phosphate ores and quarrying operations of marble and granite rocks. These wastes are stored in
piles around or near mine sites, which are aesthetically unattractive and often degrading the
environment. Various solutions have been sought for this major environmental problem and the best
solution found is recycling. However, these wastes , because of their similarity to the conventional
aggregates , represent a potentially useful source of material for a variety of applications ( in
roadbed and dam construction , as railroad ballast ,as aggregate in concrete and asphalt mixes , …)
The main purpose of this research is to investigate the possibility of utilizing the above mentioned
three waste materials in road construction (base and sub base) and as a replacement layers for the
problematic soil in foundations. Experimental tests were carried out on these wastes to assess their
physical, mechanical and chemical properties, according to the Egyptian standards. The modified
proctor and California bearing ratio (CBR) are the most important tests of soil compaction to assess
the suitability of any waste materials. The CBR value of phosphate waste is 88% , 95% for crushed
marble and about 41% for crushed granite. The obtained results proved that these kinds of wastes
can be used in base and sub-base layers in road construction and as replacement soil under
foundations. The potential uses of these wastes are considered beneficial from the economic and
environmental points of view and saving the natural resources of aggregate.