Effective Utilization of Stone Powder in Road Construction Using Sandwich Technique: A Laboratory Study

A series of California Bearing Ratio (CBR) tests were performed on unreinforced and reinforced roads using natural woven jute geotextile (JGT) and woven polypropylene geotextile (PGT) reinforcements. Three different sands were used to understand the influence of sand-geotextile interface frictional properties on the optimum sand layer thickness (t). The CBR test results on reinforced (non-sandwich) conditions showed the optimum depth of JGT and PGT reinforcements are 0.4 times and 0.5 times the size of the loading plate, respectively. The improvement does not show any significant variation as compared to unreinforced conditions. Also, the test results showed the load-carrying capacity for the case of the sandwich condition increased to more than 1.3 times to 3.5 times depending upon the interface frictional properties of sand-geotextile. Based on the test conditions, the optimum thickness range of sand layers for all encapsulated reinforcement cases is determined. The test results proved the sand-geotextile interface frictional properties influenced the optimum thickness of encapsulated sand layers and the extent of improvement.