evaluation of recycled materials as aggregate of end bearing and floating stone columns: a comparative study

The object of this research is to compare the behavior of floating and end bearing stone columns made of recycled aggregates of building debris with natural aggregate. to do so, both types of stone columns were constructed by crushed concrete and crushed brick as recycled aggregates and compared with the same models made of gravel as natural aggregates. all the columns were constructed with the same size, density, and grading in a clay bed. to evaluate the initial quality of materials of the stone columns, the index tests including aggregate impact value test and aggregate crushing value test were performed. the results of such tests illustrated the less resistance of recycled materials in comparison to the natural materials; on the contrary, according to the results of the index tests, crushed bricks are not recommended to construct stone columns. despite the index tests, results of loading on a floating column filed with natural and recycled aggregate were approximately the same, approximately five times the unreinforced bed, while the bearing capacity of the end bearing column made of natural aggregates was 35% more than the same model made of recycled aggregates.