BLOATING CHARACTERISTICS OF LOW GRADE Ca-MONTMORILLONITE CLAYSTONE AND THE EFFECT OF SOME ADDITIVES

Abstract

This study was conducted to assess the bloating characteristics of the calcium montmorillonite claystone from Wadi Bashira in the Iraqi Western Desert and indicate the effect of red kaolinitic claystone and feldspathic sand addition. The materials were formed into pellets, (aggregates) after mixing in different wt% combinations. The results of heat treatment of aggregates formed only from montmorillonite claystone indicated that, bloating incidence occurs at a temperature of (1180 – 1200º C). The bloated aggregates obtained exhibit a considerable low bulk density (1.185) g/cm3¬ and low mechanical strength. All aggregates made from the mixtures (montmorillonite claystone, red kaolinitic claystone with, or without feldspathic sand) showed a good to very good bloating. Also the aggregates made of montmorillonite claystone and feldspathic sand (except that made with 5 wt% feldspathic sand) showed a good bloating. The bulk density of the bloated aggregates obtained was appreciably low (0.54 – 0.7 g/cm3) with water absorption value of (4 – 6.8) %. This suggested that these aggregates can probably used, as lightweight materials in civil works.