Evaluation of Recycled Materials as Backfill for Geosynthetically Reinforced Mechanically Stabilized Earth (MSE) Walls

Recycled asphalt pavement (RAP) also satisfies general criteria for use in MSE backfill applications (e.g., grain size distribution, shear strength), but displays significant potential for deviatoric creep and thermal sensitivity due to its asphalt content. These issues require more attention for use of RAP in long-term applications. Similarly, foundry sand/slag, bottom ash, andiron/steel slag have suitable frictional and drainage properties. All of these materials, when compacted, display adequate friction angle required for MSE reinforced backfill. However,secondary issues such as compatibility with geosynthetic reinforcement, drainage, creep potential,and interface frictional behavior require more consideration.
The overall goal of this research is to facilitate use of RAP and RCA in reinforced backfills for MSE retaining wall construction. This thesis consists of five Chapters. In Chapter 1, the engineering properties of different types of recycled materials for potential use as backfill material are summarized from the literature. The design procedures for MSE walls, selection of backfill and geosynthetics, and current specifications are also summarized in Chapter 1. Chapter 2 summarizes issues related to responses of different types of recycled materials, as well as failure modes of MSE walls. The materials selected to conduct this research (including different types of geosynthetics and RAP and RCA samples) and testing procedures are described in Chapter 3. The experimental testing program includes index property tests, interface direct shear tests, pull-out tests and triaxial compression tests. Chapter 4 describes the test results and interpretation of the results. Chapter 5 summarizes the conclusions and recommendations from this research

The full thesis may be found in the following file:

Paulo Florio Master Thesis 2016