317Stone Matrix Asphalt Concrete Placement

317.01 Description

This specification covers the furnishing, installation, and acceptance criteria for constructing stone matrix asphalt (SMA) concrete pavement. SMA shall be in accordance with these specifications and Section 315. 317.01

317.02 Materials

317.03 Composition of SMA Mixture

Composition of Stone Matrix Asphalt shall conform to Section 248.

317.04 Acceptance

Acceptance of Stone Matrix Asphalt shall conform to Section 248.

317.05 SMA Mixing Plant

317.06 Weather Restrictions

SMA mixture shall be placed only when the ambient and surface temperatures are 50 degrees F or above.

317.07 Placing and Finishing

For mixtures containing PG 64H-22 asphalt binder, the mixture temperature shall not be less than 300 degrees F in the truck or less than 290 degrees F immediately behind the screed. For mixtures containing PG 64E-22 asphalt binder, the mixture temperature in the truck and immediately behind the screed shall not be less than the minimum compaction temperature provided by the liquid asphalt supplier. The minimum mixture or compaction temperature immediately behind the screed when a warm mix asphalt additive or process is used to produce the SMA shall not be less than 200 degrees F . The Contractor shall be responsible for a continuous paving operation that provides for maintaining constant steady movement of the paver. If excessive stop and go of the paver is occurring, the Engineer 317.02 will stop production and laydown of the mixture until the Contractor has made satisfactory changes in the production, hauling, and placement operations resulting in a constant steady movement of the paver. The Contractor shall employ a Material Transfer Vehicle (MTV) during the placement of SMA mixes. The Contractor’ s paving operation shall have remixing capability in either the MTV or a paver-mounted hopper to produce a uniform nonsegregated mix of uniform temperature. The MTV and paver combi - nation shall have a minimum storage capacity of 15 tons. If equipment breaks down in the paving train, the Contractor shall notify the plant not to ship any more material and discontinue paving shall be discontinued once the material on-site has been placed.

317.08 Compaction

Immediately after the mixture has been spread and struck off, it shall be thoroughly and uniformly compacted by rolling. Rolling shall be accomplished with steel wheel roller(s) with a minimum weight of 10 tons. A minimum of three rollers shall be available at all times for compaction and/or finish rolling. The Contractor shall approach the use of vibratory rollers on SMA with caution to minimize coarse aggregate fracture/breakage in the aggregate skeleton of SMA mixes. If the Contractor elects to use a vibratory roller, the mat shall receive not more than three vibratory passes. The Contractor shall use the roller only on the highest frequency and lowest amplitude setting. It shall be the Contractor’ s responsibility to adjust the rolling procedures to provide the specified pave- ment density. Rollers shall move at a uniform speed. Rolling shall be continued until all roller marks are eliminated and the minimum density has been obtained. The Contractor shall monitor density during the compaction process by use of nuclear density gages to ensure that the minimum required compaction is being obtained. During the trial section, the Department will randomly select 3 plug or core locations to determine the in-place density according to VTM-22. The Contractor shall keep the wheels of the rollers properly moistened with water that has been mixed with very small quantities of detergent or other approved additives to prevent adhesion of the mixture to the rollers. For the purposes of evaluating and determining acceptance, each day’ s production shall be considered a lot unless the paving length is less than 3,000 linear feet or greater than 7,500 linear feet. When paving is less than 3,000 feet, that day’ s production amount shall be combined with the previous day’ s production or added to the next day’ s production to create a lot as described below. The standard size of a lot shall be 5,000 linear feet, with 1,000 foot sublots, of any pass 6 feet or greater for the specified thickness of the course. The Engineer may approve an increase in the lot size to 7,500 linear foot lots with 1,500 foot sublots when the normal daily production is in excess of 7,000 feet. Pav- ers traveling in echelon will be considered as two passes. When a partial lot occurs at the end of a day’ s production or upon completion of the project, the lot size shall be redefined as follows: • If the partial lot contains one or two sublots, the sublots will be added to the previous lot. • If the partial lot contains three or four sublots, the partial lot will be redefined to be an entire lot. The Contractor shall perform acceptance testing for density for each sublot by obtaining one sawed 4 inch by 4 inch specimen, or one 4-inch-diameter cores, at a single random test site specified by the 317.08 Engineer. Test sites shall not be located within 12 inches of the edge of any application width for surface and intermediate mixes. • The sub-lot site shall be marked as described in VTM-76. • The bulk specific gravity of the cores shall be determined in accordance with VTM-6. • The density of the cores shall be determined in accordance with VTM-22. The Contractor shall bulk the cores or plugs in the presence of the Engineer. The cores or plugs may be bulked on the project site. Sublot test sites shall be numbered sequentially per lot, marked on the pavement, filled with the paving mixture, and compacted prior to completion of each day’ s production. The payment for lot density will be in accordance with the following schedule: Payment Schedule % Density Achieved % of Payment More than 98.0 97 94.0 to 98.0 100 92.0 to 93.9 85 90.0 to 91.9 65 Less than 90.0 Remove and replace

317.09 Trial Section

The Engineer will require the Contractor to construct a trial section(s) for evaluation at least 1 week, but not more than 30 days, prior to the start of roadway construction at the start of production of a SMA mix not placed the previous year on a state roadway. The trial section shall be a maximum of 300 tons, shall be constructed at a site designated in the contract or proposed by the Contractor and approved by the Engineer. The Department will use the trial section to evaluate the mixing plant process control, mixture draindown characteristics, placement procedures, SMA surface appearance, and compaction patterns and to calibrate the nuclear density device. Additionally, the Department will calculate the percentage of flat and elongated particles in the SMA material produced for the trial section according to VTM-121 and compare the results to the maximum limits specified in the Coarse Aggregate Table in Section 248.02(a). The Engineer will require a passing flat and elongated sample for acceptance of the trial section. During the trial section(s), the Engineer will randomly select 3 plugs or cores locations to determine the in-place density according to VTM-22. Payment for density will be in accordance with the Payment Schedule listed in Sec. 317.08. The Contractor shall remove and replace failing trial sections based on the following criteria. The En - gineer will deem a trial section to have failed if the V oids In Total Mix (VTM) is less than 1.0 percent or exceeds 5.0 percent; if the V oids In Coarse Aggregate (VCA) of the mix exceeds the VCA of the dry rodded condition; if the field density is less than 90.0 percent of the maximum theoretical density; or if excessive flushing/bleeding occurs in the wheel paths. Payment for the trial section shall be as described in the previous paragraph. The Contractor shall be responsible for the cost for removing the failed trial section. Payment for replacement of the trial section shall be in accordance with the previous paragraph. 317.08