A02.11_PWS_PCCandHMAAirfieldPavementModel.pdf

PERFORMANCE WORK STATEMENT

Removal and Installation of

Airfield-Quality PCC and HMA Full-Scale Pavement Model

SCOPE

The Airfields and Pavements Branch of the U.S. Army Engineer Research and Development Center (ERDC), Geotechnical and Structures Laboratory (GSL) has been tasked to develop, test, and demonstrate a rapidly-emplaced, high-performing cement product for the repair and restoration of essential infrastructure such as airfield pavements. The tests will be conducted at GSL’s Outdoor Pavement Test Facility in Vicksburg, MS, and will require the installation of a full-scale portland cement concrete (PCC) and hot-mix asphalt (HMA) model. The test area currently holds an existing full-scale PCC model with varying surface thicknesses of 10- to 14-in.

The existing PCC model (surface and base material) will be removed, and a new full-scale PCC and HMA model (pavement surface and well-graded, crushed limestone base material) will be put in its place to simulate real life, high-quality airfield pavements for the high-performing concrete repair testing.

REMOVAL OF EXISTING PCC AND HMA MODEL

The existing full-scale model (50 ft by 285 ft) located at the GSL’s Outdoor Pavement Test Facility needs to be removed (primarily 10- to 14-in.-thick PCC over 6- and 9-in.-thick limestone base) and the debris hauled off site from ERDC. The perimeter of the existing PCC model does contain dowels. Several areas of the current model have 10-in.-thick rapid-setting concrete repairs with foam and flowable fill backfill. Some interior PCC slabs were placed with PCC mixtures of varying aggregates such as crushed brick, crushed concrete, crushed limestone, and reclaimed asphalt pavement (RAP). Six PCC slabs have been replaced with 4-in.-thick HMA over 20 in. of rapid-setting flowable fill. Figure 1 shows the existing PCC model to be removed, and Figure 2 shows pictures of the existing PCC model. The contractor will be responsible for the following:

1. Break up and remove 10- to 14-in.-thick PCC surface and any existing 10-in.-thick rapid-setting concrete and 4-in.-thick HMA surfaces

2. Remove crushed limestone, foam, and flowable fill base course material

3. Haul away all PCC, rapid-setting concrete, flowable fill, foam, and limestone debris

4. Compact the existing subgrade.

5. Daily site cleanup of all trash and debris.

INSTALLATION OF NEW PCC AND HMA MODEL

Once the existing full-scale model is removed, a new full-scale PCC (15 in. thick over 6 in. crushed limestone base) and HMA (8 in. thick over 8 in. crushed limestone) model (50 ft by 285 ft) is needed. Figure 3 depicts the plan and profile views of the new PCC and HMA model. The Contractor will install 15-in.-thick PCC slabs on a well-graded, crushed limestone base using a fixed form placement method for the PCC part of the model and an 8-in.-thick HMA wearing surface on the HMA part of the model. The existing silt subgrade may need material added and compacted to maintain the proper elevation. The new full-scale model will have free edges on all four sides. The contractor will be responsible for the following:

• The Contractor shall provide a crushed limestone base course layer placed under the PCC and HMA pavements, complete and in-place, meeting the following requirements:

1. Gradation requirements for the graded crushed limestone base course are shown in Table

1.

Table 1. Gradation Requirements for Crushed Limestone Base Material.

Sieve Designation Percentage by Weight Passing Square-Mesh Sieve

No. 1 No. 2 No. 2 50-mm (2-in.) 100 ----- ----- 37.5-mm (1½-in.) 70-100 100 ----- 25-mm (1-in.) 45-80 60-100 100 12.5-mm (½-in.) 30-60 30-65 40-70 4.75-mm (No. 4) 20-50 20-50 20-50 2.0-mm (No. 10) 15-40 15-40 15-40 0.425-mm (No. 40) 5-25 5-25 5-25 0.075-mm (No. 200) 0-8 0-8 0-8

2. The crushed limestone shall be placed at 95 percent of optimum density and moisture content, as measured in a laboratory (ASTM D1557).

