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TRB Submission for Jan. 2012 Meeting AGENCY EXPERIENCE WITH BYPRODUCTS IN HIGHWAY APPLICATIONS Mary Stroup-Gardiner Gardiner Technical Services, LLC Gts_llc@hotmail.com ABSTRACT Highway applications are perceived by the public as useful means of disposal for a wide range of waste streams because of the large volume of materials used for highway projects. However, agencies need to consider any addition to a highway application as a construction material which should enhance the performance and/or lower cost of the final application. A total of 93 telephone interviews were conducted to document agency experiences with using byproducts in highway applications. Combinations of highway applications and byproducts represented with the interviews covered PCC applications using coal combustion, and iron, steel, and non-ferrous slags. Hot mix asphalt applications used mineral and quarry, scrap tire, and roofing shingles byproducts. Unbound applications (aggregates, embankments, fills) used coal combustion, scrap tire, cement kiln dust, recycled concrete aggregates, and iron, steel, and non-ferrous slag byproducts. An on-line survey of state materials engineers (46 agencies) was conducted for NCHRP 40-01 Use of Byproducts in Highway Applications. Along with the surveys, respondents were requested to provide contact information for staff with experience using byproducts in highway applications. This requested 85 contacts with experience with 92 combinations of byproducts and applications. This contact was used to conduct telephone interviews which showed that while there were a number of barriers that needed to be overcome by agencies, the benefits eventually overcame the barriers. The most common reasons for using byproducts in highway applications are the application are a good use of the byproduct, and it improves properties, improves performance, extends the life of the treatment, and is cost effective. Word count: Words = 4,495, 7 Tables (1,750 words), 1 Figure (250 words), Total words: 6,495 Keywords: Recycled materials, Portland cement concrete, Hot mix asphalt, Unbound materials INTRODUCTION Waste recycling in the early 1990’s began to focus on high volume discarded materials with potential recyclable value (Collins and Ciesielski 1994). Over the last two decades, a number of waste streams have become valuable byproducts in highway applications. Increasing public awareness of green house gas generation, diminishing non-renewable natural resources, and the need for environmentally responsible and resource-efficient (sustainable) construction is focusing more attention on increasing the use of recycled materials. Local, state, and federal programs are encouraging the use of current waste streams as value added byproducts. At the same time agencies and legislative bodies are restricting byproduct use with often conflicting environmental regulations, lack of standards for byproducts in specific highway applications, and arbitrary legislative efforts. Highway applications are perceived by the public as useful means of disposal for a wide range of waste streams because of the large volume of 1 TRB 2012 Annual Meeting Original paper submittal - not revised by author.
