248—STONE MATRIX ASPHALT CONCRETE

VA · 2020 Standard SpecificationsBook pages 334–340View official source ↗

306(a) Permanent Devices with ASTM D4956 Types IX or XI sheeting: 12-year warranty with 7 years being 100% full replacement covering all material and labor costs associated with fabrication and installation of the sign or device and the ﬁnal 5 years being 100% sheeting material replacement cost.

b.Permanent Devices with ASTM D4957 Types IV sheeting: 10-year warranty with 7 years being 100% full replacement covering all material and labor costs associated with fabrication and instal - lation of the sign or device and the ﬁnal 3 years being 100% sheeting material replacement cost.

c.Temporary rigid signs, rollup signs, and other temporary devices: 3-year full replacement covering all material and labor costs associated with fabrication of the sign or device. SECTION 248—STONE MATRIX ASPHALT CONCRETE

248.01 Description

These speciﬁcations cover the materials used to produce stone matrix asphalt (SMA) concrete pavement. SMA shall be in accordance with this speciﬁcation and Section 211. SMA consists of a combination of coarse aggregate, ﬁne aggregate, mineral ﬁller, ﬁber additives, and liquid asphalt binder mechanically mixed in a plant to produce a stable gap-graded asphalt concrete paving mixture.

248.02 Materials

a.Coarse Aggregate: Coarse aggregate shall conform to the following requirements when tested in accordance with the speciﬁed tests: Requirement Test Value Los Angeles Abrasion AASHTO T96 40% max. Flat and Elongated Particles: Measured on No. 4 retained, VTM-121 3 to 1 20% max. 5 to 1 5% max. Magnesium Sulfate Soundness Loss, 5 cycles AASHTO T104 15% max. Particles retained on No. 4 sieve shall have at least ASTM D5821 1 fractured face 100% min. 2 fractured faces 90% min. Absorption AASHTO T85 2% max. Except for the determination of ﬂat and elongated particles {Section 248.02(a)}, the aggregate properties speciﬁed are for each stockpile of coarse aggregate material designated on the job mix form (Form TL-127). The material contained in each stockpile shall meet the minimum or maximum criteria speciﬁed. For ﬂat and elongated particles, these values are based on the mathematical blend of the coarse aggregate material designated on the job mix form (TL-127). During production, these values are based on the SMA material sampled during the acceptance process (QC testing). SMA must contain two or more coarse aggregate sizes. At least two of the aggregate sizes must comprise a minimum of 10% of the total mix composition each. At least one cold feed bin shall be used for each aggregate size.247.03 307The Engineer will not permit the use of slag in the job mix formula. At the Engineer’ s discretion, mixes containing Reclaimed Asphalt Pavement (RAP) may be tested by VDOT for aggregate breakdown during lab compaction in accordance with VTM-99. If the per - cent of the total mix passing the No. 4 sieve increases by more than 10 percent after being compact - ed to Ndesign, then the RAP component shall be changed or the Engineer will discontinue allowing its use in the mix.

b.Fine Aggregate: Virgin ﬁne aggregates shall consist of a blend of 100 percent crushed aggregate. If RAP is being used as a component in SMA then the portion of the ﬁnal SMA blend passing the No. 8 sieve shall have a minimum Fine Aggregate Angularity (FAA) value of 45 percent as deter - mined in accordance with AASHTO T304 (Method A). The magnesium sulfate soundness loss in 5 cycles shall not exceed 20 percent. In addition, the liquid limit shall not exceed 25 as determined in accordance with AASHTO T89.

c.Asphalt Binder: Asphalt binders shall be performance graded binder PG 64H-22 or polymer modiﬁed binder PG 64E-22 conforming to the mix designation (E) as speciﬁed by the Department. The supplier shall certify to the Department that the binder complies with the requirements for all properties of the grade as speciﬁed in AASHTO M332 Table 1 for performance-graded asphalt binder. This certiﬁcation shall be based on testing performed on samples of binder provided to the Contractor for incorporation into the mixture. The Engineer will not allow certiﬁcation based on testing performed on laboratory-produced binders. The Contractor shall submit to the Engineer for Department review the source, formulation, and PG grading of the binder at least 15 days prior to the production of the SMA mixture. The Department will test samples taken from storage at the hot-mix asphalt plant during mixture production at the Engineer’ s direction to determine the binder PG grade. The Contractor shall be responsible for obtaining the sample of binder when requested by the Engineer. If the Department determines the binder does not comply with the requirements of the speciﬁed PG grade, production will be stopped until further testing indicates that the problem has been corrected.

