Performance Evaluation of Quarry Dust Treated Expansive Clay for Road Foundations

Expansive soils can cause significant distress in pavement construction because of their swelling and shrinking nature. One such method to control this problem is addition of stabilising agent to the expansive soil. Millions of tonnes of quarry dust waste produced every year are not disposed properly, resulting in environmental pollution as well as serious health hazards. Hence, an experimental study including scanning electron microscope (SEM) analysis was taken up for possible replacement of quarry dust in the expansive clay solving a dual problem. The quarry dust percentage in expansive clay was varied from 10 to 25%. The laboratory tests were conducted to ascertain the index properties, compaction and swelling characteristics and cohesion properties of expansive clay–quarry dust mixes. The unconfined compressive strength as well as the maximum dry density increases up to 85% soil + 15% quarry dust proportion. Hence, the optimum dosage of the quarry dust is found to be 15%. The swell potential decreases from 14.73 to 7.17% at the optimum dosage. The performance evaluation for the use of quarry dust waste in subgrade stabilisation based on group index (GI) method has been discussed in this paper. From the cost analysis, it has been confirmed that there is a substantial savings in the cost of flexible pavement construction when the quarry dust stabilised expansive clay is used as a subgrade in place of expansive clay.