Assessment of In Situ Test Technology for Construction Control of Base Courses and Embankments; Technical summary rept

摘要

Soil compaction is considered a critical component in the construction of roads, embankments, and foundations. The durability and stability of these structures are related to the achievement of proper soil compaction. Therefore, compaction control of soils is necessary to improve their engineering properties. The current Louisiana state quality acceptance criteria for the construction of geomaterials is based on achieving adequate field density relative to a maximum dry density obtained in the laboratory by using standard or modified Proctor tests. However, the design of these materials is based on engineering parameters such as strength and stiffness. Any project is expected to use a durable material that can perform satisfactorily in the field throughout its expected design life. The missing link between the design process and field quality control makes implementing performance based specifications difficult. Therefore, the construction quality assurance/quality control (QA/QC) procedures should be based on criteria that closely correlates with the parameters used in the design in an attempt to ensure that the required performance levels are achieved. A fundamental performance parameter for evaluating the constructed highway layers is the elastic modulus of the materials used. Several nondestructive test devices can be used to measure the in situ elastic modulus of the construction materials, including the GeoGauge, the Light Falling Weight Deflectometer (LFWD), and the Dynamic Cone Penetrometer (DCP).