Study of Sub Grade Soil Enhancers in Fatigue Behaviour

Abstract

A pavement structure can be designed either as a flexible pavement or a rigid pavement based on its structural behavior. In pavement structure the vertical or compressive stress are transferred to the lower layers by grain to grain transfer through the points of contact in the granular structure with strong graded aggregates and finally reaches to the sub grade. As the number of loads increases the stresses inducing in the pavement layers is also increasing, which intern causes the failure if the pavement layers. In this fatigue is one of the major problems in the pavement. Fatigue is a process of progressive and permanent material damage under repeated loading and it is estimated that 50-90% of structural failure is due to fatigue. Thus there is a need for quality fatigue design materials. The highway construction industry has made rapid studies in the field of new technology up gradation and adaption. With increasing traffic volume and an increased demand for innovative design, rehabilitation and repair of the aging transportation infrastructure. New materials and techniques have been tried with lot of emphasis on optimizing life cycle cost and minimizing design cost.

This project work mainly aims at studying the fatigue behavior of a soil specimen of 38mm diameter and 76mm height, under repeated loading. For this Universal Fatigue Testing Machine was used. Soils samples were collected along the NH67 which is sandy soil and a clay soil (black cotton soil) from MRF Tyre company near perambalur. The soil was stabilized with the RBI Grade 81 at different proportions namely 3%, 5% in case of sandy soils and 2%,3%,4%,5% in case of clayey soil. Various tested were conducted on the virgin soil and stabilized soil with RBI Grade 81 for finding index and engineering properties. The tests were conducted for different curing periods for finding the effect of age of curing on the soil.