PAVEMENT REINFORCEMENT USING GEOGRID MATERIALS

Abstract

Pavement crust thickness and its construction cost depend upon the strength of subgrade-scil. Number of techniques' are availablete improVe the load carrying capacity of the subgrade-soil. However, today there is the need of energy saving, cost saving and time saving techniques and material systems. The reasons for the sudden development of composite structures'are the recent accelerating develop-ment of technical expertise and material systems in eogineering. The synthesis of strong, non-degradable polymer geosynthetics and in particular open meshes (geogrids) has permitted the inclusion of these materials in long term civil engineering structures and in particular for the reinforcing of flexible type of highway and airfield pavements. • Compared to the, geotextiles, geogrid materials are having open mush structureslhigh strength, rigidity and durability and they derive their strength from the better interlocking mechanism. These are having high tensile strength, non-corressiveness, temperature resistance, biolo-gical resistance and resistance to •ultra-violet rays, etc.11 Those can act as separators, filters or reinforcing elements and display exceptional properties which results into the financial saving, increased efficiency and bettor performance. When used in pavements they reduce fatigue cracking, reduce amount of ruts and thickness requirements of various courses+ In the present study attempts have boon made to review the work done on the use of goosynthetics and in particular to describe the geogrid types, properties, mechanism and functions pavement construction. Experimen-al work like CBR tests, Fatigue tosts,Plste Load tests and Large Shear box tests have been carried out using Notion CE-121 type googrid to observe its functional and structural behaviour as a pavement material. it has been found that the subgrade CBR improves considerably, pavement can take more number or load cycles and pavement thickness can be reduced. Design charts have boon developed and the constru-ction procedure has boon described along with the advantages of these modern revolutionary materials. Economic analysis shows that under present situation intial capital cost will be slighty more. However, in long term geogrid materials will prove —to be economical compared to the conventional pavement materials and we may not have er to think of cement concrete pavements as on altfnate to flexible pavements due to heavy axle load. It has been recommended that the vast potentials offered by these materi-als should be fully exploited for the construction of stronger, durable, economical and almost maintenance free pavement structures. (iv)