DESIGN OF FLUID CONCRETE WITH SYNTHETIC ADDITIVES 4TH GENERATION (OR ESTERIC REPULSION)

Abstract

By definition, the self compacting concrete is recognized as a main characteristic is the capacity to flow and filling volume of poring concrete by the action of its own weight. The natural composition of the materials is the same for a conventional concrete (cement, aggregates, additions, additives and water). Its ability to be self compacting is due mainly to the high content in fines, to the low content in fine in thick granulometry and the high doses of additives. The present work tackles the research carried out on self-compacting concrete and the chemical additives used in its manufacture, specifically the so-called last generation or superplasticizers known as fourth generation additives or polycarboxylates. Differentiating theme, not depending on the brand or the manufacturer if not depending of their molecular structure, which it results to the creation of long chain additives or short chain additives. The key to obtaining a good HAC characterized by a high cohesion and with self-compacting properties lies in the correct optimization of the superplasticizer-additive combination (viscosity modifier). Therefore, the materials used have been the main part of the study to achieve the proposed objectives, guaranteeing the compatibility between them, the water/cement ratio and the achievement of established resistances stand out. The results obtained show the goodness of the 4th generation additives and show that the use of a correct granulometric curve together with the use of short chain or long chain additives gives us a significant variation in the strength of the concrete. Giving, sometimes, the option of dispensing with the use of different additions to obtain the improvement of results with the use of the additives tested. Keywords: concrete, self compacting, additives-4ª-generation.