Title:
The Effects of Polysaccharide Gum Additives on the Shotcrete Process
Author(s):
Virgilio A. Ghio and Paulo J. M. Monteiro
Publication:
Materials Journal
Volume:
95
Issue:
2
Appears on pages(s):
152-157
Keywords:
bond; polysaccharide gums; rheology; shotcrete;
DOI:
10.14359/360
Date:
3/1/1998
Abstract:
The rheology of fresh concrete can be modified by the addition of polysaccharide gums, which significantly increases the viscosity of the fresh concrete under low shear rates, although it has a reduced effect on the fresh concrete viscosity at higher shear rates. It has been found that this behavior can improve the shotcrete process because the relatively low viscosity of the fresh concrete under high shear rates generates an easy to pump and spray concrete. Moreover, the concrete will become cohesive and viscous after the shear has ceased, minimizing sag problems. The physical and mechanical effects of adding polysaccharide gums to fresh concrete were studied. It has been found that higher walls can be sprayed in one lift, lower pumping pressures can be obtained for similar slump values, and improved normalized bond strength can be obtained with the incorporation of the additive.