EVALUATION OF BY-PASS DUST FOR THE PRODUCTION OF BLENDED CEMENT­ CONTAINING BLAST-FURNACE SLAG

Abstract

The present study was mainly directed to the possibility of utilization of . cement kiln dust in the production of building materials. Cement kiln dust IS accumulated tn relatively big quantities during the manufacture of portland cement clinke.r by the dry-process in Egypt. The accum­ ul•ation of kiln dust within the area of cement industries and its spreading in the surrounding atmosphere represent a bi•g environmental problem of pollution. A !so granulated blast-furnace slag, the by-product of iron and steel industry, was used as a starting material.

Two hydration reaction were studied these at:e: (i) un­ washed cement kiln dust-slag hydration reaction and (ii) washed cement kiln dust-slag hydration reaction. Six cement kiln dust/slag mixes were prepared in the weight ratios I 0/90, 20/80, 25175, 30170 40/60 a.nd 60/40; the pastes were made . using a water/soild ratios of 0.30. The hydrated specimens of each Mix were cured for 0.083, 0.25, 1, 3, 7, 14, 28 and 90 days.

At the end of each hydration period the specimens were tested for compresstve strength, hydration kinetics and X­ ray diffraction analysis. Hydration kinetics were studied by determining combined (non-evaporable) water, free lime and free slag contents at the various ages of hydration .