New Super-plasticizers Based on Modified Melamine Polymer

Admixtures based on sulfonate melamine formaldehyde condensate polymer (SM) have been available commercially for more than three decades. These products are widely used by the precast concrete industry, but with some limitations on slump retention and early strength. To improve these properties, synthesis of a modified sulfonate melamine formaldehyde condensate polymer (MSM) was performed. In this paper its physical and chemical characteristics are reported. Dispersibility and adsorption tests, using cement pastes, were carried out to compare the superplasticizing effect of the new MSM polymer against the SM polymer. Concrete mixtures were also made to evaluate the performances of this MSM polymer in comparison with the other types of superplasticizers such as SM and beta-naphthalene sulfonate formaldehyde condensate (SN). Results of these tests show that MSM polymer has a better water reduction capacity, lower air content in the fresh concrete and higher early strength at 1 day as compared to the other superplasticizers under the test conditions. These characteristics are very much desired by the precast industry for easy placement of concrete and quick turn around of the formworks. Field tests also reported, confirm the laboratory findings.