3. The percentage of loss shall not exceed 50 when tested in accordance with ASTM C131.

The crushed limestone shall also meet the requirements listed in CEGS 02722 for flat and elongated particles, liquid limit, plasticity index, and magnesium sulfate soundness when tested in accordance with ASTM C88.

4. Compacted silt may need to be added to the existing subgrade to maintain the proper elevation.

5. The well-graded, crushed limestone base course material will be 6 in. thick under the PCC area (50 ft by 105 ft).

6. The well-graded, crushed limestone base course material will be 8 in. thick under the HMA area (50 ft by 180 ft).

7. Daily site cleanup of all trash and debris is required.

• The Contractor shall provide a PCC surface course, complete and in-place, meeting the following requirements:

1. Fixed Formed Placement

a. Placed to grade; the Contractor is to place on top of the limestone base material.

Follow the as-built slope (1 percent fall to the west) made to drain water.

b. Ensure forms are structurally sufficient and staked to the prepared base surface to support the 15-in.-thick PCC.

c. Form release shall be used to facilitate stripping of forms.

d. The Contractor is responsible for the supply, installation, removal, and disposal of all formwork.

2. Concrete Materials

a. Concrete shall have a design compressive strength of 5,000 psi at 28 days with a water-cement ratio of 0.45 or less and a 6 ± 1 percent air content by ASTM C231;

the mix design shall be approved by ERDC prior to placement.

b. Concrete shall have a flexural strength of 650 psi at 28 days by ASTM C78.

c. Size 67 or larger (e.g., Size 57) limestone aggregate by ASTM C33 will be used in the mix.

d. The target slump by ASTM C143 will be 3 ± 1 in. when placed directly from a concrete mix truck and 7 ± 1 in. when placed by pump truck. Slumps greater than 8 in. for pump truck placement WILL BE rejected.

e. Delivered concrete temperatures must be less than 90°F by ASTM C1064.

Deliveries exceeding this requirement WILL BE rejected.

f. Water in excess of the batch water is NOT allowed to be added except when, on arrival at the job site, the slump is less than specified and the water-cement ratio is less than that given in the approved mix design. Water may be added to bring the slump into tolerance provided the maximum allowable water-cement ratio is not exceeded. Water must be added into the mix truck and mixed thoroughly; water may not be added to the batch in any other method.

3. Concrete Placement

a. Concrete slab sizes will be 12.5 ft by 15 ft as shown in Figure 3. Slab thicknesses will be 15 in. (50 ft by 105 ft).

b. PCC mixture may be placed directly from a concrete mix truck or by pump truck provided by the Contractor. Where placing from a concrete mix truck would require traversing any new concrete, a pump truck will be required.

c. Placement and Forming Plan – The Contractor may decide how to place the concrete; however, the placement plan must be approved by the ERDC engineer.

g. Use of a self-powered, vibratory truss screed is required.

h. Concrete will be screeded to match the grade of the forms. Smoothness tolerances will be ± 1/4 in. measured by a 12-ft-long straightedge in both longitudinal and transverse directions.

4. Dowels – No dowels will be used in the test section.

5. Finishing and Curing

a. A textured broom finish is required with no additional water added to the surface.

A “slick” floor finish is not allowed.

b. Fogging/misting is allowed to prevent shrinkage cracking.

c. A CRD-C 300 curing compound is to be applied to the surface after finishing

(before saw cutting contraction joints) and as soon as the free water has disappeared. The curing compound is to be applied to the free edges as soon as forms are removed. Curing compound should be applied by a pressure sprayer with overlapping coverage in two coats. The second coat should be sprayed at a right angle to the first.

