306 – CEMENT TREATED BASE
300-20 g. Compressive Strength Determination. Using random numbers, select and obtain sampled material at the
plant. Make and cure compression test specimens to represent each sublot. Make and cure compression test specimens, and determine the 7-day compressive strength of the CTB according to Part V. Sulfur cap compression test specimens in accordance with AASHTO T 2 31. When additional test specimens are taken for early determination of the compressive strength, the specimens are for information only. Perform the 7-day compressive strength testing. Maintain records of all sampling and testing. The Engineer will witness all compressive strength tests and initial the Contractor’s documentation. A percent within limits ( PWL ) analysis shall be made on a lot-by-lot basis and shall be based on Contractor quality control test results on all quality control samples representing the lot of the completed CTB. The PWL result shall be determined as specified under Computation of Pay Factor. Compute the pay adjustment as shown in Equation 2. It shall be based on the compressive strength values within each lot and the lower specification limits (LSL). KDOT will use a spreadsheet program to calculate pay adjustments for compressive strength and to compare the Contractor’s QC and KDOT’s verification test results. If the comparison fails, KDOT’s value will be used to calculate the pay adjustment for that lot. The lot comparison is based on KDOT’s verification result falling within the Contractor’s mean, plus or minus 2 times th e Contractor’s sample standard deviation. When the Contractor’s sample standard deviation is less than 260 psi, then 260 psi shall be used for the sample standard deviation during lot comparison with KDOT’s value. When there are 3 or more tests in a lot and when the lot comparison between Contractor and KDOT tests pass, the Contractor’s actual standard deviation will be used to calculate the compressive strength pay factor. When reques ted, KDOT will provide a copy of this program to the Contractor. It is the Contractor’s responsibility to obtain the software required to run this program. Values computed using equations referenced in this specification may vary slightly from the spreadsheet values due to the rounding of numbers. In such cases , the numbers computed by the spreadsheet shall take precedence. A typical lot is defined as a normal day’s placement. At the beginning of the project, estimate the quantity to be placed during a normal day and submit to the Engineer for approval. Once approved, break the quantity into 4 equal parts (each part represents a sublot). Determine a random location for sampling w ithin each sublot. When the total quantity for the day deviates from expectations, adjust the number of sublots based on TABLE 306-1 . TABLE 306-1: SUBLOT BREAKDOWN OF A NORMAL DAY’S PRODUCTION Number of Sublots % of Daily Quantity 4 75-115 3 50-74 2 25-49 1 1-24 Adjust the quantity of the last sublot to accommodate any minor chan ges in production, and adjust the random location for sampling based on the size of the sublot. When there is only 1 test in a lot, the pay factor will be automatically calculated by the KDOT spreadsheet using a sample standard deviation of 260 psi and n of 3. When there are 2 tests in a lot, the pay factor will be calculated by the KDOT spreadsheet using a spreadsheet calculated standard deviation and n of 3. When there are 3 or 4 tests, the lot stands on its own. Regardless of the number of Contractor tests in a lot, the lot comparison between Contractor and KDOT tests will apply. When the quantity exceeds 115% of the normal daily quantity, in crease the number of sublots and restrict the 4 th sublot to a maximum of 100% of the established normal daily quantity. Each sublot added may have a maximum of 25% of the normal daily quantity. Compute the sample standard deviation as shown in Section 5.2.1-Statistics, Part V. Calculate the Compressive Strength Quality Indices ( QL) for each lot as shown in Section 5.2.1-Statistics, Part V. Use the following definitions, and round to the nearest hundredth. Where: X is the average measured compressive streng th of all QC samples representing a lot, rounded to 1.0 psi. LSL is the lower specification limit for compressive strength, defined as 650 psi. S is the sample standard deviation of the compressive strength of all QC samples representing a lot, rounded to 0.1 psi. 306 – CEMENT TREATED BASE 300-21 Determination of the percent within limits ( PWL ) values. Use the computed Q value to determine the compressive strength percent within limits value ( PWL C) by locating the QL values in the left column of the PWL Table in Section 5.2.1-Statistics, Part V. Select the appropriate PWL C by moving across the selected QL to the column representing the number of samples in the lot. When the computed QL is a negative value ( X lies below the LSL), the Engineer will determine if the material in the lot may remain in place. If the material