CONSIDERACIÓN DEL AGUA EFECTIVA EN LA RELACIÓN AGUA/CEMENTO PARA LA FABRICACIÓN DE HORMIGÓN RECICLADO

Abstract

The manufacture of recycled concrete (RC) is not very widespread for structural purposes mainly due to the uncertainty that involve the use of recycled aggregates (RA). Their manufacture is often constrict in own techniques of conventional concrete (HC), without considering that it´s necessary to modify certain concepts in the dosage designs. Thereby, the specific water absorption and initial humidity of the RA suggests that water movements on the mix of concrete paste are different in relation HC.This experiment proposes to modify the use of the traditional concept of water to the concept of free or “effective water” and verify the effect on the water/cement (W/C) ratio. Thus, a method for calculating and estimating the water balance in the dosage are proposed, thereby concrete manufacture comparing total or effective W/C has been analysed. Also, governed by the water absorption speed, a mixing method based on the two-stage mixing method, with a dry pre-mix step and without saturation treatment of RA has been designed to let the industrial production. Results show the critical time to consider on the mix and demonstrate that an increase of total water does not result in a strength reduction provided that W/C effective kept constant.