421Hydraulic Cement Concrete

2.1 Cement . Furnish cement in accordance with DMS -4600 , “Hydraulic Cement.”

2.2 Supplementary Cementitious Materials (SCMs).

 Coal Ash . Furnish sources of fly ash, modified fly ash (MFA), harvested coal ash (HCA), and ground bottom ash (GBA) in accordance with DMS -4610 , “Coal Ash .”  Slag Cement . Furnish slag cement in accordance with DMS -4620 , “Slag Cement.”  Silica Fume. Furnish silica fume in accordance with DMS -4630 , “Silica Fume.”  Natural Pozz olans . Furnish natural pozzolans in accordance with DMS -4635 , “Natural Pozzolans.”

2.3 Cementitious Material . Cementitious materials are the cement and SCMs used in concrete.

2.4 Chemical Admixtures. Furnish admixtures in accordance with DMS -4640 , “Chemical Admixtures for

Concrete.”

2.5 Water . Furnish mixing and curing water that is free of oils, acids, organic matter, or other deleterious

substances. Water from municipal supplies approved by the Texas Department of Health will not require testing. Provide test reports showing compliance with Table 1 before use when using water from other sources. Water that is a blend of concrete wash water and other acceptable water sources, certified by the concrete producer as complying with the requirements shown in Table 1 and Table 2, may be used as mix water. Test the blended water weekly for 4 weeks for compliance with Table 1 and Table 2 or provide previous test results. Then test every month for compliance. Provide water test results upon request. Do not use mix water that has an adverse effect on the air -entraining agent, on any other chemical admixture, or on strength or time of set of the concrete. Use mixing and curing water free of iron and other impurities that may cause staining or discoloration when using white hydraulic cement. 527 Table 1 Chemical Limits for Mix Water Contaminant Test Method Max Concentration (ppm or mg\L) Chloride (Cl) ASTM C1141 Prestressed concrete 500 Bridge decks & superstructure 500 All other concrete 1,000 Sulfate (SO4) ASTM C1141 2,000 Alkalis (Na2O + 0.658K2O) ASTM C1141 600 Total solids ASTM C1603 50,000 1. ASTM C114 includes reference and alternative test methods to measure the concentration of chlorides, sulfates, and alkalis in solutions prepared from dissolving cementitious materials. Use the applicable Test Methods in C114 to measure these constituents. The laboratory performing these tests is not required to conform to the method qualification requirements of Test Methods C114. Alternative instrumental and wet chemistry methods not listed in Test Methods C114 that measure the concentration of these chemical species in solution are permitted. When alternative methods are used, the test method used will be included in the report. Table 2 Acceptance Criteria for Questionable Water Supplies Property Test Method Limits Compressive strength, Min % control at 7 days ASTM C31, ASTM C391,2 90 Time of set, deviation from control, h:min. ASTM C403 From 1:00 early to 1:30 later 1. Base comparisons on fixed proportions and the same volume of test water compared to the control mix using 100% potable water or distilled water. 2. Base comparisons on sets consisting of at least two standard specimens made from a composite sample.

