Alternative Backfill Materials for Geosynthetically Reinforced MSE Walls
Everton Fabício Viana Rezende1; Paulo Florio1; Ali Soleimanbeigi1; William Likos1
1 University of Wisconsin-Madison
Resumo
This study aims to facilitate the use of Recycled Concrete Aggregate (RCA) and Recycled Asphalt Pavement (RAP) in lieu of natural aggregates as alternative backfill for Mechanically Stabilized Earth (MSE) walls. Although several studies on RCA and RAP have been conducted for use in roadway construction applications (Soleimanbeigi et al. 2015; Anderson et al. 2009; FHWA 2004a; Soleimanbeigi 2012), only a few studies have been conducted to evaluate RCA and RAP for specific use as MSE wall backfill. The selection of RCA, RAP and Geosynthetic reinforcements considered costs and environmental benefits. The use of RCA and RAP as backfill can reduce the costs associated with mining and transportation of natural aggregates, which can dominate the total cost of a MSE wall. In addition, the disposal of RCA and RAP into landfills is costly and can pose environmental risks to air and groundwater alike. The suitability of RCA and RAP as backfill for geosynthetically reinforced MSE walls is investigated in this study. Mechanical interaction between these recycled aggregates with four types of geosynthetic is presented. The index and mechanical properties of RCA and RAP are measured. Interface shear resistance between geosynthetics and the recycled materials are measured using a pullout table and a large scale direct shear machine. Two types of geotextiles (woven and non-woven) and 2 types of geogrids (uniaxial and biaxial) are used. RCA particles are angular with rough surfaces and noticeable attached mortar. The material has 8.7% fines content and is classified as GP (e.g. poorly graded gravel) in the Unified Soil Classification System (USCS). The specific gravity of 2.56 was measured. A maximum dry unit weight of 19.5 kN/m3 was achieved at 11.0% optimum water content. RAP particles are medium, angular and exhibit rough surfaces. Bituminous coating is noticeable around the surface of the particles. RAP has approximately 5.10% of fines and was classified as SP (e.g. poorly graded sand) in the USCS. The specific gravi
Palavras-chave: MSE Wall; Geosynthetics; RCA; RAP; Alternative Backfill; Recycled materials