Article 1 — Description
Construct a foundation course composed of flexible base.
Article 2 — Materials
Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. Notify the Engineer of the proposed material sources and of changes to material sources. The Engineer may sample and test project materials at any time before compaction throughout the duration of the project to assure specification compliance.
2.1 Aggregate . Furnish aggregate of the type and grade shown on the plans and meeting the requirements
shown in Table 1. Each source must meet Table 1 requirements for liquid limit, plasticity index, and wet ball mill for the grade specified. Do not use additives, such as but not limited to lime, cement, or fly ash to modify aggregates to meet the requirements of Table 1, unless shown on the plans. Unless otherwise shown on the plans, the unconfined compressive strength is waived when the flexible base material meets the #200 sieve requirement. When the #200 sieve requirement does not meet the specification in Table 1, the unconfined compressive strength is required. Table 1 Material Requirements Property Test Method Grade 1 –23 Grade 3 Grade 4 Grade 5 Master gradation sieve size (cumulative % retained) Tex-110-E As shown on the plans 2-1/2” 0 0 0 1-3/4” 0–10 0–10 0–5 7/8” 10–35 – 10–35 3/8” 30–65 – 35–65 #4 45–75 45–75 45–75 #40 65–90 50–85 70–90 #2001, 2 85–95 – – Liquid limit, % Max Tex-104-E 40 40 35 Plasticity index, Max Tex-106-E 10 12 10 Plasticity index, Min As shown on the plans As shown on the plans As shown on the plans Wet ball mill, % Max Tex-116-E 40 – 40 Wet ball mill, % Max increase passing the #40 sieve 20 – 20 Min compressive strength2, psi Tex-117-E lateral pressure 0 psi 35 – – lateral pressure 3 psi – – 90 lateral pressure 15 psi 175 – 175 1. The #200 sieve test is only required to meet the waiver of the unconfined compressive strength requirement. The #200 sieve test requirement is only applicable to stockpile samples from 2. Compressive strength and #200 sieve test requirements are waived when the flexible base is mixed with or without existing material and treated with cement, emulsion, foamed asphalt, or lime, unless otherwise shown on the plans. 3. Grade 3 may be substituted for Grade 1–2 or Grade 5 when the flexible base is mixed with or without existing material and treated with cement, emulsion, foamed asphalt, or lime, as approved. Grade 3 flexible base must meet the wet ball mill requirements of Grade 1 –2 or Grade 5 as applicable. 165 2.1.1. Material Tolerances. The Engineer may accept material if no more than one of the five most recent gradation tests has an individual sieve outside the specified limits of the gradation. This allowance does not apply to the #200 sieve requirement. The Engineer may accept material if no more than one of the five most recent liquid limit or plasticity index tests is outside the specified limit. No single failing liquid limit or plasticity index test may exceed the allowable limit by more than 2 percentage points.
2.1.2 Material Types. Do not use fillers or binders unless approved. Furnish the type shown on the plans in accordance with the following.
2.1.2.1. Type A . Crushed stone produced and graded from oversize quarried aggregate that originates from a single, naturally occurring source. Do not use gravel or multiple s ources. 2.1.2.2. Type B . Crushed or uncrushed gravel. Blending of two or more sources is allowed. 2.1.2.3. Type C . Crushed gravel with a minimum of 60% of the particles retained on a No. 4 sieve with two or more crushed faces as determined in accordance with Tex -460-A , Part I. Blending of two or more sources is allowed. 2.1.2.4. Type D . Type A material or crushed concrete. Crushed concrete containing gravel will be considered Type D material. Crushed concrete must meet the requirements of Section 247.2.1.2.6., “Recycled Material,” and be managed in a way to provide for uniform quality. The Engineer may require separate dedicated stockpiles t o verify compliance. 2.1.2.5. Type E . Caliche, iron ore, or as otherwise shown on the plans. 2.1.2.6. Recycled Material . Reclaimed asphalt pavement (RAP) and other recycled materials may be used when shown on the plans. Request approval to blend two or more sources of recycled materials. When RAP is allowed, do not exceed 20% RAP by weight, unless otherwise shown on the plans. The percentage limitations for other recycled materials will be as shown on the plans. Provide recycled materials, other than RAP, that have a maximum sulfate content of 3,000 ppm when tested in accordance with Tex -145-E . Certify compliance with DMS -11000 , “Evaluating and Using Nonhazardous Recyclable Materials Guidelines.” In addition, recycled materials must be free of reinforcing steel and other objectionable material and have at most 1.5% deleterious material when tested in accordance with Tex-413-A . The liquid limit, plasticity index, wet ball mill, and compressive strength for all recycled materials are waived. When using RAP, crush RAP so that 100% passes the 2- in. sieve and does not exceed a maximum percent loss from decantation of 5.0% when tested in accordance with Tex-406-A . Test RAP without removing the asphalt. The final product must meet the requirements shown in Table 1 for the grade spec ified except when the Department requires a specific amount of Department -furnished RAP be added to the blend, unless otherwise shown on the plans. The Contractor is responsible for uniformly blending the recycled material with the flexible base material t o build a stockpile to meet the percentages required. Any Contractor -furnished surplus of recycled materials will remain the property of the Contractor. Remove Contractor -owned recycled materials from the project and dispose of them in accordance with federal, state, and local regulations before project acceptance.