2.6 Aggregate .

2.6.1 Coarse Aggregate. Provid e coarse aggregate consisting of durable particles of gravel, crushed blast

furnace slag, recycled crushed hydraulic cement concrete, crushed stone, or combinations that are free of frozen material and injurious amounts of salt, alkali, vegetable matter, or other objectionable material, either free or as an adherent coating. Provide coarse aggregate of uniform quality throughout. Provide coarse aggregate with the requirements shown in Table 3 unless otherwise shown on the plans. Table 3 Coarse Aggregate Req uirements Description Test Method Limit Weight of clay lumps, % Max Tex-413-A 0.25 Weight of shale, % Max 1.0 Weight of laminate and friable particle, % Max 5.0 L.A. abrasion wear, % Max Tex-410-A 40 5-cycle magnesium sulfate soundness,1,2, non -air-entrained concrete, % Max Tex-411-A 25 5-cycle magnesium sulfate soundness,1,3, air-entrained concrete, % Max 18 Loss by decantation, % Max Tex-406-A 1.5 1. Recycled crushed hydraulic cement concrete is not subject to 5 -cycle magnesium sulfate soundness requirements. 2. Allowed when air -entrained concrete is used at the Contractor’s option. 3. Only when air -entrained concrete is required by the plans. Increase the loss by decantation limit to 3.0% for all classes of concrete and 5.0% for Class A, B, and P if the material finer than the No. 200 sieve is determined to be at least 85% calcium carbonate in accordance with Tex-406-A , Part III, in the case of coarse aggregates made primarily from crushing stone, unless otherwise shown on the plans. Provide test results upon request. Provide coarse aggregate or combination of aggregates conforming to the gradation requirements shown in Table 4 when tested in accordance with Tex -401-A unless otherwise specified. 528 Table 4 Coarse Aggregate Gradation Chart Aggregate Grade No.1 Maximum Nominal Size Percent Passing on Each Sieve 2-1/2” 2” 1-1/2” 1” 3/4” 1/2” 3/8” #4 #8 1 2” 100 80–100 50–85 – 20–40 – – 0–10 – 2 1-1/2” – 100 95–100 – 35–70 – 10–30 0–10 – 3 1-1/2” – 100 95–100 – 60–90 25–60 – 0–10 – 4 (57) 1” – – 100 95–100 – 25–60 – 0–10 0–5 5 (67) 3/4” – – – 100 90–100 – 20–55 0–10 0–5 6 (7) 1/2” – – – – 100 90–100 40–70 0–15 0–5 7 3/8” – – – – – 100 70–95 0–25 – 8 3/8” – – – – – 100 95– 100 20–65 0–10 1. Corresponding ASTM C33 gradation shown in parentheses.

2.6.2 Fine Aggregate . Provide fine aggregate consisting of clean, hard, durable particles of natural, manufactured

sand; recycled crushed hydraulic cement concrete; slag; lightweight aggregate; or a combination thereof. Provide fine aggregate free of frozen material and injurious amounts of salt, alkali, vegetable matter, or other objectionable material. Provide fine aggregates in accordance with Table 5 unless otherwise shown on the plans. Table 5 Fine Aggregate Requirements Description Test Method Limit Weight of clay lumps, % Max Tex-413-A 0.50 Organic impurities1 Tex-408-A Color not darker than standard Sand equivalent, Min Tex-203-F 80 Fineness modulus Tex-402-A 2.3–3.1 1. Only when air -entrained concrete is specified. Provide fine aggregate or combinations of aggregates conforming to the gradation requirements shown in Table 6 when tested in accordance with Tex -401-A unless otherwise specified. Table 6 Fine Aggregate Gradation Chart (Grade 1) Sieve Size % Passing 3/8” 100 #4 95–100 #8 80–100 #16 50–85 #30 25–65 #50 10–351 #100 0–10 #200 0–32 1. 6–35 when sand equivalent value is greater than 85. 2. 0–6 for manufactured sand.

2.6.3 Intermediate Aggregate . Provide intermediate aggregate consisting of clean, hard, durable particles of

natural, manufactured sand; slag; recycled crushed hydraulic cement concrete; lightweight aggregate; or a combination thereof when optimized aggregate gradation (OAG) concrete is specified or when used at the Contractor’s option. Provide intermediate aggregate free of frozen material and injurious amounts of salt, alkali, vegetable matter, or other objectionable material. Provide intermediate aggregate in accordance with Table 7. 529 Table 7 Intermediate Aggregate Requirements Description Test Method Limit Weight of clay lumps, % Max Tex-413-A 0.50 L.A. abrasion wear,1 % Max Tex-410-A 40 5-cycle magnesium sulfate soundness,1,2,3, non -air-entrained concrete, % Max Tex-411-A 25 5-cycle magnesium sulfate soundness,1,2,4, air-entrained concrete, % Max 18 Organic impurities5 Tex-408-A Color not darker than standard Loss by decantation,1 % Max Tex-406-A 1.5 1. Applies only to the portion retained on the No. 4 sieve, if more than 30% of the intermediate aggregate is retained on the No. 4 sieve. 2. Recycled crushed hydraulic cement concrete is not subject to 5- cycle magnesium sulfate soundness requirements. 3. Allowed when air -entrained concrete is used at the Contractor’s option. 4. Only when air -entrained concrete is required by the plans. 5. Applies only to the portion passing the 3/8- in. sieve, if more than 30% of the intermediate aggregate is passing the 3/8-in. sieve. For the portion retained on the No. 4 sieve, if more than 30% of the intermediate aggregate is retained on the No. 4 sieve, and in the case of aggregates made mainly from crushing stone, unless otherwise shown on the plans, the loss by decantation may be increased to 3.0% for all classes of concrete and 5.0% for Class A, B, and P if the material finer than the No. 200 sieve is determined to be at least 85% calcium carbonate in accordance with Tex -406-A , Part III. Provide test results upon request.

