UFC 3-250-03
15 May 2001
be used. ASTM D 1139 offers additional physical requirements for aggregates to be used in surface
treatments.
(b) Tables 4-2 and 4-3 give the recommended aggregate gradations for SBST and DBST,
respectively. The correlating size number designation from ASTM D 448 is also given. For DBST,
gradation Nos. 1 and 2 and gradation Nos. 3 and 4 from table 4-3 will be used in combination.
Table 4-2
Gradations for SBST
Percent Passing by Weight,
Gradation Designation
No. 1
No. 2
No. 3
(No. 61)
(No. 71)
(No. 81)
Sieve Size
25 mm (1 inch)
100
--
--
19 mm (3/4 inch)
90-100
100
--
12.7 mm (1/2 inch)
20-55
90-100
100
9.5 mm (3/8 inch)
0-15
40-70
85-100
4.75 mm (No. 4)
0-5
0-15
10-30
2.36 mm (No. 8)
0-5
0-10
1.18 mm (No. 16)
0-5
1
Number size designations from ASTM D 448.
Table 4-3
Gradations for DBST
Percent Passing by Weight, Gradation Designation
No. 1 (No. 61)
No. 2 (No. 81)
No. 3 (No. 71)
No. 4 (No. 91)
Sieve Size
(First Spreading) (Second Spreading) (First Spreading) (Second Spreading)
25 mm (1 inch)
100
--
--
--
19 mm (3/4 inch)
90-100
--
100
--
12.7 mm (1/2 inch)
20-55
100
90-100
--
9.5 mm (3/8 inch)
0-15
85-100
40-70
100
4.75 mm (No. 4)
0-5
10-30
0-15
85-100
2.36 mm (No. 8)
--
0-10
0-5
10-40
1.18 mm (No. 16)
--
0-5
--
0-10
300 Fm (No. 50)
--
--
--
0-5
1
Number size designation from ASTM D 448.
c. Design. The type and amount of aggregate and bitumen to be used for surface treatments can
be determined in accordance with ASTM D 1369. This practice provides guidance on typical rates of
4-3
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