Difference between revisions of "Hot Mix Asphalt Production Manual"

Latest revision as of 15:14, 19 June 2017

The Construction Field Services (CFS) Division has revised the Hot Mix Asphalt (HMA) Production Manual. A brief description of the major revisions is presented below.

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General

Updates made to formatting of the document and table of contents.

Section 1: Procedures Manual for HMA Mix Design Processing

Marshall Mixtures – Subsection 4: Comment added “2C Designs require 7000g of mixture at optimum”; plus some rearranging of information. (Page 6)
Marshall Mixtures – Subsection 5: Added two new points at the end. (Page 6)
Superpave Comparison Level Design Submittal-Subsection 4: Removed “2-1500 grams samples of mixture (Virgin Mix Design only)” and “2-1900 grams samples of mixture “Reclaimed Asphalt Pavement Mixture only”; plus some rearranging of information. (Pages 11, 12)
Superpave Comparison Level Design Submittal-Subsection 5: Added two new points at the end. (Pages 12, 13)
Aggregate Requirements-Subsection 3: Added new note “AWI will not be assigned to previously approved mix designs. MDOT will approve AWI for any design that can be used as a top course.” (Page 24)
New sub-section added under “Calculations” as “4”: Mix Designs with Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS)”. (Page 19)
Aggregate Requirements-Subsection 4“10% Minimum Aggregate Requirement”: Removed. (Page 24)

Section 3: HMA QA/QC Procedures for Field Testing

HMA Sample Reduction Procedure (Page 46)

Figure added.
First point moved to last.
Some verbiage changed/modified.

Bulk Density Procedure

Removed.

Checklist for Gyratory Compactor (Page 49)

Last two sentences of point 4 moved to point 2.
Additional information added on how to ensure saturated surface dry gyratory specimen.

Extraction Procedures (Page 51)

Checklist for HMA Mixture Analysis Centrifuge Extraction removed.

Checklist for HMA Mixture Analysis Vacuum Extraction (Page 51)

Point 8 was reworded as follows: “If the sample weight exceeds 2000 grams, it shall be split into two extractions. The weights from both extractions shall be combined before calculating percentages.”

Checklist for Ignition Furnace (Page 54)

Removed.
The following information was added regarding Ignition Furnace: Procedure; Contractor's Responsibilities for the Establishment of Ignition Oven Correction Factors; Calibration of Balance; Lift Test; Temperature Verification inside the Ignition Furnace (In-House Procedure); Maintenance;

Formulas for Calculating Asphalt and VMA (Page 60)

Title changed, formulas updated.

Procedure for Determining Pavement Density (Page 62)

Contents divided into Dry Back Method and Core Dry Method.

Rounding Off Method (Page 64)

Title changed to “Rounding Method”; ASTM E29-93a changed to ASTM E29-08; three additional examples added.

Core Handling and Transporting Procedure (Page 67)

Two additional points added:
- 9. Contractor may provide his own core transport/storage device.
- 10. If no core transport/storage device is provided, the core transporting procedures will be agreed upon at the pre-production meeting.

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Section 4: HMA Lab and Technician Qualification Program

Table: Minimum Test Methods Required for QA/QC Laboratory Qualification.
Marshall Test Procedure removed; Ignition Method, Fine Aggregate and Coarse Aggregate Specific Gravity added to the Table.
Section 4 was removed from the MDOT HMA Production Manual and added to Section 5.03.01 of the MDOT Materials Quality Assurance Procedures Manual (MDOT MQAPM).

The updated manual is available online at: http://www.michigan.gov/documents/mdot_HMA_ProductionManual_79005_7.pdf