d.Mineral Filler: Mineral ﬁller shall consist of ﬁnely divided mineral matter such as rock or limestone dust or other suitable material. The Engineer will not permit the use of hydrated lime and ﬂy ash. The supplier may blend up to two mineral ﬁllers to comply with the mineral ﬁller requirements. Mineral ﬁller shall conform to Section 201 with the following modiﬁcations. The mineral ﬁller or mineral ﬁller blend used in surface and intermediate SMA shall have a minimum of 55 percent passing the No. 200 sieve. At the time of use, it shall be sufﬁciently dry to ﬂow freely and be essentially free from agglomerations.

e.Fiber Additive: The supplier shall use cellulose ﬁber in either loose or pelletized form. The minimum dosage rate for cellulose is 0.3 percent by weight of the total mixture. The Department may require the percentage of ﬁber additive to be increased during production if visual inspection or draindown testing on plant-produced material indicates that draindown in excess of 0.3 percent by weight of the mixture is occurring as determined in accordance with VTM-100. Allowable tolerances of ﬁber dosage shall be ±10 percent of the required ﬁber weight. NOTE: When using pelletized ﬁber, the dosage rate shall be adjusted to comply with the speciﬁed minimum dosage rates for cellulose ﬁber. Pelletized ﬁber consists of cellulose ﬁber and a binder. The speciﬁed minimum dosage rates are based on ﬁber content only. Therefore, the amount of pelletized ﬁber added shall typically be higher than for loose ﬁber.248.02 308The Engineer will accept ﬁbers based on the manufacturer’ s certiﬁcation.

f.Antistripping Additive: An antistripping additive shall be used in all stone matrix asphalt mixes. It may be hydrated lime or a chemical additive from the Materials Division’ s Approved Products List No. 7, or a combination of both. The approved chemical additive shall be added at a rate of not less than 0.30 percent by weight of the total asphalt content of the mixture. The mixture shall produce a tensile strength ratio (TSR) of not less than 0.80 for the design and production tests. The TSR shall be determined in accordance with AASHTO T283, including a freeze-thaw cycle (4-inch specimens compacted with a Marshall Hammer or 3.5 by 6-inch speci - mens when compacted with a gyratory compactor); except that the 16-hour curing time requirement and the 72 to 96-hour storage period will not be enforced by the Department. Design tests shall use the same materials that are to be used in the production mix and shall be conducted in a laboratory approved by the Department. When a chemical additive is used, it shall be added to the asphalt cement prior to the introduction of the asphalt cement into the mix. Any chemical additive or particular concentration of chemical 248.02 TABLE II-23 Cellulose Fiber Properties Sieve Analysis Requirement Method A: Alpine Sieve1 Analysis Fiber Length: 0.25 inch max. Passing No. 100 Sieve 70% (±10%) Method B: Mesh Screen2 Analysis Fiber Length: 0.25 inch max. Passing No. 20 Sieve 85% (±10%) No. 40 Sieve 65% (±10%) No. 140 Sieve 30% (±10%) Ash Content3 18% (±5%) non-volatile pH4 7.5 (±1.0) Oil Absorption5 5.0 (±1.0) (times ﬁber weight) Moisture Content6 <5% 1 Method A: Alpine Sieve Analysis. Performed using an Alpine Air Jet Sieve (Type 200 LS). A representative 5-gram sample of ﬁber is sieved for 14 minutes at a controlled vacuum of 22 inches (±3 inches) of water. The portion remaining on the screen is weighed. 2 Method B: Mesh Screen Analysis. This test is performed using standard Nos. 20, 40, 60, 80, 100, and 140 sieves, nylon brushes, and a shaker. A representative 10-gram sample of ﬁber is sieved, using a shaker and two nylon brushes on each screen. The amount retained on each sieve is weighed and the percentage passing calculated. 3 Ash Content: A representative 2- to 3-gram sample of ﬁber is placed in a tared crucible and heated between 1100 and 1200 degrees F for not less than 2 hours. The crucible and ash are cooled in a desiccator and reweighed. 4 pH Test: Five grams of ﬁber is added to 3.5 ounces of distilled water, stirred, and allowed to set for 30 minutes. The pH is determined with a probe calibrated with a pH 7.0 buffer. 5 Oil Absorption Test: Five grams of ﬁber is accurately weighed and suspended in an excess of mineral spirits for not less than 5 minutes to ensure total saturation. It is then placed in a screen mesh strainer (with a hole size of approx - imately 0.5 square millimeter), and shaken on a wrist action shaker for 10 minutes (approximately 1 ¼-inch motion at 20 shakes/minute). The shaken mass is then transferred without touching to a tared container and weighed. Results are reported as the amount (number or times its own weight) the ﬁbers are able to absorb. 6 Moisture Content: Ten grams of ﬁber is weighed and placed in a 250 degree F forced air oven for 2 hours. The sample is then reweighed immediately upon removal from the oven. 309additive found to be harmful to the asphalt material or that changes the original asphalt binder performance grade (PG) shall not be used.