6. Construction and Contraction Joints

a. For purposes of this contract, construction joints are defined as a joint between PCC slabs which are existing or new and exhibit a smooth between-slab interface as a result of forms (e.g., separate paving lanes); contraction joints are defined as a joint between new PCC slabs in the same paving lane used to control cracking due to concrete volume change.

b. All contraction joints MUST undergo initial saw cutting within 6 to 12 hours after placement. If the PCC is chipping, spalling, or tearing during saw cutting, then saw cutting should be stopped until the PCC hardens more. Contraction joints should be sawn to a depth of 5 in. and a width of 1/8 in. over the full slab length and width.

Slabs will be replaced at no cost to ERDC if the PCC cracks before saw cutting is completed. A saw-cutting plan must be approved by the ERDC engineer before the PCC is placed.

c. Saw-cutting is not required for any construction joints, if applicable.

d. Joint sealant is not required for the model for the contraction joints; however, an expansion joint IS required between the PCC and HMA interface. Expansion joint is not required between paving lanes.

7. Daily site cleanup of all trash and debris is required.

• The Contractor shall provide an HMA surface course, complete and in-place, meeting the following requirements:

1. Aggregates

a. Coarse aggregate (defined as material retained on the No. 4 sieve (4.75 mm)) shall consist of sound, tough, and durable particles free from material films that would prevent thorough coating and bonding with the asphalt material and free from organic matter and other deleterious substances. Provide coarse aggregate meeting the following requirements:

i. The percentage of loss shall not be greater than 40 percent after 500 revolutions when tested in accordance with ASTM C131.

ii. The magnesium sulfate soundness loss shall not exceed 18 percent after five cycles when tested in accordance with ASTM C88.

iii. Coarse aggregate shall consist of at least 75 percent by weight of coarse aggregate containing at least two mechanically fractured faces when tested in accordance with ASTM D5821.

iv. Coarse aggregate shall be generally cubical in shape and contain no greater than 20 percent flat and elongated particles at a 3:1 ratio when tested in accordance with ASTM D4791.

v. Clay lumps and friable particles shall not exceed 0.3 percent by weight when tested in accordance with ASTM C142.

b. Fine aggregate (defined as material passing the No. 4 sieve (4.75 mm) and retained on the No. 200 sieve (0.075 mm)) shall consist of clean, sound, tough, and durable particles free from clay, silt, or any objectionable material. Provide fine aggregate meeting the following requirements:

i. Quantity of natural sand added to the aggregate blend shall not exceed 15 percent by weight of total aggregate.

ii. Individual fine aggregate sources shall have a sand equivalent value greater than 45 when tested in accordance with ASTM D2419.

iii. The fine aggregate portion of the blended aggregate shall have an uncompacted void content (fine aggregate angularity) greater than 45 percent when tested in accordance with ASTM T304 Method A.

iv. Clay lumps and friable particles shall not exceed 0.3 percent by weight when tested in accordance with ASTM C142.

c. Mineral filler (defined as material passing the No. 200 sieve (0.075 mm)) shall consist of a non-plastic material meeting the requirements of ASTM D242.

d. Provide a combined aggregate gradation that conforms to the design master range specified in Table 2, when tested in accordance with ASTM C136 and ASTM C117.

The gradation shall be uniform from coarse to fine and not vary from the low limit on one sieve to the high limit on the adjacent sieve or vice versa.

Table 2. Combined Aggregate Gradation Master Range.

Sieve Size Percent Passing By Mass

1.0 in. (12.5 mm) 100 3/8 in. (9.5 mm) 90-100 No. 4 (4.75 mm) 58-78 No. 8 (2.36 mm) 40-60 No. 16 (1.18 mm) 28-48 No. 30 (0.600 mm) 18-38 No. 50 (0.300 mm) 11-27 No. 100 (0.150 mm) 6-18 No. 200 (0.075 mm) 3-6

2. RAP shall not be allowed for the project.

3. Asphalt Binder – Asphalt binder shall conform to AASHTO M320 Performance Grade

(PG) 67-22. The ERDC engineer may sample and test the binder at the mix production plant at any time before or during mix production.

