UFC 3-270-01
15 March 2001
about 6 to 8 inches (150 to 200 millimeters). On the adjacent pass, aggregate should be applied
along the full spray width. After completing the work and opening the treated area to traffic,
speed limits should be posted to no more than 20 miles per hour (32 kilometers per hour) for a
few days. This will ensure that the asphalt is fully cured and prevent dislodging of additional
aggregate.
5.5. Multiple Bituminous Surface Treatment. This treatment is essentially the same as the
SBST, except that more than one application of binder and aggregate is used. The most
common treatment is the DBST. The same bituminous materials used for SBST can also be
used for DBST (Paragraph 5-2). Aggregate gradations to be used are shown in the following
table.
Table 5.3. Aggregate Graduations for DBST
% Passing by Weight, Gradation Designation
Sieve Size
No. 1
No. 2
No. 3
No. 4
1 in. (25.4 mm)
100
---
---
---
3/4 in. (19.1 mm)
90 - 100
---
100
---
1/2 in. (12.7 mm)
20 - 55
100
90 - 100
---
3/8 in. (9.5 mm)
0 - 15
85 - 100
40 - 70
100
No. 4 (4.8 mm)
0-5
10 - 30
0 - 15
85 - 100
No. 8 (2.4 mm)
---
0 - 10
0-5
10 - 40
No. 16 (1.2 mm)
---
0-5
---
0 - 10
---
---
---
0-5
No. 50 (300m)
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