This lab report was conducted to design Hot Mix Asphalt for a project in Fayetteville, Arkansas. The tests were conducted in compliance with current specifications for Superpave set forth by AASHTO and AHTD.
The topics covered in the lab report are selection of materials, selection of mix design, and final recommendation.
Even though other properties of the mixture just meet the Superpave design requirements, no job mix formula is drawn from this mix design because the dust proportion of the mixture is far out of the requirements. We may need to change the blend gradation of aggregate.
The blend in this mix design produced a gradation, as shown in Figure 1, that was close to the maximum criteria for the 2.36mm sieve and the 0.075mm sieve and passed above the restricted zone, so this blend was probably a fine blend. Therefore, the dust proportion of mixture was so high that it was far out of the requirements. We may need to change the cold feed so that a new gradation will pass under the gradation of this mix design. Moreover, the new gradation needs to meet the requirements for gradation and consensus/source properties that this blend gradation did not meet and to give safety rooms for other properties of mixture because the construction may have serious problems when most properties of this mix design are just on the criterion lines.
A. OBJECTIVE This lab report was conducted to design Hot Mix Asphalt for a project in Fayetteville, Arkansas. The tests were conducted in compliance with current specifications for Superpave set forth by AASHTO and AHTD. B. APPLICABLE SPECIFICATIONS 1. Applicable Specifications for Testing: a. AHTD 465: Procedure for Sampling by Random Number Table b. AASHTO T 2 – 91: Standard Specification for Sampling of Aggregates c. AASHTO T 248 – 95: Standard Method of Test for Reducing Samples of Aggregate to Testing Size d. AASHTO T 11 – 91: Standard Specification for Materials Finer Than 75-µm (No. 200) Sieve in Mineral Aggregates by Washing e. AASHTO T 27 – 97: Standard Specification for Sieve Analysis of Fine and Coarse Aggregates f. AASHTO T 255 – 92: Standard Method of Test for Total Moisture Content of Aggregate by Drying g. AASHTO T 84 – 95: Standard Specification for Specific Gravity and Absorption of Fine Aggregate h. AASHTO T 85 – 91: Standard Specification for Specific Gravity and Absorption of Coarse Aggregate i. AASHTO T 166 – 91: Standard Specification for Bulk Specific Gravity of Compacted Bituminous Mixtures Using Saturated Surface-Dry Specimens j. AASHTO T 209 – 94: Standard Specification for Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures k. AASHTO T 269 – 94: Standard Method of Test for Percent Air Voids in Compacted Dense and Open Bituminous Paving Mixtures
AASHTO TP4 – 99: Standard Method for Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens by Means of the SHRP Gyratory Compactor
m. AHTD 449/449A: Method of Test for Determination of Asphalt Content of Asphalt Mixtures by the Nuclear Method 2. Applicable Specifications for Superpave Mix Design a. AASHTO MP2 – 99: Standard Specification for Superpave Volumetric Mix Design b. AASHTO PP28 – 99: Standard Practice for Superpave Volumetric Design for Hot Mix Asphalt (HMA) c. AHTD SS – 400 – 1: Supplemental Specification: Asphalt Concrte Hot Mix Base, Binder, and Surface Course C. MIX DESIGN CALCULATION 1. Input Data for Mix Design a. Design traffic, 20-year period (from Assignment 1): b. Weather data (from the class sample): 19.6 mil. (ESAL)
Table 1: Weather Data.
Station I.D.: County: Station:
0032443 Washington Fayetteville FAA AP
Latitude: Longitude: Elevation, m:
36.00 94.17 381
Air Temperature High 7-day air temperature, C Low air temp, oC o
Mean 35.4 -18.7
Std. Dev. 2.1 4.2
c. Test results attached in Appendix 1.
2. Material Selection a. Binder Selection...