Blending of acrylic superplasticizer with napthalene, melamine or lignosulfoate-based polymers

Acrylic polymer (AP) performs better than other superplasticizers based on sulfonated-naphthalene-formaldehyde (SNF), sulfonated-melamine formaldehyde (SMF) or modified lignosulfonate (MLS). It is better than the other superplasticizers in terms of higher initial slump, at equal water-cement ratio (w/c), and lower rate of slump loss. AP, however, is a little more expensive than SMF and much more expensive than either NSF or MLS. Therefore, blending of AP with the other polymers could reduce the cost. The purpose of the present work was to study the influence of binary blended admixture (AP on one hand, and SNF, MSF or MLS on the other one) on the performance of superplasticized concretes in terms of slump, slump loss, specific gravity, air content and compressive strength at equal w/c. The data presented in this paper indicates that there is no practical advantage in blending AP with NSF or MSF. Moreover the combination of AP with NSF seems to be unreliable because produces an erratic reduction in the workability of the concrete mixture when about 75% of AP is replaced by NSF. On the other hand, a combination of AP with MLS appears to perform as well as the pure acrylic polymer in terms of workability, slump loss, air content and strength development, provided that the replacement of AP by MLS is not higher than 25%. Therefore, these blended AP-MLS superplasticizers appear to be very interesting because they are cheaper than the pure acrylic polymer at approximately equal performance.