Modelling of chemical and morphological changes of silicate fibres used in a Portland cement matrix

Abstract

Basalt and glass wool materials were continuously eluated in saturated lime water and in 10^3 mol NaOH/m3 at 70 °C. The alkali resistance of fibres was investigated, in particular its dependence on the chemical composition of the fibres and on the nature of the reaction products formed on the fibre surface. For this purpose wet chemical and x-ray diffraction analysis, as well as scanning electron microscope and microprobe were employed. The higher alkali resistance of basalt fibres against both corrosive agents can be explained by their higher MgO and Fe2O3 as well as lower Na2 and K2O contents.