Lesson 2/Learning Event 1
L = weight of treated surface in feet
W = width of treated surface in feet
ARA = rate of application of aggregate in pounds per sq/yd.
ARB = rate of application of binder per pounds of aggregate per sq/yd.
LF = loss factor for bitumen 5% or 1.05
9 = square feet per square yard conversion factor
18,000 = 2,000 x 9 or pounds per ton and square feet per square yard conversion factor
The materials for a multiple surface treatment are determined by the same method as above
except that the application rate of the binder and the aggregate, and the size of the aggregate are
one-half that of the previous lift.
Example: A teat strip with an area of 100 square yards was used to determine the quantities for
a single surface treatment. Careful control was made of materials. A check of
materials consumed showed that 1.50 tons of aggregate was used. Based on previous
experience an aggregate loss of 10 percent (0.10) and a bitumen loss of 5 percent
(0.05) are expected. Find the tons of aggregate and drums of bitumen necessary to
make a double surface treatment on a road 24 feet wide and 10 miles long.
SOLUTION:
(2) Bitumen ARB = 0.01 gallon per lb of aggregate per sq/yd
1st Lift
20
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