The latest research by the US Corps of Engineers has shown aggregate layers stabilised with TriAx deliver significant performance benefits to ﬂexible road pavements, reducing surface rutting by up to 44%.
Researchers confirmed that “incorporation of a multi-axial geogrid in a ﬂexible pavement base course provides a significant structural benefit”.Results also demonstrated that incorporating TriAx could cut construction time and costs by up to 19% and reduce carbon emissions by a quarter, compared with a thicker, non-stabilised pavement.
The full-scale accelerated pavement testing compared the performance of three pavement sections: a control of 100mm of asphalt and 200mm of crushed limestone and two sections of 75mm of asphalt and 150mm of aggregate, one incorporating a single layer of TriAx TX5 and the other a layer of TriAx TX8. The underlying subgrade was a ‘competent’ clay with a CBR of 6%.
The pavement sections were subjected to more than 800,000 Equivalent Standard Axle Loads (ESALs), the same tracking load that would be imposed by 690 million cars passing over them.
Rut depth was measured throughout testing. Sections incorporating TriAx performed significantly better than the control, despite being more than 25% thinner. Total surface rutting in the non-stabilised control section was 16mm, while rutting in the TX5 and TX8 stabilised sections was just 8mm and 7mm respectively. All of the deformation was in the asphalt layer, demonstrating that the geogrid stabilisation eﬀect provided additional support and protected the subgrade.
“Incorporation of a multi-axial geogrid in a ﬂexible pavement base course provides a significant structural benefit.” US Corps of Engineers.