2.7 Mortar and Grout . Furnish pre- packaged grouts in accordance with DMS -4675 , “Cementitious Grouts and

Mortars for Miscellaneous Applications,” when specified for applications other than post -tension grouting. When grouting or mortaring stone riprap is shown on the plans, provide mortar and grout consisting of one part hydraulic cement, two parts sand, and sufficient w ater to provide the desired consistency. Other mix proportions allowed as approved. Provide mortar with a consistency such that the mortar can be easily handled and spread by trowel. Provide grout of a consistency that will flow into and completely fill all voids. Section 421.4.2.6., “Mix Design Options,” does not apply for mortar and grout.

2.8 Storage of Mater ials.

2.8.1 Cement and Supplementary Cementitious Materials. Store all cement and supplementary cementitious materials in weatherproof enclosures that will protect the materials from dampness or absorption of moisture.

When permitted, small quantities of packaged cementitious material may be stored in the open, on a raised platform, and under waterproof covering for up to 48 hr.

2.8.2 Aggregates. Handle and store concrete aggregates in a manner that prevents contamination by foreign

materials. Clear and level the sites for the stockpiles of all vegetation if the aggregates are stored on the ground, and do not use the bottom 6-in. layer of aggregate without cleaning the aggregate before use. Maintain separate stockpiles and prevent intermixing when conditions require the use of two or more grades of coarse aggregates. Separate the stockpiles using physical barriers where space is limited. Store aggregates from different sources in different stockpiles unless the Engineer authorizes pre- blending of the aggregates. Minimize segregation in stockpiles. Remix and test stockpiles when segregation is apparent. Sprinkle stockpiles to control moisture and temperature as necessary. Maintain reasonably uniform moisture content in aggregate stockpiles.

2.8.3 Chemical Admixtures. Store admixtures in conformance with manufacturer’s recommendations in tanks that are clearly labeled and prevent admixtures from freezing.

530 3. EQUIPMENT

3.1 Concrete Plants and Mixing Equipment . Except for volumetric stationary plant or truck (auger) mixers,

each plant and truck mixer must be certified by NRMCA or have an inspection report signed and sealed by a licensed professional engineer showing concrete measuring, mixing, and delivery equipment meets all requirements of ASTM C94. A new certification or signed and sealed report is required every time a plant is moved. Plants with a licensed professional engineer’s inspection require re- inspection every 2 yr. Provide a copy of the certification or the signed and sealed inspection report to the Engineer. Remove equipment or facilities from service until corrected when they fail to meet specification requirements. When allowed as shown on the plans or by the Engineer, for concrete classes not identified as structural concrete in Table 8 or for Class C concrete not used for bridge- class structures, the Engineer may inspect and approve all plants and trucks instead of NRMCA or non-Department engineer- sealed certifications. The criteria and frequency of Engineer approval of plants and trucks are the same used for NRMCA cert ification. Inspect and furnish inspection reports of the condition of blades and fins and their percent wear from the original manufacturer’s design for all mixing and agitating equipment annually. Repair mixing equipment exhibiting 10% or more wear before use. If an inspection within 12 mo. is not practical, a 2- mo. grace period (for a maximum of 14 mo. between inspections) is permitted.

3.1.1 Scales. Check all scales before beginning of operations, after each move, or whenever their accuracy or

adequacy is questioned, and at least once every 6 mo. Immediately correct deficiencies, and recalibrate. Provide a record of calibration showing scales in compliance with ASTM C94 requirements. Check batching accuracy of volumetric water batching devices at least every 90 days. Check batching accuracy of chemical admixture dispensing devices at least every 6 mo. Perform daily checks as necessary to ensure measuring accuracy. Check electronic aggregate moisture probes at least every 90 days in accordance with Tex -409-A , and be accurate to within 1.0% of the actual moisture content.