4. Mix Design – The mixture proportions shall be designed using a Superpave gyratory compactor set at 75 gyrations. The mixture properties shall meet the criteria shown in Table

3. The proposed mix design shall be submitted to the ERDC engineer at least 7 days prior to production of the model. No mixture shall be placed prior to the ERDC engineer’s approval.

Table 3. Superpave Gyratory Compaction Criteria.

Property Value Air voids (%) 4

VMA (%) 15

Dust/Binder Ratio 0.8-1.2 TSR (minimum %) 75

5. Installation

a. The Contractor shall provide the necessary equipment to spread, finish, and compact the HMA test section. Production and placement equipment shall be in good working order and meet the applicable requirements of Section 401 of the latest edition of the Mississippi Department of Transportation Standard Specifications for Road and Bridge Construction.

b. Physical dimensions for the HMA test section are 50 ft wide by 180 ft long. The HMA will be placed on top of a surface (prepared by the Contractor) consisting of an 8-in.-thick crushed limestone base course. The HMA shall be placed in four

12.5-ft.-wide paving lanes. Final compacted minimum HMA thickness shall be 8 in., as shown in Figure 3.

c. At least 7 days prior to HMA placement, the Contractor shall submit, in writing, a paving plan to provide proposed placement sequencing.

d. It is the intent of these specifications that the final compacted HMA thickness be 8

in. ± 0.5 in. Surface elevations of the final compacted HMA will be measured by ERDC using rod and level and total station measurement techniques along the centerline of each completed lane at approximately 12-in. intervals. If it is found that the HMA thickness is less than 7.5 in., the test item shall be removed and replaced at no cost to ERDC. If it is found that HMA thickness exceeds 8.5 in., the section shall be diamond ground.

e. Mat density shall be 92 to 96 percent of theoretical maximum density (TMD) and will be measured based on the average of three cores randomly obtained by ERDC.

If test results fail to meet the required density, the test section shall be removed and replaced at no cost to ERDC.

f. A tack coat shall be used to bond the HMA layers, where applicable. The tack coat shall be a cationic slow set emulsion (CSS-1) applied at a rate of 0.03 gal/yd2. Other products and/or application rates must be approved by the ERDC engineer.

6. Diamond Grinding

a. Areas exceeding the design thickness by more than 0.5 in. shall be diamond ground.

The grinding equipment shall be a power driven, self-propelled machine that is specifically designed to smooth and texture pavement surfaces with diamond blades. The effective wheel base of the machine shall not be less than 12 ft. It shall have a set of pivoting tandem bogey wheels at the front of the machine, and the rear wheels shall be arranged to travel in the track of the fresh cut pavement. The center of the grinding head shall be no further than 3 ft forward from the center of the back wheels. The equipment shall be of a size that will cut or plane at least 2 ft wide.

The equipment shall be capable of grinding the surface without causing spalls.

Where grinding is required, it will be performed across the entire 12.5-ft lane width.

b. The grinding operation shall proceed in a manner that produces a uniform finish surface. The Contractor shall establish positive means for removal of grinding residue. Grinding water and residue shall not be permitted to flow across adjacent test areas. The Contractor shall have sufficient collector and/or discharge hoses to ensure a majority of grinding residue is discharged outside the test section area.

c. The grinding process shall produce a pavement surface that is smooth and uniform in appearance with a longitudinal line type texture. The line type texture shall contain parallel longitudinal corrugations that present a narrow ridge corduroy type appearance. The peaks of the ridges shall not be more than 1/16 in. higher than the bottoms of the grooves.

d. The use of an asphalt milling machine as an alternative to diamond grinding equipment shall not be permitted.

7. Daily site cleanup of all trash and debris is required.

The Government will be responsible for the following:

1. Quality assurance operations for grade, limestone base material strength, subgrade material strength, and layer thicknesses (CBR as estimated using a dynamic cone penetrometer, density, moisture, and survey).

