After decades of service, the surface of Caka Street in Riga, Latvia, was in very poor condition. The Transport Department of the City Council decided to renew a length of approximately 2.5 km. It was only possible to add a thin asphalt overlay. The challenge was to maximise the life of the new surface.  

The overlay design incorporated Tensar AX5-GN asphalt interlayer. Approximately 35,000m2 of the reinforcing product was installed to control cracking and increase fatigue life. Tensar AX5-GN is a composite asphalt interlayer consisting of a stiff polypropylene grid with hexagonal structure and integral junctions bonded to a polypropylene paving fabric. The geogrid performs the structural reinforcement function [R] of the asphalt interlayer, whilst the non-woven, fully saturated with bitumen, functions as a stress relief system (STR) and an interlayer barrier (IB).