Category:450 Bituminous Pavement Design
Payment for asphaltic concrete by the square yard (m2) should only be used for full depth asphaltic concrete pavements on alternate bid projects. All other payment for asphaltic concrete should be by the ton (Mg). For preliminary design, estimate factors may be used to compute quantities for bases, flexible type pavements, seal coats, etc. For final design, the designer should request estimate factors for anticipated rock formations from the district operations engineer to obtain more reliable results. When payment is by the ton (Mg), estimate factors should be shown on the plans with a note “For Information Purposes Only.” When payment is by the square yard [m2], estimate factors should not be shown on the plans.
AUTOMATIC SCREED CONTROL OR ESTABLISHED GRADE REFERENCE. The standard specifications require the use of automatic screed controls with the sensor following a traveling reference plane. In some instances, such as a badly warped pavement or very poor riding condition, the use of an established grade reference may be desirable. If the established grade reference is desired, a special provision must be included in the contract requiring its use for the initial pass of the paver when placing the first continuous layer. The special provision may be modified to require the established grade reference for a portion of a project if necessary.
COMMERCIAL MIXTURES. The standard specifications permit the use of approved commercial mixture for plant mix bituminous pavement and plant mix bituminous base course when so specified in the contract. Commercial mixtures are not permitted where Section 403 or Superpave mixtures are specified. Care should be exercised when setting up small quantities of asphaltic concrete in that it may be more desirable, all factors considered, to use plant mix bituminous pavement so that a commercial mixture can be permitted. The same mixtures specified for the traveled way should be placed on the shoulders. For projects with Type A2 shoulders to be built in conjunction with PCCP for the traveled way, specify PMBP over PMBB.