Quality analysis/quality control tests for field stabilization/solidification — 1. Dry cementing additives

As part of a field validation study of their proposed protocol for solidified waste evaluation, which will correlate laboratory test results with field behaviour, the Wastewater Technology Centre investigated the applicability of several rapid tests for quality analysis and control of the field solidified waste. A pilot-scale landfill was constructed and 63 m3 solidified arc furnace dust placed in it using a cementing system consisting of blast furnace slag, lime, silica fume and sodium metasilicate. The ground blast furnace slag, hydrated high calcium lime and silica fume were pre-blended before being trucked to the field site and the sodium metasilicate was added in the mixing water. Available lime index using the rapid sugar method (ASTM C-25) and measurement of specific gravity were used to determine the effect of mixing procedures and transportation on the homogeneity of the blended dry additives. Experimental results indicate that the rapid sugar method can give an accurate analysis of lime content in the pre-blended additives. There is a good linear relationship between the slag content and specific gravity because the lime and silica fume have a similar specific gravity. However, the agglomeration of the blended additives affects the accuracy and precision of the method.