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Roller Compacted No-Fines Concrete
Containing We Energies Fly Ash for Road
Base Course
Many problems associated with pavement failure are due to the pressure of
water under rigid surface pavements. When high pressure from heavy traffic is
applied on pavements in the presence of water, pumping occurs. Pumping
causes erosion of the pavement base, as fines along with water are pumped
out. The continued effect of pumping is a loss of support, leading to pavement
failure. An open-graded permeable base is used to avoid such problems. The
open-graded permeable base pavement system consists of a permeable base,
separator layer and edge drainage. Permeable bases can be treated or untreated
with cementitious binders.
A demonstration project was designed to use an off-spec ASTM C618, Class
F fly ash in the open-graded concrete base course and an ASTM C618 Class C
fly ash in the concrete pavement for an internal road at the Port Washington
Power Plant located in Port Washington, Wisconsin.
The roadway cross section (see Figures 4-25 and 4-26) consisted of an initial
layer of filter fabric installed to prevent fines from the subgrade moving up
and blocking drainage in the base course, topped by a 6” thick layer of opengraded
concrete base course and a 10 in. thick, high-volume fly ash concrete
pavement. This pavement was designed in compliance with Wisconsin DOT
standards, with the exception of using high-volume fly ash in the open-graded
base, and concrete pavement. Underdrains, manholes and storm sewer piping
were also installed as part of this project, to ensure proper functioning of the
pavement system (32).
The properties of fly ash and cement used in this project are shown on
Table 4-41. The ASTM C618, Class F fly ash used on the project is offspecification
with a very high LOI.
The mixture proportions for the open-graded base course were composed of
160 lb./cu. yd. cement, 125 lb./cu. yd. fly ash, 81 lb./cu. yd. water,
2600 lb./cu. yd. ¾ in. coarse aggregate and no fine aggregate.
The mixture proportions for high-volume fly ash concrete pavement included
300 lb./cu. yd. cement, 300 lb./cu. yd. Class C fly ash, 221 lb./cu. yd. water,
1200 lb./cu. yd. sand, 966 lb./cu. yd. ¾” aggregate and 966 lb./cu. yd. 1½”
coarse aggregate. The water to cementitious materials ratio was maintained at
about 0.37.
We Energies 108
Coal Combustion Products
Utilization Handbook