ETL 1110-3-503
15 Sept 99
to 20 percent of the cement with an equal weight of the rice husk ash contributed to
increased early (1 to 3 days) compressive strength and a decreased effect of alkali-
aggregate reactivity (Mehta 1992). The second investigation involved converting
cellulosic wastes (including crop residues, animal manure, and wood wastes) into binder
materials. These materials could be converted into an oil that could serve as an asphalt
extender (Collins and Ciesielski 1994 and Mehta 1992).
b. Logging wastes. About one third of the wood that is harvested yearly by the
logging and lumber industry ends up as a waste material. This waste takes the form of
logging residues, wood and bark chips, and sawdust. Cur rently, up to 70 million tons of
this material is produced in the U.S. each year (Collins and Ciesielski 1994). The
majority of this material is available in the Pacific Coast states. However, some would be
available throughout many parts of the U.S. where logging occurs. A portion of the wood
chips produced is used in the lumber industry to produce particleboard products. Finer
particles have usually been used as mulching materials. Some wood waste materials have
been used for exotic proposes such as soil reinforcement; however, the majority of use
for pavement applications has been as lightweight fill (Sotir and Gray 1989, ENR 1986,
and Nelson and Allen 1974).
B-3. Types and Pavement Applications of Domestic Waste. The amount of domestic
wastes generated in the U.S. annually exceed 200 million tons (Shelburne and DeGroot
1998). Approximately 185 million tons of this waste is household or commercial waste
(trash or garbage) (NSWMA 1989). About 75 percent of this waste is placed in landfills,
11 percent is recycled, and 14 percent is incinerated.
process of decomposition of organic wastes. These wastes can include a wide range of
materials including: crop wastes, sewage sludge, yard wastes, paper mill sludge, and food
wastes (Collins and Ciesielski 1994). Compost has been used on highway and airport
shoulders; although, some concerns with possible leachate problems, odors, worker
health and safety, and public acceptance hinder the use of this material in many areas
(Ahmed 1991 and Thoresen 1993). There are no specific regulations, standards, or
guidelines pertaining to the use of compost (Ahmed 1991).
b. Glass and ceramics. Despite the increased usage of plastics for many
applications, supplies of waste glass continue to be available, often due to recycling
efforts. In 1988, 1.5 million tons of waste glass was recycled, while three years later
12.5 million tons of glass was still being discarded (NSWMA 1990). This amount can be
expected to decline but not to be completely eliminated because of the decrease in the
production of glass containers (Ahmed 1991). Currently, glass is only available in
quantity in larger metropolitan areas (Collins and Ciesielski 1994), although recycling
operations in smaller metropolitan areas can also generate considerable quantities
(American City and County 1997). Waste glass, from an economical standpoint, should
probably be used only to make more glass; however, only selected glass can be used for
this process. This leaves a substantial amount of waste glass available for use in
pavement applications (Ahmed 1991). Ceramic waste consists of china and porcelain
from old or defective manufactured objects (Collins and Ciesielski 1994). This waste has
B-4
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