3.1.2 Volumetric Mixers. Provide volumetric mixers with rating plates defining the capacity and the performance

of the mixer in accordance with the Volumetric Mixer Manufacturers Bureau or equivalent. Provide volumetric mixers that comply with ASTM C685. Provide test data showing mixers meet the uniformity test requirements in accordance with Tex -472-A . Unless allowed on the plans or by the Engineer, volumetric truck (auger) mixers may not supply classes of concrete identified as structural concrete in Table 8.

3.1.3 Agitators and Truck and Stationary Mixers. Provide stationary and truck mixers capable of combining the

ingredients of the concrete into a thoroughly mixed and uniform mass and capable of discharging the concrete so that the requirements of Tex -472-A are met. Perform concrete uniformity tests on mixers or agitators in accordance with Tex -472-A as directed, to resolve issues of mix uniformity and mixer performance. Perform the mixer or agitator uniformity test at the full rated capacity of the equipment. Remove all equipment that fails the uniformity test from service. Inspect and maintain mixers and agitators. Keep them free of concrete buildup, and repair or replace worn or damaged blades or fins. Ensure all mixers have a plate affixed showing manufacturer’s recommended operating speed and rated capacity for mixing and agitating. Truck mixers with automated water and chemical admixture measurement and slump and slump flow monitoring equipment meeting the requirement of ASTM C94 will be allowed. Provide data every 6 mo. substantiating the accuracy of slump, slump flow, temperature, water, and chemical admixture measurements. The slump measured by the automated system must be within 1 in. of the slump measured 531 in accordance with Tex -415-A . The concrete temperature measured by the automated system must be within 1°F of concrete temperature measured in accordance with Tex-42 2-A . The Engineer will not use th e automated measurements for acceptance.

3.2 H auling Equipment . Provide hauling equipment capable of maintaining the mixed concrete in a thoroughly

mixed and uniform mass and discharging the concrete with a satisfactory degree of uniformity. Provide equipment with smooth, mortar -tight metal containers equipped with gates that prevent accidental discharge of the concrete when using non-agitating equipment for transporting concrete. Maintain hauling equipment clean and free of built -up concrete.

3.3 Testing Equipm ent. Provide strength- testing equipment when required in accordance with the Contract

controlling test unless shown otherwise. Provide calibration records of strength- testing equipment to the Engineer within 1 week after each calibration. Furnish and maintain the following in conformance with the pertinent test procedure unless otherwise shown on the plans or specified.  Test molds  Curing facilities  Maturity meters if used  Wheelbarrow or other container acceptable for the sampling of the concrete

4.1 Classification of Concrete Mix Designs. Provide classes of concrete meeting the requirements shown in Table 8.

A higher -strength class of concrete with equal or lower water -to-cementitious material (w/cm) ratio may be substituted for the specified class of concrete when approved.

4.2 Mix Design Proportioning. Furnish mix designs using ACI 211, Tex -470-A , or other approved procedures

for the classes of concrete shown in Table 8 unless a design method is shown on the plans. Perform mix design proportioning by absolute volume method unless otherwise approved. Perform cement replacement using equivalent weight method unless otherwise approved. Do not exceed the maximum w/cm ratio shown i n Table 8 when designing the mixture.

4.2.1 Cementitious Materials. Do not exceed 700 lb. of cementitious material per cubic yard of concrete unless

otherwise specified or approved.  Use cement of the same type and from the same source for monolithic placements, unless otherwise approved.  Do not use SCMs when white hydraulic cement is specified.