is left in place, and there were no individual plugs found to be less than 600 psi, then 50.00 is assigned as the PWL value. For results exceeding these limits and permitted to remain in place, use the calculated PWL value. When the computed QL is greater than the largest QL value shown in the table, a value of 100.00 is assigned as the PWL value for the designated PWL C. Computation of Cement Treated Base Compressive Strength Pay Adjustment. Compute the pay factor for compressive strength using Equation 2 and round to neares t thousandth (0.001). Multiply the pay factor times the square yards, times $5.00 per square yard to determine the pay adjustment. Equation 2: 0.1351000.15)x (PWL PC Cement Treated Base Compressive Strength Pay Factor (Failing Comparison Test). When the comparison between Contractor and KDOT tests fails, use KDOT test results to calculate the compressive strength pay factor for the lot. Follow the procedures as stated above to determin e the pay factor or disposition of the lot. Use the following values to determine QL: Xof KDOT’s test result for the lot, S of 260 psi, LSL of 650 psi. When selecting the PWL C value from the PWL in TABLE 2, use n of 4.
h.Weather Limitations. Do not place material if the CTB will be exposed to ambient air temperatures below 32ºF during the first 7 days of cure. (See subsections 306.4b., c. and f.). Remove and replace all CTB that is permitted to freeze within the first 24 hours, whether frozen on the surface or full depth. When materials are exposed to freezing ambient air temperatures afte r the first 24 hours but before the 7 day cure period is complete, demonstrate that the 7 day design strength has been achieved. Failure to demonstrate the 7 day design strength has been achieved shall require removal and replacement at Contractor’s expense. As directed by the Engineer and at the Contractor’s expense, repair or replace cured materials exposed to ambient air temperatures below freezing or repeated freeze/t haw cycles that result in loosening or fluffing of the surface. A lift of pavement placed prior to exposure to freezing ambient air temperatures constitutes curing of the CTB. Do not place material on frozen subgrade. Mixing and placing may proceed when th e ambient air temperature is 40ºF and rising, and discontinue when the ambien t air temperatures reaches 45ºF and falling. 306.5 MEASUREMENT AND PAYMENT The Engineer will measure the CTB and quality control testing of CTB by the square yard. Material placed beyond the neat lines indicated in the Contract Documents is not measured for payment unless authorized by the Engineer. Payment for "Cement Treated Base" and "Quality Control Testing (CTB)" at the contract unit prices is full compensation for the specified work. No adjustment of the contract unit price for "Qua lity Control Testing (CTB)" is made for overruns or underruns in the contract quantity. If the PCCP in the contract is specified as QC/QA, (Quality Control Testing (CTB) is included as a bid item), compressive strength pay adjustments will apply under the bid item "Cement Treated Base Compressive Strength Pay Adjustment", and will be shown as an added item to the contract. 307 – GRANULAR BASE
300-22 Section 307
GRANULAR BASE 307.1 DESCRIPTION Construct a granular base on a prepared subgrade as shown in the Contract Documents. B I D I T E M S U N I T S G r a n u l a r B a s e ( * ) S q u a r e Y a r d Water (Granular Base) (Set Price) M Gallon *Thickness 307.2 MATERIALS Provide materials that comply w ith the applicable requirements. Aggregate for Granular Base ................................................................................. DIVISION 1100 Water for Granular Base ........................................................................................ DIVISION 2400 307.3 CONSTRUCTION REQUIREMENTS Recompact soft and yielding subgrad e material. Do not place granular base on frozen subgrade. If the project has more than 20,000 square yards of manipulation, use automatic grade controlled equipment to trim the subgrade. In irregular areas, trim the subgrade by wetting, blading and rolling. Use a stationary mechanical mixing plant to uniformly mix the water and aggregate. A motor grader with water truck, or rotary cross-shaft mixer with water delivery system may be used to mix aggregate and water when the original contract quantity is less than 15,000 square yards. Mix the granular aggregat e with sufficient water to allow compac tion of the mixture to the specified density at ± 3 % of the optimum moisture content. Immediately after mixing the aggregate and water, ha ul the mixture to the prepared subgrade, place the mixture full-lane width using an aggregate spreader, and co mpact the mixture. The Engineer will not allow placing of the base material on the prepared subgrade when cond itions are such that the hauling and placing will damage the prepared subgrade. The maximum compacted thickness of any layer of granular base or shoulder is 6 inches. When the