Influence of hydroxypropylguars on rheological behavior of cement-based mortars

Thomas Poinot (1, 2, 3) , Alexandre Govin (1, 2, 3) , Philippe Grosseau (1, 2, 3)

1 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
2 LGF-ENSMSE - Laboratoire Georges Friedel
3 PROPICE-ENSMSE - Département PROcédés Poudres, Interfaces, Cristallisation et Ecoulements

Hydroxypropylguars (HPGs) are used as water retention agents in modern factory-made mortars. Nevertheless, these molecules can also impact the rheological behavior of cement-based materials. The influence of HPG and its dosage on mortar rheological properties was thus investigated thanks to a suitable measurement procedure. HPG allows keeping a positive yield stress value while the yield stress of hydroxypropyl methyl cellulose (HPMC) mortars was found to decrease with an increase in dosage. HPG increases the shear-thinning behavior and the consistency of mortars. The study of pore solution viscosity suggests that the entanglement of HPG coils beyond a threshold dosage is crucial to understand the rheological macroscopic behavior of HPG-admixed mortars. Nevertheless, the increase in mortar viscosity induced by HPG was lower than expected which reveals additional and specific repulsive forces induced by polysaccharides.

Mots clés: Polysaccharide; Hydroxypropylguar; Admixture; Mortar; Rheology

Domaines: Génie des procédés

Thomas Poinot, Alexandre Govin, Philippe Grosseau. Influence of hydroxypropylguars on rheological behavior of cement-based mortars. Cement and Concrete Research, 2014, 58, pp.161-168. ⟨10.1016/j.cemconres.2014.01.020⟩. ⟨hal-01056877⟩