2.2 Water . Furnish water free of industrial wastes and other objectionable matter.
2.3 Material Sources. Expose the vertical faces of all strata of material proposed for use when non- commercial
sources are used. Secure and process the material by successive vertical cuts extending through all exposed strata, when directed.
2.4 Stockpile Approval . Stockpile is approved when the Engineer’s test results meet the material requirements
show n in Table 1. 166 2.4.1. Sampling . The Contractor and the Engineer will sample flexible base from completed stockpiles in accordance with Tex -100-E . Personnel conducting sampling must be certified by the Department -approved soils and base certification program. Sampling stockpiles may be located at the production site or at the project location. The Contractor will witness the Engineer’s sampling and sample the stockpile for their own testing, and label as deemed necessary. Sample the stockpile for the Engineer when shown on the plans. When the Contractor samples the stockpile for the Engineer, the Engineer must witness the sampling of material designated for the Engineer and the Materials and Tests Division (MTD). The Engineer will label their sampling containers as “Engineer” and “MTD,” or as deemed necessary. The Engineer will take immediate possession of the sample containers for the Engineer and MTD. The Engineer will maintain custody of the samples until all testing and reporting are completed.
2.4.2 Referee Testi ng. Referee testing is applicable for stockpile testing only. MTD is the referee laboratory. MTD
may designate a laboratory from the Department’s MPL for Commercial Laboratories Approved for Flexible Base Referee Requests as the referee laboratory as deemed necessary. The designated laboratory cannot be performing any testing under this Item for the Engineer or Contractor. The Contractor may request referee testing when the Engineer’s test results fail to meet any of the material requirements shown in Table 1 and the Contractor’s sample from Section 2.4.1., “Sampling,” for the same failing Department test, passes. The tests must be performed by a laboratory listed on the Department’s MPL for Commercial Laboratories Approved for Flexible Base Referee Requests. Submit the request by email within 5 working days after receiving failing test results from the Engineer. Include completed test reports passing the applicable requirements shown in Table 1 in the email. Record and submit completed test reports electronically on Department -provided templates in their original format meeting the applicable material requirements shown in Table 1. Use Department -provided templates to record and calculate all test data. The Engineer and the Contractor will provide any available test results to the other party when requested.
Article 3 — Equipment
Provide machinery, tools, and equipment necessary for proper execution of the work.
3.1 Rollers. Provide rollers in accordance with Item 210, “Rolling.” Provide proof rollers in accordance with
Item 216, “Proof Rolling,” when required.
3.2 Inertial Profiler . When ride quality measurement is required, provide a high- speed or lightweight inertial
profiler certified at the Texas A&M Transportation Institute. Provide equipment certification documentation. Display a current decal on the equipment indicating the certification expiration date.
Article 4 — Construction
Construct each layer uniformly, free of loose or segregated areas, and with the required density and moisture content. Provide a smooth surface that conforms to the typical sections, lines, and grades shown on the plans or as directed. Stockpile base material temporarily at an approved location before delivery to the roadway. Build stockpiles in layers no greater than 2 ft. thick. Stockpiles must have a total height between 10 and 16 ft. unless otherwise approved. After construction and acceptance of the stockpile in accordance with Section 247.2.4., “Stockpile Approval,” loading from the stockpile for delivery is allowed. Load by making successive vertical cuts through the entire depth of the stockpile. 167 Do not add or remove material from temporary stockpiles that require sampling and testing before delivery, unless otherwise approved. Charges for additional sampling and testing required as a result of adding or removing material will be deducted from the Contractor’s estimates. Haul approved flexible base in clean trucks. Deliver the required quantity to each 100- ft. station or designated stockpile site as shown on the plans. Prepare stockpile sites as directed. When delivery is to the 100-ft. station, manipulate in conformance with the applicable Items.