thickness is greater than 6 inches, spread and compact the aggregate in multiple lifts of equal thickness with a maximum lift thickness of 6 inches. Spread and compact the granular base as specified in the Contract Documents. Compact the granular base to a minimum of 95% of the standard density. Compact granular base placed more than 2 feet outside the edge of pavement to a minimum of 90% of the standard density. Trim the compacted granular base to the lines and grades in the Contr act Documents. Compact the surface of the granular base with a smooth-wheel or a pneumatic- tire roller. While performing final rolling, lightly scarify and blade the surface to elim inate equipment imprints. Maintain density until paved. When paving is dela yed and the granular base dries out, re-establish the specified dry density just prior to paving. 307.4 MEASUREMENT AND PAYMENT The Engineer will measure granular base by the square yard. The Engineer will measure water used for granular base by the M Gallon using calibrated tanks or water meters. The Engineer will measure water used for granul ar base preparation, mixing and compacting the granular base. The Engineer will not measure water used for dust c ontrol, water wasted through the Contractor’s negligence, or water in excess of the quantity required for mixing and compacting the granular base. Payment for "Granular Base" at the contract unit pr ice and "Water (Granular Base) (Set Price)" at the contract set unit price is full co mpensation for the specified work. 308 – GEOSYNTHETIC REINFORCED BASE
300-23 Section 308
GEOSYNTHETIC REINFORCED BASE 308.1 DESCRIPTION Place geosynthetic reinforcement for the base at the locations designated in the Contract Documents. B I D I T E M U N I T S Geosynthetic Reinforcement (for Base) Square Yard 308.2 MATERIALS Provide geosynthetic for base course reinforcement that complies with DIVISION 1700 . 308.3 CONSTRUCTION REQUIREMENTS Store and handle the geosynthetic according to the manufacturer's recommendations. Do not expose the geosynthetic to direct sunlight, ultraviolet rays, and temp eratures greater than 140°F, mud, dirt, dust, and debris. Place the geosynthetic on the prep ared surface to the limits shown in the Contract Documents. Overlap parallel strips or roll ends a minimum of 12 to 36 inches as designated on the Contract Documents. Limit placement of geosynthetic to that which can be covered with base material within 72 hours. When placing the base lift over the geosynthetic, do not allow construction traffic di rectly on the geosynthetic. 308.4 MEASUREMENT AND PAYMENT The Engineer will measure the geosyn thetic reinforcement by the square yard to the neat lines shown in the Contract Documents. Payment for "Geosynthetic Reinforcement (for Base)" at the contract unit price is full compensation for the specified work. 401 - GENERAL CONCRETE 400-1 SECTION 401 GENERAL CONCRETE 401.1 DESCRIPTION Provide the grades of concrete sp ecified in the Contract Documents. See SECTION 402 for specific requirements for Structural Concrete. See SECTION 403 for specific requirements for On Grade Concrete. See SECTION 404 for specific requirements for Prestressed Concrete. 401.2 MATERIALS Provide materials that comply w ith the applicable requirements. Aggregate ............................................................................................................... ….. DIVISION 1100 Admixtures and Pl asticizers .................................................................................. ….. DIVISION 1400 Grade 2 Calcium Chloride ...................................................................................... ….. DIVISION 1700 Cement, Fly Ash, Silica Fume, Slag Cement and Blended Supplemental Cementitious ........................................................................................................... …. DIVISION 2000 Water ………………………………………………………………. ..................... ….. DIVISION 2400 401.3 CONCRETE MIX DESIGN
a.General. Design the concrete mixes specifi ed in the Contract Documents. Do not place any concrete on the project until the Engi neer approves the concre te mix designs. Once the Engineer approves the concrete mix design, do not make changes without the Engineer’s approval. Take full responsibility for the actual proportions of the concrete mix, even if the Engineer assists in the design of the concrete mix. Provide aggregate gradations that comply with DIVISION 1100 and Contract Documents. If desired, contact the DME for available information to help determine approximate proportions to produce concrete having the required characteristics on the project. Submit all concrete mix designs to the Engineer for review and approval. Submit completed volumetric mix designs on KDOT Form No. 694 and all required attachme nts at least 60 days prior to placement of concrete on the project. The Engineer will provide an initial review of th e design within 5 business days following submittal. Include the following with the mix design data:
1.Test data.