g.Hydrated lime shall conform to ASTM C977. Hydrated lime shall be added at a rate of not less than 1 percent by weight of the total dry aggregate. A separate bin or tank and feeder system shall be provided to store and accurately proportion the dry or slurried lime into the aggregate. The lime and aggregate shall be mixed by pugmill or other Department approved means to achieve a uniform lime coating of the aggregate prior to entering the drier. If lime is added in dry form, the aggregate shall contain at least 3 percent free moisture. The Department will not permit the stockpiling of lime treated aggregate. The feeder system shall be controlled by a proportioning device, which shall be accurate to within ±10 percent of the speciﬁed amount. The proportioning device shall have a convenient and accurate means of calibration. A ﬂow indicator or sensor shall be provided with the proportioning device and interlocked with the plant controls, aggregate feed or weigh system, such that production of the mixture shall be consistently maintained and, if there is a stoppage of the lime feed, interrupted. The method of introducing and mixing the lime and aggregate shall be subject to approval by the Engineer prior to beginning production.

h.RAP: The Contractor or his supplier may use Reclaimed Asphalt Pavement (RAP) material as a component material of SMA mixtures provided it conforms to the following:

1.SMA surface and intermediate mixtures containing RAP shall use the PG grade of asphalt cement designated by the mix speciﬁed on the plans or in the proposal, e.g. an SMA-12.5 (64E-22).

2.The ﬁnal asphalt mixture shall conform to the type speciﬁed.

3.During the production process, RAP material shall not be allowed to contact open ﬂame.

4.The Contractor or his supplier shall handle, haul, and store the RAP material in a manner that will minimize contamination. Further, the material shall be stockpiled and used in such manner that variable asphalt contents and asphalt penetration values will not adversely affect the consistency of the mixture.

