Interactions between Superplasticizer and Release Agents at the Concrete/Formwork Interface

Samir Bouharoun, Yannick Vanhove, Chafika Djelal, Pascale De Caro, Isabelle Dubois

Centre de Recherche Lafarge, Rue du Montmurier, St Quentin Fallavier, France.
Laboratoire Génie Civil et géo-Environnement (LGCgE)—Lille Nord de France, IUT de Béthune, Rue de l’Université, Béthune, France.
Université de Toulouse, INP, LCA (Laboratoire de Chimie Agro-Industrielle), ENSIACET, Allée Emile Monso, Toulouse, France.

DOI: 10.4236/msa.2012.36055                

Abstract

Improving the knowledge of rheological and tribological characteristics of fresh concrete is important to contribute to the progress of construction sites and the final quality of the work. The objective of this study is to identify the effect of a superplasticizer based on polycarboxylic ether on the tribological behavior of fresh concrete at the concrete/formwork and concrete/oil/formwork interfaces. Friction tests on fresh concrete were carried out using a plan/plan tribometer. In order to study the behavior of the superplasticizer close to the formwork, three concretes with 30% of paste and different dosage of superplasticizer were formulated. The results show that the increase of the dosage of superplasticizer reduces the friction stress. The properties of the superplasticizer generate a deflocculating action of concrete grains and lead to a stabilisation of the soap-oil micellae present in the vicinity of the formwork. Thus, the efficiency of superplasticizer depends on the quantity of fines, on the quantity of soap formed and so, on the release agent formulation.

Keywords

Tribology; Concrete/Formwork Interface; Concrete/Oil/Formwork Interface; Superplasticizer; Release Agent; Physicochemical

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	C. Comparet, “Etude des Interactions Entre les Phases Modèles Représentatives d’un Ciment Portland et des Superplastifiants,” Thèse de Doctorat, Université de Bourgogne, Bourgogne, 2004.
[2]	C. Djelal, Y. Vanhove and A. Magnin, “Tribological Behaviour of Self-Compacting Concrete,” Cement and Concrete Research, Vol. 34, No. 5, 2004, pp. 821-828. doi:10.1016/j.cemconres.2003.09.013
[3]	Y. Vanhove, C. Djelal and A. Magnin, “A Device for Studying Fresh Concrete Friction,” Cement Concrete and Aggregates, Vol. 26, No. 2, 2004, pp. 35-41. doi:10.1520/CCA11897
[4]	C. Djelal, Y. Vanhove, D. Chambellan and P. Brisset, “Influence of the Application Method of Release Agents on Thickness of Mould Oils,” Materials & Structures, Vol. 43, No. 5, 2010, pp. 687-698. doi:10.1617/s11527-009-9521-z
[5]	S. Bethmont, “Mécanismes de Segregation dans les Bétons Autopla?ants (BAP)—Etude Expérimentale des Interactions Granulaires,” Thèse de Doctorat, Ecole Nationale des Ponts et Chaussées, Paris, 2008.
[6]	C. Djelal, P. De Caro, L. Libessart and I. Dubois, “Comprehension of Demoulding Mechanics at the Formwork/ Oil/Concrete Interface,” Materials & Structures, Vol. 41, No. 3, 2008, pp. 571-581. doi:10.1617/s11527-007-9268-3
[7]	P. De Caro, C. Djelal, L. Libessart, I. Dubois and N. Pebert, “Influence of the Nature of Demoulding Agent on the Properties Formwork/Concrete/Interface,” Magazine of Concrete Research, Vol. 59, No. 2, 2007, pp. 141-149. doi:10.1680/macr.2007.59.2.141