Model Tests of Recycled Aggregate Use in Rammed Stone Columns

Construction activities are generating substantial amounts of construction waste due to the rapid increase in economic growth and infrastructure developments. A series of laboratory model tests were conducted to investigate the feasibility of using recycled aggregate as backfills to construct the rammed stone columns. Recycled aggregates and gravel aggregates with the same particle size distributions were used to construct the rammed stone columns. The direct shear test results showed that the recycled aggregate exhibits similar behavior of initial compression but more significant expansion compared to those of the gravel aggregate. The critical bearing capacity of the rammed stone column using recycled aggregate as backfills was 6.2%–6.5% lower than that using the gravel aggregate as backfill, but was 36.1% higher than that of the traditional stone column. The rammed stone column was failed in bulging failure mode with the maximum bulging position of approximately 2d from the column head. The critical bearing capacity of the rammed stone columns could be estimated according to that of the traditional stone column by considering the effects of the tamping energy.