Determination of glass content in fly ashes and blast-furnace slags

Abstract

In North America, there is an increased interest in the pozzolanic and cementitious properties of mineral wastes and in the potential for using these wastes as partial portland-cement replacement in concrete, either in the form of blended cement or as mineral admixtures at the mixer. Most waste materials are reactive when in a glassy state. A general theory, common to all these by-products, should explain the behaviour of glassy materials incorporated in portland cement in concrete. The purpose of this study was to find an accurate procedure to measure glass content in mineral wastes in order to predict their behaviour in concrete for offshore construction. A number of methods were used for measuring glass content in nine fly ashes and two blast furnace slags. The methodologies for two X-ray diffraction techniques were developed in this study. These two techniques are applicable to all classes of glassy waste materials. On the other hand, the quantitative X-ray diffraction method to evaluate the glass content of a material with a number of uncommon crystalline phases may be a very time-consuming technique. The non-crystalline X-ray diffraction approach cannot be used for materials which cannot be vitrified through rapid quenching.

Hydration and strength development in blended cement with ultrafine granulated copper slag

“…This will consequently accelerate the early hydration process of cement. The UGCS studied here with BET surface area of 1.31 m 2 /g is much finer particle size than that reported in other investigations with the fineness between 0.3–0.7 m 2 /g [8,22,23], which increases the surface available for pozzolanic reaction between UGCS particles and CH.…”

“…Their studies show that the ultrafine materials exhibit higher reactivity, and the compressive strength development of blended cement pastes is mainly dependent on the fineness instead of milling duration. Previous studies investigating utilization of copper slag in cement and concrete focus on the materials with fineness ranging from 0.3–0.7 m 2 /g [8,22,23], which is a big obstacle to its wide application.…”

Application of differential thermal analysis to determine the influence of the thermal history on the degree of vitrification in the system CaO-MgO-SiO2

“…No exotherm was observed for well-crystallized samples. The reactivity with water was assigned to the glass content.The glass content of a slag, an important factor determining its hydraulic properties [1], can be determined by X-ray diffraction [2,3] or by scanning electron microscopy [4]. The properties of slags also depend on the fineness and the cooling rate [5].…”