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2024 Pavement Maintenance Overlay SPECIAL PROVISIONS PW# 3823 45 • The proposed HMA mix design on WSDOT Form 350-042 with the seal and 1 certification (stamp & signature) of a valid licensed Washington State 2 Professional Engineer. 3 • The Mix Design Report for the proposed HMA mix design developed by a 4 qualified City or County laboratory that is within one year of the approval date.** 5 6 The mix design shall be performed by a lab accredited by a national authority such as 7 Laboratory Accreditation Bureau, L-A-B for Construction Materials Testing, The 8 Construction Materials Engineering Council (CMEC’s) ISO 17025 or AASHTO 9 Accreditation Program (AAP) and shall supply evidence of participation in the AASHTO: 10 resource proficiency sample program. 11 12 Mix designs for HMA accepted by Nonstatistical evaluation shall; 13 14 • Have the aggregate structure and asphalt binder content determined in 15 accordance with WSDOT Standard Operating Procedure 732 and meet the 16 requirements of Sections 9-03.8(2), except that Hamburg testing for ruts and 17 stripping are at the discretion of the Engineer, and 9-03.8(6). 18 • Have anti-strip requirements, if any, for the proposed mix design determined in 19 accordance with AASHTO T 283 or T 324, or based on historic anti-strip and 20 aggregate source compatibility from previous WSDOT lab testing. 21 22 At the discretion of the Engineer, agencies may accept verified mix designs older than 12 23 months from the original verification date with a certification from the Contractor that the 24 materials and sources are the same as those shown on the original mix design. 25 26 Commercial Evaluation Approval of a mix design for “Commercial Evaluation” will be 27 based on a review of the Contractor’s submittal of WSDOT Form 350-042 (For 28 commercial mixes, AASHTO T 324 evaluation is not required) or a Mix Design from the 29 current WSDOT QPL or from one of the processes allowed by this section. Testing of the 30 HMA by the Contracting Agency for mix design approval is not required. 31 32 For the Bid Item Commercial HMA, the Contractor shall select a class of HMA and 33 design level of Equivalent Single Axle Loads (ESAL’s) appropriate for the required use. 34 35 5-04.2(2)A Vacant 36 37 5-04.2(2)B Using Warm Mix Asphalt Processes 38 The Contractor may elect to use additives that reduce the optimum mixing temperature 39 or serve as a compaction aid for producing HMA. Additives include organic additives, 40 chemical additives and foaming processes. The use of Additives is subject to the 41 following: 42 43 • Do not use additives that reduce the mixing temperature more than allowed in 44 Section 5-04.3(6) in the production of mixtures. 45 • Before using additives, obtain the Engineer’s approval using WSDOT Form 350-46 076 to describe the proposed additive and process. 47 48