Types of Recycled Solid Wastes

In addition to virgin materials, transportation agencies have been actively encouraging the use of waste and recycled materials for many years (Table 1). Recent legislated mandates led many agencies to expand their use of waste and by-products. The following sections discuss the various solid wastes that have been used in several highway applications. 

2 Blast furnace slag BFS 14 million t (15.4 million T) 13 Plastics PL 44.7 million t (40.2 million T) 

3 Carpet fiber dusts 1.2 million t (1.32 million T) 14 Quarry by-products QBP 3.6 billion t (4 billion T) 

4 Coal bottom ash/ boiler slag BA/BS 53.5 million t (59.4 million T) 15 Reclaimed asphalt pavement RAP NR 

5 Coal fly ash FA 45 million t (49.6 million T) 16 Reclaimed concrete material RCM NR 

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