To increase the workability of concrete, aqueous solutions of superplasticizers are added to cementitious mixtures. The strength of concrete is inversely proportional to water content that is used in the mixing process. Superplasticizers are used to lower the water to cement ratio, while keeping necessary fluidity, to make high performance concrete. Although conventional superplasticizers (e.g. melamine and naphthalene based polycondensates) reduced the amount of water needed for workable mixtures, their ability to retain flow over time is limited. The new generation of superplasticizers (i.e. polycarboxylate ether-based superplasticizers (PCEs)) exhibit superior dispersing ability compared to the conventional superplasticizers due to their special chemical and structural properties. PCEs have ionizable groups in the backbone to adsorb to the surface of cement particles and also contain side chains (i.e. poly(ethylene oxide)) that protrude from the cement surface into the pore solution to produce steric hindrance effect.
This technology provides high performance modified PCEs without using any chain transfer agent and a complex initiator system. Molecular weight of the polymer is controlled by pre-adjustment of pH level of the polymerization medium. Since the pH level of the final product is approximately 7 – 8, a neutralizing step at the end of the process is eliminated. Initial reaction medium contains all the monomers such that the step of the gradual addition of monomers throughout the reaction is eliminated and also addition of the initiator is limited to two parts; at the beginning and in the middle of the reaction.
Cement is considered as one of the key enablers for modern construction and concrete is used as an essential material for all types of construction. That's why, this novel technology can be used in different fields as indicated below because it creates higher fluidity and slump retention compared to commercially available superplasticizers. Superplasticizer for different types of cement Dispersing agents for the processing of ceramics
This modified superplasticizer exhibits higher fluidity and slump retention compared to commercially available superplasticizers and remains effective in medium with high concentration of sulfate ions. This technology also provides a simple cost effective and environmentally friendly production method of such additive.