Many researchers suggest using construction and demolition materials (C&D) in engineering applications rather than virgin aggregates (VA). However, the engineering properties of C&D tend to be poorer than those of VA. This study presents the results of plate loading tests performed on unpaved roads with C&D, reinforced by different types of geosynthetics on the soft subgrade. As part of these tests, the effects of some geosynthetic parameters such as (a) the embedment depth, (b) the height and pocket opening of the geocell, (c) the embedment depths and number of geogrids, (d) the distance between geogrids and (e) the stiffness of the geotextile on the bearing capacity of the unpaved road were investigated. Moreover, the same plate loading test was also conducted on an unpaved road built with VA. As a result of this study, although the performance of C&D was determined to be lower than that of VA, it was concluded that C&D performed well enough to be used as an alternative to VA on unpaved roads. Furthermore, with a very small number of geosynthetics, it was determined that C&D could have a better performance than VA.

In this study, the performance of unpaved road sections over soft clay soil geosynthetic-reinforced and stabilized with rock fill layer was evaluated using repeated plate loading tests. A total of 10 field tests were carried out using a circular model rigid plate with a diameter of 0.30 m. The parameters investigated included the location and type of geosynthetics and loading conditions (number of loading cycle and traffic loading condition). Based on the test results, the least deformation was observed in the rockfill section. The geocell placed at a depth of one-third thickness of the granular fill layer from the top showed improved performance and was more effective as compared with other geosynthetic reinforcements. However, for granular fill geosynthetic-reinforced or stabilized with rock fill layer, the results demonstrate an improvement in the rutting performance of the pavement and the definite trend of increasing reloading elastic modulus, depending on the traffic loading situation. It has been also observed that the use of geocell or geogrid reinforcement in granular fill layer or more rigid rockfill layer provides an important increase in the modulus improvement ratio (MIR) by at least 36%, 45% and 60% compared to the granular fill section, respectively.

Pamukkale University Journal of Engineering Sciences