305 – AGGREGATE BASE AN D AGGREGATE SHOULDERS
300-14 c. Placing, Compacting and Finishing. Immediately after mixing the aggregate and water, use an
aggregate spreader to place the mixture full-lane or full-shoulder width. Do not place the mixed material on the prepared subgrade when conditions are such that the haul ing and placing will damage the prepared subgrade. Do not dump or mix the aggregate on any paved surface. The maximum compacted thickness of any layer of aggreg ate base or shoulder is 6 inches. If the thickness is greater than 6 inches, spread and compact the aggregat e base in multiple lifts of equal thickness with a maximum lift thickness of 6 inches. The maximum compacted thic kness of any layer may be increased to 8 inches when vibrating compaction equipment or other compaction equipment is approved by the Engineer. On aggregate course projects without shoulders, construct all lifts, regardless of th ickness, with an edge slope of 1:1 or flatter. If the aggregate base or shoulder is constructed in more than 1 la yer, allow sufficient time for the initial layer to cure to prevent any rutting or surface di stortion from equipment being used to place the succeeding layers. Spread and compact the aggregate ba se or shoulders as specified in th e Contract Documents. Compact the aggregate base to a minimum uniform density of 95% of the standard density. Comp act the aggregate shoulders until no further consolidation is gained by additional blading and rolling. The Engineer will visually verify compaction of the a ggregate shoulders. After compacting the aggregate base, trim the surface to the specified lines and grades. On projects having more than 20,000 square yards of aggregate base, use automatic grade controlled equipment to trim the compacted aggregate base. In irregular areas, trim the aggregate ba se by wetting, blading and rolling. Compact the trimmed surface of the aggregate base with a sm ooth-wheel or a pneumatic-tire roller. When necessary, lightly scarify and blade the surface to eliminate equipment imprints while performing final rolling.
d.Curing and Maintena nce of Aggregate Base. Cure the compacted layer to develop sufficient stability to resist wheel truck rutting before vehicular hauling or h eavy equipment is permitted on the base. When Contract Documents call for a PGAB or cutback asphalt prime coat on the aggregate base, cure the compacted layer to maximum moisture content of 60% of optimum moisture content for AB-1, AB-2, & AB-4 and 70% for AB-3, prior to the construction of the Asphalt Prime Coat. The Engineer will perform testing to determine when the cure of the aggregate base is complete. The Engineer may require th at the surface of the aggregate base be kept moist during the curing period to prevent loss of surface material. Do not apply surfacing until the aggregate base is cured. Maintain the base until the surfacing is applied.
e.Shoulders, Entrances and Side Roads. When shoulder construction is not included in the Contract Documents, re-construct, compact and sh ape the existing shoulder from the top of the completed aggregate base to the shoulder line. Shape the shoulders to provide a uniform shoulder line. Raise the grade of entrances and side roads to meet the edge of the completed aggregate base. Construct, compact and shape the entrances and side roads full widt h with shoulders and shoulder radii adjacent to the shoulders of the roadway. Obtain additional embankment material for shoulders, entrances and side roads from adjacent slopes and ditches. Dispose of excess material from shoulders, entrances and side roads on adjacent backslopes. 305.4 MEASUREMENT AND PAYMENT The Engineer will measure aggregate base an d aggregate shoulder by the square yard. The Engineer will measure the water used in the mixture and used on the finished surface during the curing period by the M Gallon using calibrated tanks or distributors . The Engineer will not measure water in the mixture in excess of 5% above the optimum moisture. The Engineer will not measure water used for subgrade preparation or construction of earthen shoulders, entr ances and side roads. The Engineer will not measure water used for dust control or water wasted through the Contractor’s negligence. The Engineer will measure Grade 2 calcium chloride (c oncentrated calcium chloride or equivalent) used in the mixture by the ton. If Grade 1 calcium chloride (regular) is used, 1.2 tons of Grade 1 is the equivalent of 1 ton of Grade 2. The Engineer will not measure the wedges at the pavement edge. Payment for "Aggregate Base", "Aggregate Shoulders" and "Calcium Chloride" at the contract unit prices and "Water (Aggregate Base) (Set Price)" and "Water (Aggregate Shoulders) (Set Price)" at the contract set unit prices is full compensation for the specified work. 306 – CEMENT TREATED BASE
300-15 Section 306
CEMENT TREATED BASE Exception: If the PCCP in the contract is not specified as QC/QA, (Bid item Quality Control Testing (CTB) is not included as a bid item) subsections 306.2 (entire subsection), 306.4d. and 306.4g. of this SECTION are not applicable to the contract. 306.1 DESCRIPTION Design a cement treated base (CTB) mixture meeting the requirements of the Contract Documents. Construct 1 or more courses of the CTB on a prepared roadway as shown in the Contract Documents. B I D I T E M S U N I T S Cement Treated Base Square Yard Quality Control Testing (C TB) Square Yard 306.2 CONTRACTOR QUALITY CONTROL REQUIREMENTS
a.General . Provide qualified personnel an d sufficient equipment complying with the requirements listed in Part V to conduct quality control testing that complie s with Appendix B, Sampling and Testing Frequency Chart for Concrete Construction Items for Qua lity Control/Quality Assurance Projects. Allow the Engineer access to the Contractor’s laborato ry to observe testing procedures, calculations, test documentation and plotting of test results. Calibrate and correlate the testing equipment with pr escribed procedures, and co nduct tests in compliance with specified testing procedures as listed in Part V. Maintain a Quality Manual in the field laboratory show ing the calibrations performed on all test equipment and when the next calibration is due for that equipment. As a minimum, follow the calibration/verification interval established in Table 1: Concrete Materials Test Equipment in Section 5.2.7.8-Cement Treated Base: Contractor’s Quality Control Plan (CTB), Part V. See also, Part V Section 5.2.7.8.1-Exam ple of a Laboratory Quality Manual for CTB. Provide personnel and equipment to conduct quality control testing that complies with the Contract Documents. Provide certified technici ans to perform process control testing. Use equipment that complies with, and is calibrated according to the specified test methods.