2. Quality assurance operations for PCC testing (air content, strength, consistency, and temperature).

3. Random HMA samples may be taken at the plant for specimen compaction and tested for laboratory air voids and tensile strength ratio (TSR). A portion of the same sample may be tested for TMD, aggregate gradation, and asphalt content. Randomly selected cores will be taken from the finished pavement mat and the longitudinal joint(s) and tested for density.

Random sampling shall be in accordance with procedures contained in ASTM D3665. The test results must demonstrate an in-place density of 92 to 96 percent of TMD. If test results fail to meet the required density, the test section shall be removed and replaced at no cost to ERDC.

4. Determination of final compacted HMA layer thickness will be performed by using rod and level and/or total station elevation measurement techniques.

PERIOD OF PERFORMANCE

Required Start Date: Two weeks after award Required Completion Date: One month after first day on government site Total Project Time: Six weeks from date of award

CONTRACTOR MANPOWER REPORTING

The Office of the Assistant Secretary of the Army (Manpower & Reserve Affairs) operates and maintains a secure Army data collection site where the contractor will report ALL contractor manpower (including subcontractor manpower) required for performance of this contract. The contractor is required to completely fill in all the information in the format using the following web address: https://contractormanpower.army.pentagon.mil. The required information includes:

(1) Contracting Office, Contracting Officer, Contracting Officer’s Technical Representative; (2) Contract number, including task and delivery order number; (3) Beginning and ending dates covered by reporting period; (4) Contractor name, address, phone number, e-mail address, identity of contractor employee entering data; (5) Estimated direct labor hours (including sub-contractors); (6) Estimated direct labor dollars paid this reporting period (including sub-contractors); (7) Total payments (including sub-contractors); (8) Predominant Federal Service Code (FSC) reflecting services provided by contractor (and separate predominant FSC for each sub-contractor if different); (9) Estimated data collection cost; (10) Organizational title associated with the Unit Identification Code (UIC) for the Army Requiring Activity (the Army Requiring Activity is responsible for providing the contractor with its UIC for the purposes of reporting this information); (11) Locations where contractor and sub-contractors perform the work (specified by zip code in the United States and nearest city, country, when in an overseas location, using standardized nomenclature provided on website); (12) Presence of deployment or contingency contract language: and (13) Number of contractor and sub-contractor employees deployed in theater this reporting period (by country). As part of its submission, the contractor will also provide the estimated total cost (if any) incurred to comply with this reporting requirement. Reporting period will be the period of performance not to exceed 12 months ending 30 September of each government fiscal year and must be reported by 31 October of each https://contractor/ calendar year. Contractors may use a direct XML data transfer to the database server or fill in the fields on the website. The XML direct transfer is a format for transferring files from a contractor’s systems to the secure web site without the need for separate data entries for each required data element at the web site. The specific formats for the XML direct transfer may be downloaded from the web site.

SAFETY

It is the responsibility of the contractor to ensure worker safety by informing the workers of any potential hazardous practices. Occupational Safety and Health Administration (OSHA) guidelines must be followed at all times for hazardous practices for handling and placing concrete. Workers are required to be informed of all hazardous materials and practices that may involve exposure to toxic materials in the workplace. Material Safety Data Sheets (MSDS) must be available to all workers at the work site.

Figure 1. Plan View of PCC Model to be Removed by the Contractor.

Figure 2. Photographs of Current PCC Model (west end to east end).

12.5 ft

285 ft

50 ft

N

15 ft

Looking west to east. Looking east to west.

Figure 3. Plan and Profile Views of PCC and HMA Model to be produced by the Contractor.

105 ft 180 ft

12.5 ft

15 ft

N

50 ft

15-in. PCC 8-in. HMA

8-in. crushed limestone silt

6-in. crushed limestone