<p><p><h2>Summary of Example Specifications</h2>Two specifications have been selected for inclusion in this document. These documents are representative of typical geosynthetic-reinforced pavement specifications but should be tailored for project‑specific conditions.<br><div class="grayed-title subsection"><strong>Specification Name/Number:</strong> AASHTO R 50-09</div><strong>Reference(s):<br></strong><em>Berg et al. (2000)<br>AASHTO M-288<br></em></p><p>The AASHTO R 50-09 Standard Practice for Geosynthetic Reinforcement of the Aggregate Base Course of Flexible Pavement Structures is a document that gives designers general guidelines for designing a pavement system and developing a performance specification for geosynthetic-reinforced pavements. The guide was created with the Empirical Design Method in mind, as it exclusively refers to the Traffic Benefit Ratio (TBR), the Base Course Reduction (BCR) factor, and the design steps in the GMA White Paper II (Berg et al. 2000). It may be possible to adapt this guide to the Mechanistic-Empirical Design Method. This specification is considered a performance/method approach specification because it contains minimal performance requirements (TBR and BCR) and method requirements.<br>The designer is directed to use the Empirical Design Method to first design an unreinforced pavement system, and then, based on empirical data of reinforced sections, design a system meeting TBR or BCR requirements. The designer can then develop a material specification or an approved list of accepted materials for the specification. The actual items necessary for a material specification are not covered in this guide, but are referred to in Berg et al. (2000) and Holtz et al. (2008).<br>This guide is not complete for all aspects of pavement construction. Items like site conditions, soil parameters, contractor qualifications, equipment, maintenance, QC/QA, measurement, and payment are not covered directly in this document.<br>This standard practice guide is clear for the limited information that is presented. It appears that most of the risk will be allocated to the designer and the ability to bid a project openly is limited by the Empirical Design Method requirement. The contractor must demonstrate that the material meets the performance specification through full scale testing. The guide does not give any information to the type of construction necessary; it is assumed that some construction direction will be given by a complete specification for geosynthetic reinforced pavement systems.<br><div class="grayed-title subsection"><strong>Specification Name/Number:</strong> FHWA NHI-070-92</div><strong>Reference(s):<br></strong><em>Holtz et al. (2008)</em></p><p>The FHWA NHI-07-092 is the Geosynthetic Design and Construction Guidelines Reference Manual. In this reference manual a method specification is presented for the geosynthetic reinforcement of pavement systems. This specification gives clearly defined material properties and a list of approved geosynthetics. Allowances for other geosynthetics that meet the specification material requirements or demonstrate performance equivalency through full-scale testing are allowed.<br>The specification is a material specification and the document states the difficulties associated with using a material specification for geosynthetic reinforcement.<br>“A typical, generic type material specification for geosynthetic reinforcement for pavements will be difficult to develop because of: the proprietary nature (i.e., current product patents) of biaxial geogrids and some geocomposites; a lack of thorough understanding of the mechanistic benefits of geosynthetic reinforcement; lack of performance documentation; and the inability to measure contribution of geosynthetic reinforcement to pavement structure with non-destructive methods.”<br>This specification is not complete for all aspects of pavement construction. Items like site conditions, soil parameters, contractor qualifications, equipment, maintenance, QC/QA, measurement, and payment are not covered directly in this document.<br>This specification in the reference manual is clear for the limited information that is presented. Most of the risk will be allocated to the designer. This specification is a material specification and will favor some geosynthetic materials over others. It does not give any information to the type of construction necessary; it is assumed that some construction direction will be given by a complete specification for geosynthetic reinforced pavement systems.</p></p>