Experimental investigation on reinforcement effect of sustainable materials for different subgrades

Through the physical model tests of subgrades under different working conditions, the feasibility of using waste tires and construction wastes as reinforced subgrades is investigated. The effects of compaction degree, subgrade material and reinforcement type on subgrade performance are studied. The test results show that the increase of compaction degree brings about an increase of the bearing capacity and initial stiffness of subgrades, inducing a settlement reduction. The load-settlement characteristics of construction waste subgrade are better than that of sandy subgrade, especially at a lower settlement. In general, with the development of footing settlement, the bearing capacity of reinforced sandy subgrade gradually exceeds the unreinforced one. With regard to the construction waste subgrade, the reinforced effect of both geocell and waste tire is better under high pressure, and the reinforced effect of waste tires is better than that of geocell under the same condition. Furthermore, construction waste can effectively reduce the uplift of the subgrade surface compared with the sandy soil, and the waste tires can help to redistribute the soil pressure into a wider space.