Evaluation of flowability of cementitious self-leveling pastes by varying the superplasticizer and viscosity modifying admixture

Avaliação da trabalhabilidade de pastas cimentícias autonivelantes através da variação do teor dos aditivos superplastificante e modificador de viscosidade

Abstract

To meet the self-leveling pastes’ performance requirements, its flowability is linked to the absence of segregation or exudation, which makes a high cohesion between the components mandatory. Therefore, the ideal dosage for these materials is an essential topic to provide such specific properties. To evaluate the composition effect on fresh state, a method was proposed to quantify self-leveling pastes’ uniformity through the analysis of the spread pastes’ diameter and borders. Thus, different dosages were tested varying some input contents. The uniformity was quantified with the development of indexes such as Perimeter Ratio (PR) and Input Relation (IR). It was concluded that lower spread diameters incurred in higher uniformity index. Furthermore, it was observed that to achieve an ideal dosage for pastes, there is a tendency of direct correlation between the uniformity index and the water/powder ratio (w/p) and superplasticizer (SP) content and an inverse one between it and viscosity modifying admixture (VMA).

Keywords:
self-leveling pastes; cementitious paste; dosage; pastes’ uniformity index