Lesson 1/Learning Event 3
The most common type of bituminous wearing surface that can be expected to be constructed in
the theater of operations is the surface treatment. Experience from the use of surface treatments
over base courses with CBR less than 80 has shown that constant maintenance is necessary.
Assume in the above example that the pavement could not be placed due to lack of materials and
equipment and surfacing would be limited to a multiple surface treatment. The construction in
this example problem is limited to the use of materials-of CBR 40 subbase and CBR 50 base
course. When Figure 6 was used in the above example, it was found that a minimum of 3/2
inches of pavement was required over the CBR 50 material. Since neither the pavement material
nor material higher than CBR 50 is available, it is necessary to use the CBR 50 material to meet
the cover requirements. Heavy maintenance will be required, however.
Figure 9, #2 illustrates the design for the multiple surface treatment.