Based on comparison of technical and economic parameters of the structure versions, the design institute Dorproject OAO and the road construction company VAD ZAO’s design department specified installation of a protection and reinforcement interlayer of Geospan GT PP 40 woven geotextile, rather than an imported geogrid, at the interface of sand and macadam layers of the road pavement structure. The proposed road pavement structure (5+6+10 cm of asphaltic concrete, 40 cm of base macadam and sand mix with grain size of up to 4 cm, Geospan GT PP 40 protection and reinforcement interlayer, 40 cm of mid-sized sand sub-base, subgrade of fine sand) was found to meet RIN 218.046-0 criteria at the accepted design data, which was confirmed by the road pavement calculations performed with the woven geotextile armoring influence taken into account. The comparative calculations of the road pavement versions were made in CREDO RADON program.
The feasibility of Geospan GT PP 40 reinforcement and separation interlayer at the interface of the lower base of macadam and sand mix and the sand sub-base, as compared to an imported geogrid, was confirmed by the federal agency ROSDORNII’s verdict No. 01-14/0366 dated 10.10.2013 driven by the following factors:
- high dynamic loads on heavy-traffic roads necessitating reinforcement of road pavement to increase shear resistance, i.e. deceleration of residual deformation accumulation, that would bring about an increase in a road structure operability and service life;
- compliance of the geomaterial properties with GOST R 56338-2015 requirements and Company Standard 34.13330.2012 recommendations, in particular with regard to the strength required for roads of category I -II i.e. at least 40 kN/m (Table D.2);
- availability of the Federal Road Agency’s approval of the Company Standard and 3rd party laboratory test reports.
The civil works at this section were executed by VAD ZAO during 2014 to 2016.