248.03 Composition of SMA Mixture

The Contractor or his supplier shall design and test the SMA mixture using a gyratory compactor. The designated mixture shall conform to Table II-24 and Table II-25. One percent hydrated lime will be required as an antistripping additive. An alternative antistripping additive can be used only with the Engineer’ s permission. Draindown testing shall be conducted in accordance with VTM-100. RAP percentages shall conform to Table II-26.248.03 310248.04—Acceptance The Engineer will consider a lot to be acceptable for gradation and asphalt content if the mean of the test results obtained is within the tolerance allowed from the job-mix formula. The production tolerances for the control sieves and asphalt content shall be as follows:248.03 TABLE II-24 SMA Design Range Percentage by Weight Passing Square Mesh Sieves (in) Type No . 1 3/4 1/2 3/8 No. 4 No. 8 No. 30 No. 200(See Note) Surface Mixes SMA 12.5 100 83-93 80 max 22-28 16-24 15-20 9-11 SMA 9.5 100 90-100 65-75 25-32 15-25 9-11 Intermediate Mixes SMA 19.0 100 85-95 50-60 30-45 16-24 12-16 8-10 Note: The required PG binder will be shown in parentheses as part of the mix type on the plans or in the proposal, e.g., SMA 12.5 (76-22). TABLE II-25 SMA Mixture Requirements VCA VMA VMA Design and AC Mix VTM1 Design Production Production2 (Min . Draindown Design Specimen Type (%) (Min . %) (Min . %) (%) %) (%) Gyrations Height3 SMA 9.5 2.0-4.0 18.0 17.0 <VCA DRC 6.3 0.3 max 75 115 SMA 12.5 2.0-4.0 18.0 17.0 <VCA DRC 6.3 0.3 max 75 115 SMA 19.0 2.0-4.0 17.0 16.0 <VCA DRC 5.5 0.3 max 75 115 1 Asphalt content shall be selected at the midpoint of the VTM range but shall not be less than the minimum speciﬁed. 2 The voids in coarse aggregates (VCA) of the dry rodded condition (DRC) and mix shall be determined in accor- dance with VTM-99. 3 Specimen height after compaction shall be between 4.25 and 4.75 inches. 4 The ﬁnes-effective asphalt ratio shall be 1.2-2.0 Note: The SUPERPA VE gyratory compactor (SGC) shall be from the Department’ s approved list maintained by the Department’ s Materials Division. Gyratory procedures shall be performed in accordance with VTM-99. Calculations for volumetrics shall be performed in accordance with VTM-57 and VTM-58 using 6-inch specimens. TABLE II-26 Speciﬁed Performance Grade of Asphalt and Use of RAP Mix Type & PG Allowable RAP Percentage in Mix SMA-9.5 (64H-22), SMA-12.5 (64H-22) & SMA-19.0(64H-22) 0.0 to 20.0 SMA-9.5 (64E-22), SMA-12.5 (64E-22) & SMA-19.0 (64E-22) 0.0 to 15.0 311Process Tolerance The production tolerance for the specimen height after compaction is 110mm to 120mm. The Contractor shall check and report the VCA of the mix during production for each gyratory sample. If the VCA of the mix exceeds the VCA of the DRC, the Contractor shall stop production and notify the Engineer. Production shall not resume until the Contractor has taken corrective action and the Engineer has accepted the Contractor’ s means of correction. The Contractor shall check and report the percentage of ﬂat and elongated particles (F&E) in the coarse aggregates of the mix design during production. Two of eight sub-lots from the ﬁrst lot of material shall be selected for F&E veriﬁcation when the Contractor samples the SMA material for ac - ceptance (gradation and AC content). F&E testing shall be performed on the coarse aggregate material retained on the #4 sieve, in accordance with VTM-121, after the gradation is performed. If passing results are obtained on each sample in the ﬁrst lot, then F&E testing shall be performed on a frequency of every second lot of material produced (i.e., Lots 3, 5, 7, etc.) by randomly selecting two sub-lots. If the F&E of the mix exceeds the speciﬁed limits, the Contractor shall stop production and notify the Engineer. Production shall not resume until the Contractor has taken corrective action and the Engi - neer has accepted the Contractor’ s means of correction. Once production has resumed, the Contractor shall determine the F&E of the mix for two consecutive lots by randomly selecting two sub-lots per lot. If passing results are obtained for these two lots, then the F&E testing frequency shall return to every second lot of material produced. If the Department determines that the mixture being produced does not conform to the approved job-mix formula and the volumetric properties in Table II-25 based on the Department or the Contractor’ s test results, the Contractor shall immediately make corrections to bring the mixture into conformance with the approved job-mix formula or cease paving with that mixture. The Engineer will limit subsequent paving operations using either a revised or another job-mix formula, which has not been veriﬁed as described herein, to a test run of 300 tons maximum if such material is to be placed in Department project work. The Engineer will not allow any further paving for the Department using that speciﬁc mixture until the acceptability of the mixture being produced has received the Engi - neer’ s approval based on the 300-ton constraint.

248.05 SMA Mixing Plant

Plants used for the preparation of the SMA mixture shall conform to the following:248.05 Tolerance on Each Laboratory Sieve and Asphalt Content: Percent Plus and Minus No. Top 3/4” 1/2” 3/8” No. 4 No. 8 No. 30 No. 200 A.C. Tests Size 1 0.0 8.0 8.0 8.0 6.0 6.0 6.0 4.0 0.60 2 0.0 5.7 5.7 5.7 4.3 4.3 4.3 2.8 0.43 3 0.0 4.4 4.4 4.4 3.3 3.3 3.3 2.2 0.33 4 0.0 4.0 4.0 4.0 3.0 3.0 3.0 2.0 0.30 5 0.0 3.6 3.6 3.6 2.7 2.7 2.7 1.8 0.27 6 0.0 3.3 3.3 3.3 2.4 2.4 2.4 1.6 0.24 7 0.0 3.0 3.0 3.0 2.3 2.3 2.3 1.5 0.23 8 0.0 2.8 2.8 2.8 2.1 2.1 2.1 1.4 0.21 12 0.0 2.3 2.3 2.3 1.7 1.7 1.7 1.2 0.17 312(a) Handling of Mineral Filler: Adequate dry storage shall be provided for the mineral ﬁller that will, at a minimum, consist of a waterproof cover that shall completely cover the stockpile at all times. Provisions shall be made for metering of the ﬁller into the mixture uniformly and in the desired quantities. In a batch plant, mineral ﬁller shall be added directly into the weigh hopper. In a drum plant, mineral ﬁller shall be added directly onto the cold feed belt. Equip¬ment shall be capable of accurately and uniformly metering the large amounts of mineral ﬁller up to 25 percent of the total mix.