4.2.2 Aggregates. Recycled crushed hydraulic cement concrete may be used as a coarse or fine aggregate in

Class A, B, E, and P concrete. Limit recycled crushed concrete fine aggregate to at most 20% of the fine aggregate. Use light -colored aggregates when white hydraulic cement is specified. 532 Table 8 Concrete Classes Class of Concrete Design Strength1, Min f′c (psi) Max w/cm Ratio Cement Types Mix Design Options Exceptions to Mix Design Options General Use2 A 3,000 0.60 I, II, I/II, IL, IP, IS, IT, V 1, 2, 4, and 7 When the cementitious material content does not exceed 520 lb./cu. yd.., any coal ash or natural pozzolan listed in the MPL may be used at a cement replacement of 20%–50%. Limit the alkali loading to 4.0 lb./cu. yd. or less when using Option 7. Curb, gutter, curb and gutter, concrete retards, sidewalks, driveways, backup walls, anchors, non-reinforced drilled shafts B 2,000 0.60Riprap, traffic signal controller foundations, small roadside signs, anchors C3 3,600 0.45 I, II, I/II, IP, IL, IS, IT, V 1–8 N/A Drilled shafts, bridge substructure, traffic rail, culverts except top slab of direct traffic culverts, headwalls, wing walls, inlets, manholes, traffic barrier E 3,000 0.50 I, II, I/II, IL, IP, IS, IT, V 1–8 When the cementitious material content does not exceed 520 lb./cu. yd., any coal ash or natural pozzolan listed on the MPLs may be used at a cement replacement of 20%–50%. Limit the alkali loading to 4.0 lb./cu. yd. or less when using Option 7. Seal concrete F3 Note4 0.45 I, II, I/II, IP, IL, IS, IT, V N/A Railroad structures; occasionally for bridge piers, columns, bents, post-tension members H3 Note4 0.45 I, II, I/II, III, IP, IL, IS, IT, V 1–4, 8 Mix design Options 1–8 allowed for cast-in-place concrete and the following precast elements unless otherwise shown on the plans.  Bridge deck panels  Retaining wall systems  Coping  Sound walls  Wall columns  Traffic rail  Traffic barrier  Long/arch-span culverts  Precast concrete products in accordance with Item 462, 464, and 465 Do not use Type III cement in mass placement concrete. Precast concrete, post-tension members S3 4,000 0.45 I, II, I/II, IP, IL, IS, IT, V 1–8 N/A Bridge slabs, top slabs of direct traffic culverts, approach slabs P See Item 360, “Concrete Pavement.” 0.50 I, II, I/II, IL, IP, IS, IT, V 1–8 When the cementitious material content does not exceed 520 lb./cu. yd., any coal ash or natural pozzolan on the MPLs may be used at a cement replacement of 20% –50%. Concrete pavement 533 Class of Concrete Design Strength1, Min f′c (psi) Max w/cm Ratio Cement Types Mix Design Options Exceptions to Mix Design Options General Use2 CO3 4,600 0.40 I, II, I/II, IP, IL, IS, IT, V 1–8 N/A Bridge deck concrete overlay LMC3 4,000 0.40 Latex-modified concrete overlay SS3 3,600 0.45 1–8 Use a minimum cementitious material content of 658 lb./cu. yd. of concrete. Limit the alkali loading to 4.0 lb. per cubic yard or less when using Option 7. Slurry displacement shafts, underwater drilled shafts K3 Note4 0.40 I, II, I/II, III, IP, IL, IS, IT, V 1–8 N/A Bridge repair HES Note4 0.45 I, IL, II, I/II, III N/A Mix design options do not apply. Limit of 700 lb. of cementitious material per cubic yard is not pertinent. Concrete pavement, concrete pavement repair “X” (HPC)3,5,6 Note7 0.45 I, II, I/II, III, IP, IL, IS, IT, V 1–4, and 8 N/A N/A “X” (SRC)3,5,6 Note7 0.45 I/II, II, IP, IL (MS or HS), IS, IT (MS or HS), V 1–4, and 7 When using coal ash, use only coal ashes allowed for SRC in accordance with the coal ash MPL. Type III-MS may be used where allowed. Type I, Type IL, and Type III cements may be used when natural pozzolans are used or when coal ashes allowed for SRC in accordance with the coal ash MPL are used, and with a Max w/cm of 0.40. Use Option 7 for precast concrete where allowed. N/A 1. Design strength must be attained within 56 days. 2. For information only. 3. Structural concrete classes. 4. As shown on the plans or specified. 5. “X” denotes class of concrete as shown on the plans or specified. 6. (HPC): High Performance Concrete, (S RC): Sulfate Resistant Concrete. 7. Same as class of concrete as shown on the plans. 4.2.2.1. Coarse Aggregate. Use Grade 2 or 3 coarse aggregate for Class P concrete. Use Grade 8 aggregate in extruded curbs unless otherwise approved. Unless other wise specified, do not use Grade 1 aggregate in drilled shafts. Use coarse aggregate gr ades for all other classes of concre te with a maximum nominal size no larger than:  1/5 the narrowest dimension between sides of forms;  1/3 the depth of slabs;  2/3 the minimum clear spacing between individual rein forcing bars or wire, bundles of bars, individual tendons, bundles of tendons, or ducts for cast-in-place concrete; or  3/4 the minimum clear spacing between individual rein forcing bars or wires, bundles of bars, individual tendons, bundled tendons, or ducts for precast concrete. 4.2.2.2. Fine Aggregate . Use fine aggregate with an acid insoluble residue of at least 60% by weight when tested in accordance with Tex-612-J in all concrete subject to direct traffic. Use the following equation to determine whether the aggregate combination meets the acid insoluble residue requirement when blending fine aggregate or using an intermediate aggregate. 534 ( ) ( ) ( )% 601002 2 1 1≥× + × + ×ia iaP A P A P A where: A1 = acid insoluble (%) of fine aggregate 1 A2 = acid insoluble (%) of fine aggregate 2 Aia = acid insoluble (%) of intermediate aggregate passing the 3/8 in. sieve P1 = percent by weight of fine aggregate 1 of the fine aggregate blend P2 = percent by weight of fine aggregate 2 of the fine aggregate bl end Pia = percent by weight of intermediate aggregate passing the 3/8- in. sieve Alternatively to the above equation, blend fine aggregate with a Micro- Deval loss of less than 12%, when tested in accordance with Tex -461-A , with at least 40% of a fine aggregate with an acid insoluble residue of at least 60%. Use the following equation to determine whether the aggregate combination meets the sand equivalency requirement when blending fine aggregate or using an intermediate aggregate. ( ) ( ) ( )% 80 1002 2 1 1≥× + × + ×ia iaP SE P SE P SE where: SE1 = sand equivalency (%) of fine aggregate 1 SE2 = sand equivalency (%) of fine aggregate 2 SEia = sand equivalency (%) of intermediate aggregate passing the 3/8 in. sieve P1 = percent by weight of fine aggregate 1 of the fine aggregate blend P2 = percent by weight of fine aggregate 2 of the fine aggregate blend Pia = percent by weight of intermediate aggregate passing the 3/8- in. sieve

