Bio-Enzymatic Stabilization of a Soil Having Poor Engineering Properties

Soils with poor engineering properties have been a concern to construction engineers because of the need to strike a balance between safety and economy during earthworks construction. this research work investigates the effects of treating a soil having poor geotechnical properties with a bio-enzyme to determine its suitability for use as road pavement layer material. the elemental composition and microstructure of the soil was determined using energy dispersive x-ray spectroscopy and scanning electron microscopy,respectively. the specific gravity,atterberg limits,compaction,strength and permeability characteristics of the soil was determined for various dosages of the bio-enzyme. the mountain soil is classified as clayey sand and a-2–4,according to unified soil classification and aashto classification systems,respectively. with increasing dosage of the bio-enzyme,the plasticity index,maximum dry unit weight and permeability of the soil decreased,while its 28-day california bearing ratio value,unconfined compressive strength and shear strength increased. consequently,the application of bio-enzyme to the soil improved its plasticity and strength,and reduced its permeability. it,therefore,became more workable and its subgrade quality was improved for use as a road pavement layer material. the stabilized soil can be suitably used for constructing pavement layers of light-trafficked rural (earth) roads,pedestrian walkways and bicycle tracks. © 2016,iran university of science and technology.