Influence of geosynthetic reinforcement on unpaved roads based on CBR, and static and dynamic cone penetration tests
International Journal of Geosynthetics and Ground Engineering
School of Engineering
Dynamic cone penetrometer has been used widely as a pavement evaluation technique for many years. Unpaved roads constructed on weak soil subgrade are frequently subjected to severe damage and hence, they require regular maintenance and repair. One of the main stabilization methods of improvement of the serviceability of these roads is to reinforce them with geosynthetics (geotextile/geogrid). Field experiments were conducted on unpaved test sections reinforced with geotextile and geogrid, with the potential use of dynamic cone penetrometer (DCP) and digital static cone penetrometer (SCP) to assess benefits of geotextile and geogrid reinforcement. Laboratory California bearing ratio (CBR) tests were also conducted on subgrade–aggregate section and the effect of geosynthetic reinforcement was investigated by placing the reinforcement layer at the interface of the base course layer and weak subgrade. Digital SCP was used to measure the load–displacement behavior of geosynthetic-reinforced test section in the field. The field test results of DCP were expressed in terms of dynamic cone penetration index (DCPI, mm/blow), defined as the penetration depth of the cone per hammer blow and recorded along with the depth profile. A decrease in DCPI value was observed for the reinforced test sections as compared to the unreinforced test section. DCP results were able to detect transition zone and significant change in the strength of unpaved test section along with penetration depth. The field results indicate the greater resistance to penetration in the geosynthetic-reinforced test section and the penetrometer resistance increases with the depth. Higher penetration resistance offered by the geotextile has more contribution to the performance improvement of the test section. © 2020, Springer Nature Switzerland AG.