3) (2018)Google Scholar
  9. Bassioni, G.: The influence of cement composition on superplasticizers’ efficiency. Int. J. Eng. (IJE) 3(6), 577–587 (2010)Google Scholar
  10. Pourchet, S., Regnaud, L., Nonat, A., Perez, J.: Early C3A hydration in the presence of different kinds of calcium sulfate. Cement Concr. Res. 39, 989–996 (2009)CrossRefGoogle Scholar

Copyright information

© RILEM 2020

Authors and Affiliations

  1. 1.Unit for Construction Materials, Civil Engineering DepartmentStellenbosch UniversityMatielandSouth Africa

Personalised recommendations