Sorptivity, swelling, shrinkage, compression and durability of quarry dust treated soft soils for moisture bound pavement geotechnics

Abstract

The failure of pavement foundation materials as hydraulically bound materials is a worrisome condition facing pavement infrastructures in the developing world. Capillary action leads to swelling and shrinkage, compressive strength and durability problems, which result from sorptivity as a function of hydraulic exposure conditions. Pavement infrastructures a constantly interfaced with rise and fall of ground water level and capillary action hence a study on the sorptivity behaviour of quarry dust (QD) treated soft clay soils was carried out. Preliminary tests were conducted on the test materials for the purpose of characterization. The basic test results show that the test soils S1, S2 and S3 were classified as A-2-7, A-2-6 and A-7 soil groups respectively according to AASHTO classification system. Also, they were classified as poorly graded soils but test soils S1 and S2 were observed to be of high clay content (CH) according to USCS. The test soils were equally observed to be of highly plasticity and contains high free swell index properties, hence are expansive. Sorptivity, swelling, shrinkage, compressive strength and durabikity tests were conducted on the test soils treated with varying proportions of quarry dust in accordance with the appropriate standards. Tests results show that QD addition improved consistently the swelling potential, shrinkage limits, compression and durability of the treated test soils. While the improvement on the sorptivity were in two phases, a nick point divided the early age and late age of the sorptivity behaviour curves. However, QD has proven to be a good additive in the treatment of test soils used as pavement foundation materials in a moisture bound environment. Keywords: Sorptivity, Durability, Quarry dust, Moisture bound pavement foundation, Subgrade geotechnics, Recycled materials