a.Test data from KT-73 tested at 28 days, KT-79 tested at 28 days or AASHTO T-277 tested at 56 days for all bridge overlays, Moderate Permeability Concrete, and any project with over 250 cubic yards of concrete (this includes structural co ncrete, on grade concrete etc.). Provide the test data for each mix, tested at the highest paste content (cementitious and water) that meets subsection 401.3h . Submit accelerated cure procedures fo r the Engineer’s approval. The field verification test procedure must be the same test procedure as the mix design approval test.
b.Test data from ASTM C 1567 for field blended cements meeting subsection 401.3d.(6) for all concrete utilizing all actual materials proposed for use on the project at designated percentages.
2.Single point grading for the combined aggregates along with a plus/minus tolerance for each sieve. Use plus/minus tolerances to perform quality control checks and by the Engineer to perform aggregate grading verification testing. The tests may be performed on the co mbined materials or on individual aggregates, and then theoretically combined to determine compliance.
3.Laboratory 28 day compressive strength test results on a minimum of 1 set of 3 cylinders produced from the mix design with the highest water to cementitious ratio for the project, utilizing all actual materials proposed for use on the project at designated percentages.
4.Historical mix production data for the plant producing concrete for the project to substantiate the standard deviation selected for use in subsection 401.3b .
5.Necessary materials to enable the Engineer to test the mix properties and Surface Resistivity, if applicable. 401 - GENERAL CONCRETE 400-2 After initial review, the Engineer will perform any testing necessary to veri fy the design. This may include a 3 cubic yard test batch at the producing plant. Mix designs will remain approved when verification testing for strength and permeability conducted within the last 12 months indicate continued compliance with the specifications and percentages of constituents including aggregate and cementitious materials and product, type and supplier of admixtures remain the same. Test results on the same mix from other sources are acceptable. Provid e ASTM C 1567 results on an annual basis if the mix includes supplemental cementitious materials (SCM). Improvements in concrete strength, workability, durability and permeability are possible if the combined aggregate grading is optimized. Procedures found in ACI 302.1 or other mix design techniques, approved by the Engineer, are acceptable in optimizing the mix design. A water-reducing admixture for improving workability may be required. Adjust the designated slump accordingly. With the exception of concrete for pavement as shown in SECTION 403 , use the middle of the specified air content range of 6½ ± 1.5% for the design of air entrained concrete. Maximum air content is 10%. Take immediate steps to reduce the air content whenever the air content exceeds 8%. Determine air content by KT-19 (Volumetric Method). A regularly calibrated KT-18 (Pressure Method) meter may be used for production with random verification by the Volumetric Method. See KT-19 for special requirements when using the Volumetric Method with high cementitious concretes or mixtures with midrange water reducers or plasticizers. Delay the commencement of tests from 4 to 4½ minutes after the sample has been taken from a continuous mixer. If a batch type mixer is used, take the tests at the point of pl acement and begin testing immediately.