b.Quality Control Plan (QCP). At the pre-construction conference, submit to the Engineer for approval by the DME, a QCP as outlined in Section 5.2.7-Contractor ’s Quality Control Plan, Part V. Follow 5.2.7.8-Cement Treated Base: Contractor’s Quality Control Plan in Part V as a general guideline. Keep a printed copy of the approved QCP in the Contractor’s laboratory and make available to the Engineer when requested. The Contractor’s laboratory and equipment will be insp ected and approved as outlined in Part V, Section 5.2.7-Contractor’s Quality Control Plan. Include a listing of the names and phone numbers of individuals and alternates responsible for quality control administration and inspection. On the Contractor’s organizational chart, show the specified lines of authority relating both to mix design and quality control oper ations during production. Post the organizational chart in the Contractor’s test facility. Provide a quality control organization or private testing firm having pe rsonnel certified according to the Policy and Procedures Manual for The Certified Inspection a nd Testing (CIT) Training Program. The testing for this type of construction will require personnel certified in ACI Concrete Field Testing Technician (CF), Aggregate Field Tester (AGF), Soils Field Tester (SOF) and Nuclear Moisture Density Gauge Tester (NUC) classifications. Only persons certified in the appropriate classifications covering the specific tests required shall perform such testing. Provide a minimum of 1 employee on the project certified in the QC/QA Concrete/Cement Treated Base Specs (QCS) classification. Only persons certified in the approp riate classifications covering the specific tests required shall perform such testing. At the beginning of the project, provide the Engineer with the list of certified technicians and 306 – CEMENT TREATED BASE
300-16 alternates, phone numbers and tests/inspection they will be performing. As personnel changes and certifications
may expire, continue to provide the Engineer with an accurate list. Provide an organizational chart showing the specified lines of authority relating to both mix design and quality control operations during production. Identify the company official acting as liaison with KDOT, and the Certified Technician who will direct inspection and testing. Post the chart in the test facility. Submit the mix design for the CTB. If an existing mix design is used, provide the mix design number. Include all the elements of the mix design specified in the Contract Documents. Submit the proposed methods and procedures to control the elements identified as necessary for the quality of the CTB. These elements include, but are not limited to: producing the aggregate, managing the aggregate stockpiles, proportioning the individual materials for the mixture, mixing and transporting the mixture, placing and consolidating the mixture, and finishing and curing the mixture.
c.Required Duties of Certified Technicians. Be available on the project site whenever cement treated base is being produced and being placed on the project site. Perform and utilize quality control tests and other quality control practices to assure that delivered materi als and proportioning meet the requirements of the mix designs, including temperature, slum p, air content and strength. Periodically inspect all equipment utilized in transporting, proportioning, mixing, placing, consolidating, finishing and curing to assure it is op erating properly and that placement, cons olidation, finishing and curing comply with the mix design and other contract requirements.
d.Contractor’s Testing Facilities. Describe the testing facility an d its accreditation in the QCP. Locate the testing facility either at the plant site or at the project. Obtain approval of the testing facilities and location from the DME before the commencement of mixture production. Provide suitable space for the required testing equipment. Also, equi p the testing facility with these items for the exclusive use of the testing facility’s quality control personnel and the Engineer: A telephone with a private line; A copying machine; and Broadband internet connection (for 1 computer). If the Engineer determines that broadband internet service is not available, provide a fax machine, at no additional cost.