b.Fiber Addition: Adequate dry storage shall be provided for the ﬁber additive. Provisions shall be made for accurately and uniformly metering ﬁber into the mixture at plus or minus 10 percent of the desired quantities. Introduction of loose or pelletized ﬁber shall require a separate system that can accurately proportion, by weight, the required quantity of ﬁber in such a manner as to ensure consistent, uniform blending into the mixture at all rates of production and batch sizes. This supply system shall be interlocked with the other feeding devices of the plant system. Sensing devices shall provide for interruption of mixture production if the introduction of ﬁber fails. Batch Plant: Loose ﬁber or pelletized ﬁber shall be added through a separate inlet directly into the weigh hopper above the pugmill. The addition of ﬁber shall be timed to occur during the hot aggregate charging of the hopper. Adequate dry mixing time is required to ensure proper blending of the aggregate and ﬁber stabilizer. Therefore, dry mixing time shall typically be increased 5 to 15 seconds. Wet mixing time shall typically be increased at least 5 seconds for cellulose ﬁbers to ensure adequate blending with the asphalt cement. When ﬁber is used, the ﬁber supply system shall include low level and no ﬂow indicators, and a printout of the date, time, and net batch weight of ﬁber. Drum Mix Plant: When ﬁber is used, the ﬁbers shall be added in such a manner as not to be en - trained into the exhaust gases of the drum plant. The ﬁber supply system shall include low level and no ﬂow indicators, and a printout of status of feed rate in pounds per minute. When pelletized ﬁbers are used, they shall be added directly into the drum mixer through the RAP inlet or a specialized ﬁber inlet. Operation of the drum mixer shall be such as to ensure complete blending of the pelletized ﬁber into the mix.

c.Hot Mixture Storage: When the Contractor does not immediately haul and place the hot mixture on the project, it, the Contractor shall provide suitable bins for storage of the hot mixture. Such bins shall be either surge bins to balance production capacity with hauling and placing capacity or storage bins that are heated and insulated and that have a controlled atmosphere around the mixture. The Engineer will impose limitations on the holding times based on laboratory tests of the stored mixture. In no case shall the SMA mixture be kept in storage more than 8 hours.

d.Mixing Temperature: The recommended plant mixing temperatures for PG 64H-22 should be 315 to 340 degrees F and at no time shall the temperature exceed 350 degrees F . For PG 64E-22, the plant mixing temperatures shall be within the limits of the asphalt supplier’ s recommendations.248.05 313SECTION 249—FLOW ABLE BACKFILL

249.01 Description

These speciﬁcations cover materials, design criteria, and mixing and testing procedures for ﬂowable backﬁll used in applications where modiﬁed liquid or plastic concrete is required for backﬁlling pipe installations and plugging abandoned pipe lines, culverts, and conduits.

249.02 Materials

a.Hydraulic Cement shall conform to Section 214.

b.Fly Ash shall conform to Section 241.02(a).

c.Water shall conform to Section 216, except that wash water as described in Section 216.02 may comprise the total mix water.

d.Aggregates shall conform to Sections 202 and 203 with a combined gradation as determined by the Contractor.

e.Admixtures shall conform to Section 215.

f.Granulated Iron Blast Furnace Slag shall conform to Section 215.

249.03 Mix Design

The Contractor shall provide the appropriate mix design for the ﬂowable backﬁll application. Flowable backﬁll shall have a design compressive strength of 30 to 200 pounds per square inch when used as back - ﬁll material in pipe installations or in other uses at locations as designated on the plans. Flowable backﬁll shall have a design compressive strength of 30 to 1200 pounds per square inch when used as backﬁll material for plugging pipes and culverts designated for abandonment as shown on the plans. The design compressive strength requirement shall be at 28 days when tested in accordance with ASTM D 4832. Mix design shall result in a ﬂuid product having no less than an 8-inch slump at the time of placement. The Contractor shall submit a mix design verifying compliance with 28 day compressive strength requirements supported by laboratory test data to the Engineer for review. The Contractor must have the Engineer’ s acceptance of the Contractor’ s mix design and test data prior to placement of the ﬂowable backﬁll. SECTION 250 - CARBON FIBER MESH

250.01 Description

These speciﬁcations cover carbon ﬁber mesh used along with EP-7 epoxy to seal joints in between box beam bridges and other bridge joints.250.01

Source: Virginia Road and Bridge Specifications, 2020 Edition. Pages 334–340 of 1,065.

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247 —REFLECTIVE SHEETING

249 —FLOWABLE BACKFILL