- The purpose of this study was to provide the USDA-Forest Service,
Bureau of Land Management (BLM), and other agencies or industries
that may deal with temporary and intermittent use roads with
the necessary background information for the identification, economic
evaluation, and selection of the alternate surfacing systems and to
determine the applicability and cost effectiveness of each system
compared with crushed aggregate roads. Alternate systems considered
include those which: 1) are capable of being moved as the hauling or
mining activity moves, 2) degrade after use, and 3) significantly
reduce the amount of rock required.
A comprehensive market and literature search was performed.
Potential surfacing types identified in this study are biodegradable
materials, chemical stabilization, geotextile or geogrid separation,
marginal aggregates, sand-sealed subgrade, metal mats, reusable
aggregate with or without geotextile separation, membrane-encapsulated
soil layer (MESL), and Geoweb stabilization. Numerous properties
of these materials are evaluated, including size, weight, cost,
expected performance, mechanical properties, and availability.
A two-step evaluation procedure is developed. First is the
preliminary evaluation step, which screens various alternate materials
based on their characteristics, limitations, and availability.
The second step is economic evaluation, which determines the most
feasible economical alternatives. Two examples are analyzed to
describe the evaluation procedure. The results of this analysis
indicate that alternate surfacings can be economical compared to
aggregate in most situations.
A probabilistic approach using the Beta estimation procedure is
recommended for the analysis and evaluation of the uncertainty associated
with various elements of the alternate surfacings. Furthermore,
a detailed sensitivity analysis is performed for crushed aggregate
and soil stabilization surfaces.
The results of this research indicate that the feasible alternatives
for surfacing temporary and intermittent use roads are biodegradable
materials, soil stabilization, marginal aggregates, conventional
geotextile and extruded plastic mats, steel mats (M8A1),
and sand-sealed native subgrade.