4.1 Preparation of Subgrade or Existing Base . Remove or scarify existing asphalt concrete pavement in
accordance with Item 105, “Removing Treated and Untreated Base and Asphalt Pavement,” when shown on the plans or as directed. Shape the subgrade or existing base to conform to the typical sections shown on the plans or as directed. When new base is required to be mixed with existing base, deliver, place, and spread the new flexible base in the required amount per station. Manipulate and thoroughly mix the new base with existing material to provide a uniform mixture to the specified depth before shaping. Proof roll the roadbed in accordance with Item 216 before pulverizing or scarifying when shown on the plans or directed. Correct soft spots as directed.
4.2 Placing . Spread and shape flexible base into a uniform layer using an approved spreader the same day as
delivered unless otherwise approved. Construct layers to the thickness shown on the plans. Maintain the shape of the course. Control dust by sprinkling, as directed. Correct or replace segregated areas as directed at no additional expense to the Department. Place successive base courses and finish courses using the same construction methods required for the first course.
4.3 Compaction. Compact using density control unless otherwise shown on the plans. Multiple lifts are permitted when shown on the plans or approved. Bring each layer to the moisture content directed. When
necessary, sprinkle the material in accordance with Item 204, “Sprinkling.” Maintain moisture during compaction within ±2.0% of the optimum moisture content as determined in accordance with Tex -113-E . Begin rolling longitudinally at the sides and proceed toward the center, overlapping on successive trips by at least 1/2 the width of the roller unit. Begin rolling at the low side and progress toward the high side on superelevated curves. Offset alternating trips of the roller. Operate rollers at a speed between 2 and 6 mph as directed. Rework, recompact, and refinish material that fails to meet or that loses required moisture, density , stability, or finish requirements before the next course is placed or the project is accepted. Continue work until specification requirements are met. Perform the work at no additional expense to the Department. Before final acceptance, the Engineer will select the locations of tests and measure the flexible base depth in accordance with Tex -140-E . Correct areas deficient by more than 1/2 in. in thickness by scarifying, adding material as required, reshaping, recompacting, and refinishing at the Contractor’s expense.
4.3.1 Ordinary Compaction. Roll using approved compaction equipment as directed. Correct irregularities, depressions, and weak spots immediately by scarifying the areas affected, adding or removing approved
material as required, reshaping, and recompacting.
4.3.2 Density and Moisture Control . Compact to a minimum of 100% of the maximum dry density and within
±2.0% of the optimum moisture content as determined in accordance with Tex -113-E , unless otherwise shown on the plans. Provide the Engineer with the beginning and ending station numbers of the area completed for testing. The Engineer will determine roadway density and moisture content of completed sections in accordance with Tex-115-E , Part I. The Engineer will determine random locations for testing in accordance with Tex-115-E , Part IV. Do not achieve density by drying the material after compaction. 168 When the density is less than 100% of the maximum dry density, the Engineer may perform additional testing to determine the extent of the area to correct. The Engineer may accept the section if no more than one of the five most recent density tests is below the specified density and the failing test is no more than 3 pcf below the specified density.
4.3.3 Miscellaneous and Small Areas . Miscellaneous areas are those that typically involve handwork or
discontinuous paving operations, such as temporary detours, driveways, mailbox turnouts, crossovers, gores, spot level -up areas, and other similar areas. Miscellaneous and small areas are not subject to density testing but may be tested as directed.
4.4 Finishing. After c ompleting compaction, clip, skin, or tight -blade the surface using a maintainer or subgrade
trimmer to a depth of approximately 1/4 in. Remove loosened material and dispose of it at an approved location. Seal the clipped surface immediately by rolling using a pneumatic tire roller until a smooth surface is attained. Add small increments of water as needed during rolling. Shape and maintain the course and surface in conformity with the typical sections, lines, and grades as shown on the plans or as directed. Correct grade deviations greater than 1/4 in. in 16 ft. measured longitudinally. Correct grade deviations greater than 1/4 in. over the entire width of the cross -section in areas where surfacing is to be placed. Correct by loosening and adding or removing material. Reshape and recompact in accordance with
4.5 Curing. Cure the finished section until the moisture content is at least 2 percentage points below optimum or
as directed before applying the next successive course or prime coat.
