Mankind has always craved for sophistication in order to minimize its effort and maximize outcomes. In the field of transport, man first invented wheel after which transport of materials became easier. With more need to move materials from one place to another swiftly, the steam and petrol engine was invented as next versions of sophistication in the field of transport.
The same approaches were made for other fields like engineering, medical sciences, defence, administration, communication and so on. Being a student of Geo-Technical engineering, I will focus on the recent developments and innovations in the field with respect to its scope here in Kashmir valley. Kashmir region has extreme weather conditions ranging from the average temperature of 38ºC in summers to -7ºC in winters with mild to heavy precipitation almost throughout the year. For soil, variation in temperature plays an important role in strength of the same. Freezing and thawing process, frost heave in winters further make it worse as far as the stability of the roads in winters is concerned. As per various researches done on the soil of this part of sub continent, poor drainage, high water table and weak sub-grade are the main contributing factors for the early failure of the roads which in turn incur heavy losses to the state exchequer every year on account of maintenance cost of roads. Without getting to actual cause of pavement failure, patch work, resurfacing and other repair work is done only after 1-2 years of the pavement construction though the average lifespan of Flexible pavement is 7-10 years.
Loading due to vehicles tend to push the sub-base material (coarse aggregates) into weak sub-grade (soil) thus reflecting potholes at the pavement surface and secondly upward movement of water at the time of high water table further decrease the subsequent bearing capacity of the pavement layers especially sub-grade. Also , the capillary water expands in the sub-zero weather conditions thus disintegrating the pavement materials.
We don’t have any control on the temperature variations but the adoption of various methods which can reduce the allied ill-effects of these thermal variations and capillary actions of water are definitely at our disposal. One such great innovation is the use of textile fibres (woven and non-woven) in the soil for engineering purposes. For the sake of its purpose in the soil, these are called “Geo-textiles”.
These can be natural as well as synthetic material. Modern Geo-textiles are usually made from synthetic polymers, polypropylene, polyesters, polyethylenes and polymides which don’t decay under biological and chemical processes. Natural Geo-textiles can also be made resistant to biological decay by applying epoxy-resin. They have high tensile strength, mechanical damage resistance, acid and aggressive biological environment resistance. They are also not water-soluble thus don’t release toxic chemical upon having contact with water.
Geo-textiles have many uses. They act as:
(1) reinforcing material,
(2) filter that allows only the water molecules to pass through, and
Geo-textiles are widely used in civil and road construction, oil-gas area, for domestic needs, melioration and landscape architecture. These can have a promising use in the pavement construct here in the region of Kashmir as all the pre-requisites for which it was introduced are available here. In sheets (Geo-grids) between sub-base and sub-grade layer, it acts as a tough separator and don’t allow the sub-base material protrude into weak and soft sub-grade, thus reducing the pothole formation which is a common failure of pavements in the valley. Also, when the high water table is high, the fibres pave way for the water molecules that are brought up due to capillary action to move out laterally through the Geo-textile membrane and drain to a suitably provided space without affecting the sensitive wearing surface of the pavement.
Moreover, Geo-textiles are easy to use, no heavy machinery and skill is required to lay Geo-textiles in the soil or pavement layers. Their use can be an efficient and economical modification in the design of modern-day road pavements in a region like Kashmir.
The Roads and Buildings (R&B) Department having a full-fledged Geo-Technical engineering Lab in Kashmir should introduce this innovation in the pavement construction at least on trial basis after proper soil testing and design. If feasible this new technique can save a lot to the state exchequer and also the precious time of the engineering department that it can be invest for those projects that are of utter importance for the general public.
The Author is studying Geo-Technical Engineering from Kurukshetra University. He can be reached at: email@example.com