CITY AND COUNTY OF DENVER DEPARTMENT OF PUBLIC WORKS. CONTRACT NO.: PROJECT NAME: Platte River and Goldsmith Gulch Rehabilitations

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1 CITY AND COUNTY OF DENVER DEPARTMENT OF PUBLIC WORKS CONTRACT NO.: PROJECT NAME: Platte River and Goldsmith Gulch Rehabilitations ADDENDUM NO. _2_ TO CONTRACT DOCUMENTS Bidders are hereby instructed that the drawings, specifications, and other contract documents are modified, corrected, supplemented and/or superseded for the above-mentioned project as hereinafter described in the following attachments: PLANS Replace plan sheets Bl, B5, BIO and BI3 with the attached revised plan sheets BI, B5, BIO and Bl3. TECHNICAL SPECIFICATIONS - SCHEDULE B Remove Revision of Sections 401 & 403 Asphalt Pavement PSP-41 through PSP-42. Remove Revision of Section 401 Temperate Segregation PSP-43. Replace with Revision of Sections 401 Hot Mix Asphalt (Grading SX)(75) PSP-4 la through PSA-43A. This ADDENDUM shall be attached to, become a part of, and be returned with the Bid Proposal. The undersigned bidder acknowledges receipt of this Addendum. The Proposal submitted herewith is in accordance with the stipulations set forth herein. ADDENDUM NO. _2_ Date Contractor Contract No PR&GG ADD- #2 August 3, 20 I 7

2 REVISION OF SECTIONS 401 AND 403 HOT MIX ASPHALT (GRADING SX) (75) Section 401 of the Standard Specifications is hereby revised for this project as follows: In Subsection under Basis of Payment, delete the fifth paragraph. Section 403 of the Standard Specifications is hereby revised for this project as follows: Subsection shall include the following: The design mix for hot mix asphalt shall conform to the following: VALUE FOR PROPERTY Grading Air Voids, percent at N(des) Lab Compaction (Revolutions) Stability, minimum N(des) Aggregate retained on the No. 4 sieve with at least 2 Mechanically Induced fractured faces, % minimum Accelerated Moisture Susceptibility Tensile Strength Ratio (Lottman), minimum Minimum Dry Split Tensile Strength, psi (kpa) Grade of Asphalt Cement Voids in the Mineral Aggregate (VMA), % min Voids Filled with Asphalt (VF A), % Dust to Asphalt Ratio Fine Gradation Coarse Gradation TABLE TEST METHOD CPL 5115 CPL 5115 CPL 5106 CP45 CPL 5109 Method B CPL 5109 Method B CP48 AI MS-2 CP-50 CP-50 (SX75) (205) PG See TABLE Note: AI MS-2 =Asphalt Institute Manual Series 2 Note: The current version of CPL 5115 is available from the Region Materials Engineer Note: Mixes with gradations having less than 40% passing the No. 4 sieve shall be approached with caution because of constructability problems. Note: Gradations for mixes with a nominal maximum aggregate size of one-inch or larger are considered a coarse gradation if they pass below the maximum density line at the #4 screen. Gradations for mixes with a nominal maximum aggregate size of~ inch or smaller are considered a coarse gradation if they pass below the maximum density line at the #8 screen. PSP-41 A

3 REVISION OF SECTIONS 401 AND 403 HOT MIX ASPHALT (GRADING SX) (75) All mix designs shall be run with a gyratory compaction angle of 1.25 degrees and properties must satisfy Table Form 43 will establish construction targets for Asphalt Cement and all mix properties at Air Voids up to 1.0 percent below the mix design optimum. TABLE Minimum Voids in the Mineral Al!2re2ate (VMA) Nominal Maximum ***Design Air Voids** Size* Inches (mm) 3.5% 4.0% 4.5% 1 1/2 (37.5) (25.0) /4 (19.0) (12.5) /8 (9.5) * The nominal size is defined as one sieve larger than the first sieve to retain more than I 0% ** Interpolate specified VMA values for design air voids between those listed. *** Extrapolate specified VMA values for production air voids beyond those listed. The Contractor shall prepare a quality control plan outlining the steps taken to minimize segregation of HMA. This plan shall be submitted to the Engineer and approved prior to beginning the paving operations. When the Engineer determines that segregation is unacceptable, the paving shall stop and the cause of segregation shall be corrected before paving operations will be allowed to resume. A minimum of one percent hydrated lime by mass (weight) of the combined aggregate shall be added to the aggregate for all hot mix asphalt. Subsection shall include the following: If liquid anti-stripping additive is added at the plant, an approved in-line blender must be used. The blender shall be in the line from the storage tank to the drier drum or pugmill. The blender shall apply sufficient mixing action to thoroughly mix the asphalt cement and anti-stripping additive. PSP-42 A

4 REVISION OF SECTIONS 401 AND 403 HOT MIX ASPHALT (GRADING SX) (75) Delete subsection and replace with the following: The accepted quantities of hot mix asphalt will be paid for in accordance with subsection , at the contract unit price per ton for the bituminous mixture. Payment will be made under: Pay Item Hot Mix Asphalt (Grading SX) (75) (PG 64-28) Pay Unit Ton Aggregate, asphalt recycling agent, additives, hydrated lime, and all other work necessary to complete the hot mix asphalt item will not be paid for separately, but shall be included in the unit price bid. When the pay item includes the PG binder grade, the asphalt cement will not be measured and paid for separately, but shall be included in the work. When the pay item does not include the PG binder grade, asphalt cement will be measured and paid for in accordance with Section 411. PSP-43 A

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