4.6 Ride Quality. Measurement of ride quality only applies to the final travel lanes that receive a one- or
two-course surface treatment for the final riding surface, unless otherwise shown on the plans. Measure the ride quality of the base course either before or after the application of the prime coat, as directed, and before placement of the surface treatment. Use a certified profiler operator listed on the Department’s MPL. When requested, furnish the Engineer with documentation for the person certified to operate the profiler. Provide all profile data to the Engineer in electronic data files within 3 days of measuring the ride quality using the format specified in Tex -1001-S . The Engineer will use Department software to evaluate longitudinal profiles to determine areas requiring corrective action. Correct 0.1- mi. sections with an average international roughness index (IRI) value greater than 100 in. per mile to an IRI value of 100 in. per mile or less, unless otherwise shown on the plans. Reprofile and correct sections that fail to maintain ride quality before the placement of the surface treatment, as directed. Unless ride deterioration is due to environmental impact, traffic, or other incidents outside the Contractor’s control, perform this work at no additional expense to the Department, as approved.
Article 5 — Measurement
Flexible base will be measured as follows. Flexible Base (Complete in Place) . The ton, square yard, or any cubic yard method. Flexible Base (Roadway Delivery) . The ton or any cubic yard method. Flexible Base (Stockpile Delivery). The ton, cubic yard in vehicle, or cubic yard in stockpile. Measurement by the cubic yard in final position and square yard is a plans quantity measurement. The quantity to be paid is the quantity shown in the proposal, unless modified by Article 9.2., “Plans Quantity Measurement.” Additional measurements or calculations will be made if adjustments of quantities are required. Measurement is further defined for payment as follows.
5.1 Cubic Yard in Vehicle . By the cubic yard in vehicles of uniform capacity at the point of delivery.
169 5.2. Cubic Yard in Stockpile . By the cubic yard in the final stockpile position, by the method of average end areas, or as shown on the plans.
5.3 Cubic Yard in Final Position. By the cubic yard in the completed and accepted final position. The volume of
base course is computed in place by the method of average end areas between the original subgrade or existing base surfaces and the lines, grades, and slopes of the accepted base course, or as shown on the plans.
5.4 Square Yard . By the square yard of surface area in the completed and accepted final position. The surface
area of the base course is based on the width of flexible base, or as shown on the plans.
5.5 Ton. By the ton of dry weight in vehicles as delivered. The dry weight is determined by deducting the weight of the moisture in the material at the time of weighing from the gross weight of the material. The Engineer will
determine the moisture content in the material in accordance with Tex -103-E from samples taken at the time of weighing. When material is measured in trucks, the weight of the material will be determined on certified scales, or the Contractor must provide a set of standard platform truck scales at an approved location. Scales mus t meet the requirements of Item 520, “Weighing and Measuring Equipment.”
Article 6 — Payment
The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for the types of work described below. No additional payment will be made for thickness or width exceeding that shown on the typical section or provided on the plans for cubic yard in the final position or square yard measurement. Sprinkling and rolling, except proof rolling, will not be paid for directly, but will be subsidiary to this Item unless otherwise shown on the plans. When proof rolling is shown on the plans or directed, it will be paid for in accordance with Item 216. Where subgrade is constructed under this Contract, correction of soft spots in the subgrade will be at the Contractor’s expense. Where subgrade is not constructed under this Contract, correction of soft spots in the subgrade will be paid in conformance with pertinent Items or in accordance with A rticle 4.4., “Changes in the Work.”
6.1 Flexible Base (Complete in Place) . Payment will be made for the type and grade specified. For cubic yard
measurement, “In Vehicle,” “In Stockpile,” or “In Final Position” will be specified. For square yard measurement, a depth will be specified. This price is full compensation for furnishing materials, temporary stockpiling, assistance provided in stockpile sampling and operations to level stockpiles for measurement, loading, hauling, delivery of materials, spreading, blading, mixing, shaping, placing, compacting, reworking, finishing, correcting locations where thickness is deficient, curing, furnishing scales and labor for weighing and measuring, equipment, labor, tools, and incidentals.
6.2 Flexible Base (Roadway Delivery) . Payment will be made for the type and grade specified. For cubic yard
measurement, “In Vehicle,” “In Stockpile,” or “In Final Position” will be specified. The unit price bid will not include processing at the roadway. This price is full compensation for furnishing materials, temporary stockpiling, assistance provided in stockpile sampling and operations to level stockpiles for measurement, loading, hauling, delivery of materials, furnishing scales and labor for weighing and measuring, equipment, labor, tools, and incidentals.
6.3 Flexible Base (Stockpile Delivery). Payment will be made for the type and grade specified. For cubic yard measurement, “In Vehicle” or “In Stockpile” will be specified. The unit price bid will not include processing at the roadway. This price is full compensation for furnishing and disposing of materials, preparing the stockpile
area, temporary or permanent stockpiling, assistance provided in stockpile sampling and operations to level 170 stockpiles for measurement, loading, hauling, delivery of materials to the stockpile, furnishing scales and labor for weighing and measuring, equipment, labor, tools, and incidentals.