Standard Hawai'i Mixes

HAPI Pavement Note on Hawai'i Mix Types

Differentiating between HDOT mix designations and County mix designations can be confusing. Prior to 1994, HDOT and the Counties used different mix designations with the State using roman numerals II, III, IV and V and the Counties using arabic numerals 2, 3, 4 and 5.

The State's 1994 Standard Specifications (commonly called the "grey book") attempted to standardize mix terminology throughout the State so that it conformed to State (HDOT) mix designations. However, some County specifications (especially in the City and County of Honolulu) still use the old County mix designations (2, 3, 4 and 5). Therefore, one must be extremely careful when specifying mixes to state which mix designation system is being used. For example, a mix conforming to HDOT Mix IV specifications should be referred to as a "State mix four" for clarity because a "County mix four" is quite different.

For consistency, this Guide will adhere to the original intent of the State's 1994 Standard Specifications and refer to all mixes by their HDOT mix designations (II, III, IV and V).

HAPI Pavement Note on Asphalt Content

HDOT expresses asphalt content in their mixtures as a percentage of the dry weight of aggregate in the mixture (which does not include the weight of asphalt in the mixture). Almost all other entities (County and private) express asphalt content in their mixtures as a percentage of the total dry weight of the mixture (which includes the weight of asphalt in the mixture).

As a rule-of-thumb, for the same HMA mix, the asphalt content expressed using HDOT's method (by total dry weight of aggregate) will be about 0.5% more than asphalt content expressed using the total dry weight of the mixture method.

Standard HDOT Mixes

State Mix II. Dense-graded HMA. The nominal maximum aggregate size is 1 inch and asphalt binder content ranges from 4.0 to 6.5 percent by weight of aggregate. This is essentially a deprecated mix; it has not been used for quite some time and is rarely, if ever, specified.
State Mix III. Dense-graded HMA primarily used in heavy-duty applications such as airfields and heavy industrial applications (like harbors) , but it can also be used as a binder course . The nominal maximum aggregate size is 0.75 inches and compacted lift thicknesses should be between 2 and 4 inches. Asphalt binder content ranges from 4.5 to 6.5 percent by weight of aggregate.
State Mix IV. Dense-graded HMA used for surface courses . This is the standard HDOT highway surface course mix. The nominal maximum aggregate size is 0.5 inches and compacted lift thicknesses should be between 1.75 and 3 inches. Asphalt binder content ranges from 4.5 to 6.6 percent by weight of aggregate. This mix is not recommended for parking lots because its surface finish can be a bit rough and it is more difficult to place and compact in the confined geometry of parking lots.
State Mix V. Dense-graded HMA used for surface courses . Common mix used for residential roads , collectors , parking lots , recreational facilities and paths . The nominal maximum aggregate size is 0.375 inches and compacted lift thicknesses range should be between 0.75 and 3 inches. Asphalt binder content ranges from 5.0 to 7.5 percent by weight of aggregate. Because of its smaller nominal maximum aggregate size, it is the best choice for thin lifts (less than 1.5 inches) and leveling courses .
Asphalt Concrete Base (ACB). Dense-graded HMA primarily used for binder courses and HMA base courses . The nominal maximum aggregate size is 1 inch and compacted lift thicknesses should be between 2.5 and 6 inches.

Figure 1: State Mix IV Over ACB

Standard County Mixes

County Mix 2. Dense-graded HMA. The nominal maximum aggregate size is 1 inch and asphalt binder content ranges from 4.5 to 6.5 percent by total dry weight of the mixture. Primarily used for binder courses and HMA base courses . This is quite similar to a State mix II .
County Mix 3. Seldom-used Dense-graded HMA intended for use as a HMA base course layer. The nominal maximum aggregate size is 0.75 inches and compacted lift thicknesses should be between 2 and 4 inches. Asphalt binder content ranges from 4.5 to 7.0 percent by total dry weight of the mixture. This is quite similar to a State mix III .
County Mix 4. Dense-graded HMA used for surface courses . This is the standard County surface course mix. The nominal maximum aggregate size is 0.375 inches and compacted and compacted lift thicknesses range should be between 0.75 and 3 inches. Asphalt binder content ranges from 5.5 to 7.5 percent by total dry weight of the mixture. This is similar to a State mix V (and not, as you might think, a State mix IV).
County Mix 5. Dense-graded HMA used for surface courses . Common mix used for driveways , parking lots , recreational facilities and paths . This mix is not recommended for roads. The nominal maximum aggregate size is less than 0.375 inches and compacted layer thicknesses range from 0.75 to 3 inches. Asphalt binder content ranges from 6.0 to 8.0 percent by total dry weight of the mixture. Because of its smaller nominal maximum aggregate size, it is the best choice for thin lifts (less than 1.75 inches) and leveling courses.
Asphalt Treated Base (ATB). Dense-graded HMA primarily used for binder courses and HMA base courses . The nominal maximum aggregate size is 1 inch and compacted lift thicknesses should be between 2.5 and 4 inches. Asphalt binder content ranges between 4.0 and 5.0 percent by dry weight of aggregate. Note that this method of expressing asphalt content is consistent with HDOT's method and not the County method used for mixes 2, 3, 4 and 5. This is similar to HDOT's ACB .

Superpave Mixes

Although they are currently not contained in the 1994 Standard Specifications for Road, Bridge and Public Works Construction, Superpave mixes have been and will continue to be used in Hawai'i. Superpave mixes are appropriate for both binder courses and surface courses of arterials and highways. Standard Superpave mix designations are 3/4 inch Superpave, 1/2 inch Superpave and 3/8 inch Superpave.