Influence of the workability on adhesive properties of polymer-modified mortars used for repair
Résumé
PMMs (Polymer-modified mortars) are increasingly used to repair works. Addition of polymers in these mortars does not only change their final properties but also modifies their workability. This article deals with the relation between adherence of PMMs on concrete surfaces and their rheological properties. SA and EVA powders-modified mortars have been formulated with the same consistence. Mini-cone slump tests show that to obtain the same consistence, the increase of polymer amount lowers the water requirement. So, workability is enhanced with adding polymer. However,the spreading process observed on different PMMs shows the opposite. Indeed, low polymer-amount-PMMs spread due to mixing water effect. By the other side, high polymer-amount-PMMs slump under their own weight and their flow is lower. Therefore, during a repair, low polymer-amount-PMMs are easily spread on the repaired surface, which promote a good adhesion, while high polymer-amount-PMMs have less contact with repaired surface, which results in a low adherence.