| dc.description.abstract | In this study, the characterization of soils and granular materials and their variation with the compaction method is investigated. Impact hammer compaction is the most prevalent method for sample fabrication of granular materials in the laboratory. Factors such as low precision of unconfined strength test and the presence of interface between layers can be downsides of this compaction method. In this research, an alternative laboratory compaction method for granular materials is proposed and studied. The effects of using Superpave gyratory compactors (SGC) on the compaction and engineering properties of unbound granular materials used in transportation infrastructure is investigated. An experimental program is performed on the specimens compacted with both the gyratory compactor and impact hammer. Unconfined compressive strength tests are conducted to investigate whether using gyratory compaction can improve the precision of this test. Furthermore, maximum dry density and optimum moisture content are determined from each compaction technique. Statistical analyses are also performed on the experimental results to compare maximum dry density, optimum moisture content, and compressive strength in the studied materials. Permanent deformation and resilient modulus testing and modeling, as pavement performance-related characteristics used in the mechanistic-empirical design of pavements, are performed on the specimens fabricated with these two procedures. Variation of these characteristics with the compaction method is studied. Moreover, filter paper test to measure the soil suction, laser particle size analyzer to obtain percent of fines content, Percometer to measure dielectric constant, Methylene blue test, and Aggregate Imaging System (AIMS) tests are used. Therefore, the effects of material properties and compaction method are both investigated on the engineering behavior. The resilient modulus model incorporating suction, moisture conditions, and stress states is studied. Moreover, prediction models for the coefficients of the resilient modulus model are developed using the performance-related properties. The prediction models for the coefficients of the permanent deformation model are also developed using the performance related properties. Additionally, an equation for estimation of compaction energy is also developed to quantify the compaction effort required using gyratory compactor, that reveals substantial difference between base course materials. The results generally have shown that gyratory compactor produces a different mechanism of compaction from the impact hammer compaction. Furthermore, the prediction of conditions of granular materials using non-destructive testing techniques is investigated using the suction and dielectric constant. CT scanning also captures the difference between structure of the specimens compacted with the two methods. | en |
