Concrete, hardened: Water-cement ratio (NT BUILD 361 – Edition 2)

Abstract

SCOPE

This NORDTEST method can be applied to estimate the water-cement ratio (W/C ratio) in hardened concrete, using microscopic investigation of thin sections. The method includes two impregnation techniques, vacuum impregnation with fluorescent epoxy and impregnation using the Fluorescent Liquid Replacement (FLR) technique. The latter technique supplements the epoxy impregnation at lower W/C-ratios. FLR technique is not applicable above W/C = 0.50.

FIELD OF APPLICATION

The method is applicable for well-hydrated Portland Cement concrete with or without admixtures such as plasticizers and air-void entraining agents. The degree of hydration of the tested concrete and the references should be of the same order. When fly ash, silica fume or slag are present, the “equivalent water-cement ratio” is estimated. It is not possible to estimate the W/C of Polymer Cement Concrete (PCC) or of coloured concrete.