b.Concrete Mix Design Based On Previous Data. Provide concrete mix designs based on previous 28- day compressive strength test data from similar concrete mixtures. Similar mixtures are within 1000 psi of the specified 28-day compressive strength, and are produced w ith the same type and sources of cementitious materials, admixtures and aggregates. Consider sand sources the same, provided they are not more than 25 miles apart on the same river and no tributaries enter the river between the 2 points. Consider crushed locations similar if they are mined in one continuous operation, and there is no significant change in geology. Mixes that have changes of more than 10% in proportions of cementitious materials, aggregates or water content are not considered similar. Air entrained mixes are not considered similar to non-air entrained mixes. Mixes tested with admixtures are not the same as mixes tested with out those admixtures. Test data should represent at least 30 separate batches of the mix. One set of data is the average of at least 2 cylinders from the batch. The data shall represent a minimum of 45 days of production within the past 12 months. Do not include data over 1 year old. When fewer than 30 data sets are available, the standard deviation of the data must be corrected to compensate for the fewer data points. Provide a concrete mix design that will permit no more than 5% of the 28-day compressive strength tests to fall below the specified 28-d ay compressive strength ( f’c) based on equation A, and no more than 1% of the 28-day compressive strength tests to fall below th e specified 28-day compressive strength ( f’c) by more than 500 psi based on equation B. Equation A: f’cr = f’c + 1.62 *k*s Equation B: f’cr = (f’c-500) + 2.24 *k*s Where: f’cr = average 28-day compressive streng th required to meet the above criteria. f’c = specified 28-day compressive strength s = standard deviation of test data k = constant based on number of data points n = number of data points k = 1.3 – n / 100, where 15 < n < 30 k = 1, where n > 30 Provide a concrete mix design that has an average comp ressive strength that is equal to the larger of Equation A or Equation B. Submit all supporting test data with the mix design. 401 - GENERAL CONCRETE 400-3 All other concrete mix designs. For concrete mixes that have fewer than 15 data points, or if no statistical data is available, use Equations A and B to calculate f’cr using the following values. s = 20% of the specified 28-d ay compressive strength ( f’c) k = 1
c.Portland Cement and Bl ended Hydraulic Cement. Unless specified otherwise in the Contract Documents, select the type of portland cem ent or blended hydraulic cement according to TABLE 401-1 . Design concrete with a maximum water to cementitious ratio of 0.50 and minimum cementitious content of 480 lbs per cubic yard except for concrete for pavement and shoulders.
d.Blended Cement Concrete. When approved by the Engineer, the concrete mix design may include SCMs such as fly ash, slag cement, silica fume or blended SCM from an a pproved source as a partial replacement for portland cement or blended hydraulic cement. Obtain the Engineer’s approval before substituting SCMs for Type III cement. Changes in SCM or cemen t will require a new mix design approval.
1.Cements meeting SECTION 2001 are not field blended cements.
2.Cements with SCMs added at the concrete mixing plant are field blended cements.
3.Supplementary materials can be combined with cement to create fiel d blended cements. Do not exceed allowable substitution rates noted in TABLE 401-2 . Substitute 1 pound of SCM for 1 pound of cement.
4.SCMs in prequalified cements are to be in cluded in the total combined substitution rate. TABLE 401-2: ALLOWABLE SUBSTITUTION RATE FOR SUPPLEMENTARY CEMENTITIOUS MATERIAL. Material Substitution Rate* Slag Cement 40% Maximum Fly Ash 25% Maximum Blended SCM 25% Maximum Silica Fume 5% Max Total Combined 50% * Total Substitution Rate includes material in preblended cements and blended SCMs.
5.Design field blended cement concrete meeting the applicable requirements for Volume of Permeable Voids, Surface Resistivity, or Rapid Chloride Permeability using the parameters described in subsection 401.3a .
