Viabilidad de utilización de aditivo estabilizador de hidratación (AEH) para el reciclaje del hormigón en estado fresco: Estudio de caso en el sur de Brasil

Abstract

Residues generation at Ready-Mixed Concrete Plants (CPs) occurs due to concrete leavings in the drum mixer of concrete delivery trucks; waste in piping and pumps agitators; on truck's cleaning; and on the plant itself. The aim of this paper is to analyze technical and economic viability of employment of hydration control admixture (HCA) to permit reusing these residues. Technical viability was verified though setting times of samples with several HCA/cement ratios added to the concrete at the time of mixing, and also by setting times when HCA was added in time lag intervals of 1h and 3h after the admixture with a HCA/cement ratio of 0.30% by mass. There was verified axial compressive strength of the samples. Results showed that setting time increased progressively as long as it was increased rates of HCA. It was possible to reuse 88% of concrete leaving. Economic analysis permits to conclude that there are economic gains to the CPs. It can be concluded that hydration control admixture technique is an efficient way to recycle ready-mixed concrete residues.