e.Documentation. Include in the QCP procedures, charts and fo rms to be used to provide the required documentation. Record and document all test results and calculations. Record all original documentation in a bound field book or other KDOT approved bound record and turn over to KDOT at the end of the project. At all times, have complete records of all inspections and tests readily available on site for the Engineer. All records documenting the Contractor’s quality control inspections and tests become the property of KDOT upon completion of the work. Indicate the nature and number of observations made, the number and type of deficiencies found, the quantities approved and rejected, and the corrective action taken in the records. Examples of quality control forms and charts are available in Part V, or Contractors may design their own. Documentation procedures are subject to approval by the Engineer before the start of the work an d to compliance checks during the progress of the work. Maintain control charts on an ongoing basis. Plot data according to SECTION 106 . Record all test results and calculations on electronic da ta sheets. Record specifi c test results on a Daily Quality Summary Sheet to facilitate the computation of moving test averages. Base the moving averages on 4 consecutive test results. Include a description of quality control actions taken (adjustment of aggregate or additive proportions in the mix, moisture adjustments, etc.) in the Daily Quality Summary Sheet. Provide forms on a computer-acceptable medium, where required. Document batch tickets and gradation data according to KDOT requirements. Complete testing and charting with in 1 working day after sampling. Keep all quality control charts current. Email or fa x the data to the Field Engineer and DME, weekly. Show both individual test results and moving average values. As a minimum, plot the single test values and the 4- test moving average values for gradation of combined aggregates, in-place CTB moisture and dry density, and compressive strength (requires a separate graph for PWL, but no moving average plot). Complete the charting within 1 working day after the sa mpling or testing, respective to each type of test. Make all test results and control charts available to the Engineer at the project site. The Engineer will periodically make compliance checks on the documentation during the progress of the work. 306 – CEMENT TREATED BASE
300-17 Submit (email or fax) copies of all failing test results (based on a moving average of 4 tests, if appropriate)
and a summary sheet to the Field Engineer on a daily basis. File all reports, records, charts and diaries developed during the progress of construction activities. Upon completion of the contract, all document ation becomes the property of KDOT.
f.Testing Requirements. In the QCP, identify test methods, procedures and equipment proposed for use. Use standard KDOT test methods and properly calibrated m easuring and testing equipment as outlined in Part V. Detail any alternative sampling method, procedure or inspec tion equipment proposed to be used. Such alternatives are subject to review and approval by the DME. Take all samples for tests and perform in-place test s at random locations se lected according to the Contractor’s QC Plan and at the rate s specified in the Sampling and Testi ng Frequency Chart for Cement Treated Base for Quality Control/Quality Assurance Projects in Append ix B, Part V. Retain the latest 10 gradation samples for use by the Engineer. Retain the second half of the latest 10 gradation samples for use by the Engineer.
g.Mix Design. Design a mixture of aggregate and portland cement or fly ash, or both. If fly ash is used in the mixture, address the set time and strength gain as a function of the ambient temperature. Design the mixture according to the following requirements:
1.The compressive strength shall be between 650 and 1600 psi. Any test correlating to the maximum value or higher requires scoring or sa wing joints in the base that fall within the failing test se ction (from previous to next passing test sections). Determine compressive strength at 7 days, according to Part V.
2.Submit a single point gradation for the combined ag gregates along with a plus/minus tolerance for each sieve to the Engineer. The plus/minus tolerances shall be used by the Contractor to perform quality control checks and by the Engineer to perform aggreg ate gradation verification testing. Perform tests on the combined materials.
3.Submit the mix batch weights in an acceptable manner to the DME. Address the initial set times (specified in AASHTO T 154) and placement times (with regards to the set times) in the proposed mix design.
4.Submit laboratory compressive strength test results on a minimum of 1 set of 3 plugs, produced from the proposed mix design and utilizing the actual materials proposed for use on the contract.
5.Submit the test results 2 weeks prior to the anticipated date for using the design on the contract. The Engineer will review the design within 5 working days of receipt. The Engine er may perform any testing necessary to verify the adequacy of the Contractor’s design. If the Engineer calls for verification tests, supply the Engineer with the necessary materials to enable the Engineer to test the mix properties within 5 working days of notification.
6.Submit any proposed changes to the approved mi x design to the DME for approval before implementing the proposed changes.
h.Corrective Action. In the QCP, identify procedures for notifying the Engineer when corrective measures must be implemented, and for halting production. Notify the Engineer when the moving average test result trend line for any property approaches the specification limits. Cease operations when 2 consecutive moving average points fall outside the specification limits, or 2 consecutive single compressi ve strength tests exceed the specificati on limits. Ceasing operations is the Contractor’s responsibility. Quality control tests for this determination include aggregate gradation, compliance with the mix design band and in-place density of CTB. Failure to cease operations for the c onditions cited above will subject all su bsequent material to rejection, or acceptance at a reduced price, as determined by the Engineer. The Engineer may examine materials represented by individual test results, which lie beyond the Contractor’s normal quality control testing variation. The investigation may be based on either Contractor or KDOT test results. The information from add itional testing (including testing of in-p lace pavement) may be used to define unacceptable work according to SECTION 105 . The Engineer will apply appropriate price reductions or initiate corrective action. If a dispute exists between the Engineer and Contractor about the validity of any test results other than compressive strengths or thickness determination, the K DOT District Materials Laboratory or MRC will perform referee testing. If one of the disputed KDOT test results was generated at the MRC, then an independent laboratory agreeable to both parties will be se lected. The AASHTO Accr editation Program shall have approved the selected laboratory for the appropriate test procedure. If refer ee testing indicates that KDOT test results are correct, the Contractor is responsible for the cost of additional testing, including referee testing performed at the MRC. If the
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 160–163 of 978.