6.For field blended cementitious material provide mortar expansion test results from ASTM C 1567 using the project’s mix design concrete materials at their designa ted percentages. Provide a mix with a maximum expansion of 0.10 % at 16 days after casting. ASTM C 1567 is not necessary for concrete modified with only silica fume. TABLE 401-1: PORTLAND CEMENT & BLENDED HYDRAULIC CEMENT Concrete for: Type of Cement Allowed On Grade Concrete Type IP(x) Portland-Pozzolan Cement Type IS(x) Portland- Slag Cement Type IT(Ax)(By) Ternary Blended Cement Type II Portland Cement All Concrete other than On Grade Concrete. Type I Portland Cement Type IP(x) Portland-Pozzolan Cement Type IS(x) Portland- Slag Cement Type IT(Ax)(By) Ternary Blended Cement Type II Portland Cement High Early Strength Concrete Type III Portland Cement Type I, IP(x), IS(x), IT(Ax)(By), or II Cement may be used if strength and time requirements are met. 401 - GENERAL CONCRETE 400-4 When used, add silica fume with other cementitious materials during batching procedures. If the silica fume cannot be added to the cementitious materials, add th e loose silica fume to the bo ttom of the stationary drum that is wet, but has no standing water, before adding the dry materials. The Engineer may approve shreddable bags on a performance basis, only when a central batch mixing process is used. If so, add the bags to half of the mixing water and mix before adding cementitious materials, aggregate and remainder of water. Mix silica fume modified concrete for a minimum of 100 mixing revolutions.
7.Submit complete mix design data including proportions and sources of all mix ingredients, and the results of strength tests representing the mixes proposed for use. The strength data may come from previous KDOT project records or from a laboratory regularly inspected by Cement and Concrete Reference Laboratory (CCRL), and shall equal or exceed the strength requirements for the Grade sp ecified in the Contract Documents as determined by subsection 401.3b . Perform compressive strengt h tests according to KT-76.
e.Strength. Design concrete to meet TABLE 401-3 . TABLE 401-3: CONCRETE STRENGTH REQUIREMENTS Specified 28 Day Compressive Strengths, minimum, psi f’c Grade of Concrete: Non Air Entrained/Air Entrained Concrete Grade 7.0 7,000 Grade 6.0 6,000 Grade 5.0 5,000 Grade 4.5 4,500 Grade 4.0 4,000 Grade 3.5 3,500 Grade 3.0 3,000 Grade 2.5 2,500
f.High Early Strength Concrete. Design the high early strength concrete mix to comply with strength and time requirements specified in the Contract Documents. Unless otherwise specified, design high early strength concrete for pavement at a minimum of 1 of the Contractor’s standard deviations above 2400 psi (cylinders) at 24 hours. Submit complete mix design data including proportions and sources of all mix ingredients, and the results of time and strength tests representing the mixes proposed for us e. The strength and time data may come from previous KDOT project records or from an independe nt laboratory, and shall equal or ex ceed the strength and time requirements listed in the Contract Documents.
g.Slump. Designate a slump for each concrete mix design th at is required for satisfactory placement of the concrete application not to exceed 5 inches except wh ere controlled by maximum allowable slumps stated in SECTIONS 402, 403 and 404 . Reject concrete with a slump that limits the workability or placement of the concrete.
h.Permeability. Except for Structural Concrete as shown in SECTION 402 , supply a concrete with either a maximum 28 day Volume of Permeable Voids of 12.0% as per KT-73, a minimum 28 day surface resistivity of 9.0 kΩ-cm as per KT-79, or a maximum 56 day Rapid Chloride Permeability of 3,000 Coulombs as per AASHTO T- 277. The field verification test procedure must be the same test procedure as the mix design approval test.
i.Admixtures for Acceleration, Ai r-Entraining, Plastici zing, Set Retardation and Water Reduction. Verify that the admixtures used are compatible and will wo rk as intended without detrimental effects. Use the dosages recommended by the admixture manufacturers. Incorporate and mix the admixtures into the concrete mixtures according to the manufacturer’s recommendations. Determin e the quantity of each admixture for the concrete mix design. The Engineer will allow minor adjustments to the dose rate of admixtures to compensate for environmental changes during placement without a new concrete mix design or trial batch.
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 166–173 of 978.