Consumption of superplasticizer admixture for different cements and their binder efficiency

Abstract

ResumoThe optimum content of ether polycarboxylate-based superplasticizer, determined by rotational rheometry, and its effects on the environmental impacts of concretes were studied for cement and limestone filler. To assess the consistency and water reduction, flow-table tests were performed. Then, cement content reduction and binder and carbon intensity indexes were determined through estimation based on theoretical concretes. The evaluated pure and blended cements present significant variability of the optimum consumption of the admixture. The fillers consumed less superplasticizer per area than the other materials and compositions with fillers allowed for greater reduction of water content. The mixtures with superplasticizer presented lower cement rate and binder and carbon intensity indexes. The usage of this type of admixture in optimal content can reduce environment impacts, according to the parameters analyzed.Keywords: superplasticizer, ether polycarboxylate, cement, binder efficiency, environment impacts.Foram estudados, em cimentos e fillers calcários, os teores ótimos de superplastificante (base policarboxilato éter), determinados através de reometria rotacional, e estimados seus efeitos nos impactos ambientais de concretos. Ensaios de espalhamento de argamassas em mesa de consistência foram feitos para determinação da redução de água e estimação de redução do cimento e intensidades de ligantes (IL) e CO 2 (IC) em concretos teóricos. Os cimentos estudados apresentaram significante variação de consumo de superplastificante. Os fillers consumiram menos aditivo por unidade de área do que os demais materiais e suas composições apresentaram maior redução de água. O uso de superplastificantes levou à redução do consumo de cimento e das intensidades de ligante e carbono. A otimização do teor de superplastificante se mostrou eficiente para a redução de impactos ambientais.Palavras-chave: superplastificante, policarboxilato éter, cimento, eficiência, impacto ambiental.

Development of lignin-based polycarboxylates as a plasticizer for cement paste via peracetic acid oxidation

“…The former contains few carboxyl group to be adsorbed on cement surface, and the latter cause steric hindrance which is the main mechanism to increase cement fluidity for PCE. However, it is expensive to use for this purpose (Cecel et al 2019), and it would be beneficial to replace this expensive plasticizer.…”