Full scaled-column blast experiments for investigating the influence of the stemming materials on the column fragmentation in explosive demolition

Explosive demolition of structures may cause blowouts, flying rocks, and noise due to shorter length of drilling and stemming, compared to rock blasting. Therefore, stemming plays a very important role in this process, but there have been few studies on the effect of types of stemming materials on blasting efficiency. The study analyzed explosion confinement of selected three stemming materials; natural sand + crushed stone mixture, non-shrinking grout mortar and white cement mortar, applicable to explosive demolition through single hole blast tests of rectangular and square type columns. It was revealed that non-shrinking grout mortar was highest in blast efficiency and stemming resistance performance in rectangular type columns. Three stemming materials should be applicable to explosive demolition of square type columns which have relatively long stemming length.