Modification of Clay Using A-3 Soil

Abstract

Clay soil classified as A-7-6 according to AASHTO soil classification system and CH according to unified soil classification system was collected from Niger State Polytechnic Zungeru in Niger State. The clay was modified with A-3 soil sieved out from river sand. The clay was replaced with A-3 soil at 0, 10, 20, 30 to 100% by weight of the clay soil. Grain size analysis tests and Atterberg limit tests were carried out on each of the clay-A-3 soil mixtures to evaluate the effect of A-3 soil on the clay soil. Results showed that the liquid limit of the clay reduced from 59.3% at 0% A-3 soil replacement to 23.4% at 80% A-3 soil replacement. The plasticity index reduced from 32.5% at 0% A-3 soil replacement to 6.6% at 60% A-3 soil replacement. These represent 60% reduction in liquid limit and 80% reduction in plasticity index. A-3 soil is therefore an appropriate material for modification of clayey soils and 60% A-3 soil replacement is the maximum required for effective modification of clay soils.