Istanbul Teknik Brings Its Innovative Understanding to Highway Superstructure
Istanbul Teknik; aims to use its production power at international standards in geogrid production to reduce road superstructure maintenance costs in Turkey and extend the project life of roads.
The most important part of the transportation sector in Turkey is highways. According to the Highways ‘State and Provincial Roads Inventory’, Turkey has a total of 68,231 km of highway network, including 3,060 km of highways, 31,006 km of state roads and 34,165 km of provincial roads; 56% of Turkey consists of surface-coated roads, 37% of asphalt concrete roads and 5% of other roads. Naturally, the road superstructure constructions that require maintenance, repair or reconstruction of a road network at this level constitute a serious share in the state budget.
Geogrids are used as concrete reinforcement in reinforced walls thanks to their high tensile strength and long life, and in ground improvement to reduce differential settlements that will occur in the ground and increase bearing capacity. Both types of geogrids, glass fiber woven and polyester woven, are used for many purposes, primarily for ground improvement, reducing the thickness of asphalt concrete layers or increasing the durability of layers. The cases where glass fiber grid, which is widely used in the geogrid sector, exhibits lower performance than expected due to difficulties in application and logistics have been mostly ignored.
However; polyester geogrids; can be more economical than glass fiber woven geogrids that perform for similar purposes if the application conditions and technical requirements specified in the Highways Technical Specification (2013) are met. Glass fiber grains, which have a very fragile structure, undergo deformation if they are not well protected in each of the transportation, handling and application stages. Situations where the deformation tolerance limits calculated for the projects cannot be met for these reasons can be turned into more efficient applications with polyester woven geogrids.
With the project “Using Polyester Geogrid in Asphalt Layers” carried out at Istanbul Technical Construction R&D Center, since polyester geogrid has not been applied in asphalt superstructure layers in Turkey yet, its unknown effects on friction, shear strength, bending strength, stability, superstructure cracks and settlement will be determined, and its benefits on construction costs will also be proven thanks to this study and these results will contribute to the sector.
As a result of the studies carried out for this project carried out with the new type of polyester geogrid developed by Istanbul Technical Construction R&D Center, the behavior of the polyester woven geogrid element between asphalt layers under cyclic loads will be determined, and the level of improvement and efficiency that its use in road superstructure will provide will be determined.
The results obtained so far in the studies carried out with Eskişehir Technical University within the scope of University-Industry Cooperation have shown that polyester geogrid provides significant differences in logistics, application and cost compared to glass fiber woven geogrid. It has been observed that it increases the superstructure strength, and despite the reduction of the thickness of the abrasion and binder layers forming the asphalt concrete superstructure, it can meet higher traffic loads thanks to the polyester woven geogrid used between the layers. In this way, profit can be made from asphalt layers made with large budgets.
In addition, it has been observed that the formation of reflection cracks formed on the ground and transmitted to the upper layers is reduced with the use of polyester geogrid between asphalt layers. All these results will reduce the road maintenance costs made with large budgets and provide great profitability and high efficiency.
With this ongoing project, Istanbul Teknik İnşaat has signed another first and added new values to its innovative and life-facilitating policy in the sector.
