Effect of molecular weight of sulfanilic acid-phenol-formaldehyde condensate on the properties of cementitious system

The effect of the molecular weight of sulfanilic acid-phenol-formaldehyde condensate (SPF) on the properties of cementitious system was investigated. It is found that SPF with the molecular weight of 35,000 Dalton (Da) gives a good adsorption capacity on the surface of the cement particles, hence a larger zeta potential to cement particles and a good fluidity to the cement paste. In addition, this fraction has a high chelating capacity to calcium in the cement slurry, causing a long retardation of the cementitious system. However, the fractions of a high molecular weight (42,000 Da, and 45,000 Da) exhibit lower bleed water as a percentage of total mix water (BWP). It can be deduced that there is an ideal molecular weight for the best performances of the superplasticizer investigated, which can be used for optimizing the technical parameters in the preparation.