A Laboratory Study on Compaction Behavior of Plastic Soils Mixed with Recycled Aggregates

The use of recycled aggregate in geotechnical engineering to enhance soil properties has received considerable attention in recent times. The use of recycled aggregate from demolition waste in conjunction with fine-grained soil is one of the most promising ways to recycle this waste material. The study has covered five different fine-grained base soil samples with a wide range of plasticity and addition rates of up to 50% of graded recycled aggregates (passing through a #4 ASTM sieve). Different geotechnical tests were carried out to evaluate the engineering properties of fine-grained soil samples mixed with different percentages (30% and 50%) of recycled aggregates. The optimum water content of the improved soils tends to decrease for soils with the addition of different percentages of recycled aggregate, and the change in the optimum water content (ΔOWC) is related to the addition rate. The maximum dry density increased for soils with the addition of recycled aggregate, and the change in the maximum dry density, ΔMDD, is also related to the addition rate. The improvement effect on soil is related to the liquid limit of soil as a high liquid limit reduces the improvement effect due to recycled aggregate addition. An increase in dry density with reduced water content of a soil can generally be equated to an increase in strength, lower permeability, and better volume stability.