4.2.3 Chemical Admixtures. Do not use Type C, E, F, or G admixtures in Class S bridge deck concrete. Do not

use chemical admixtures containing calcium chloride in any concrete. Use a 30% calcium nitrite solution when a corrosion- inhibit ing admixture is required. Dose the admixture at the rate of gallons of admixture per cubic yard of concrete shown on the plans. Use set retarding admixtures, as needed, to control setting time to ensure concrete containing corrosion inhibiting admixtures remains workable for the entire duration of the concrete placement. Perform setting time testing and slump loss tests during trial batch testing.

4.2.4 Air Entrainment . When air -entrained concrete is shown on the plans, target an entrained air content of 4.0%

for Class P concrete and 5.5% for all other classes of concrete. Use an approved air -entraining admixture when air -entrained concrete is specified, or when an air -entraining admixture is used at the Contractor’s option. Unless otherwise shown on the plans, acceptance of concrete loads will be based on a tolerance of ±1.5% from the target air content. If the air content is more than 1.5 but less than 3.0% above the target air, the concrete may be accepted based on strength tests. For specified concrete strengths above 5,000 psi, a reduction of 1% entrained air content is permitted.

4.2.5 Slump . Provide concrete with a slump in accordance with Table 9 unless otherwise specified. When

approved, the slump of a given concrete mix may be increased above the values shown in Table 9 using chemical admixtures, provided the admixture- treated concrete has the same or lower w/cm ratio and does not exhibit segregation or excessive bleeding. Request approval to exceed the slump limits shown in Table 9 sufficiently in advance for proper evaluation by the Engineer. 535 Table 9 Placement Slump Requirements General Use Placement Slump Range (in.) Walls (>9 in. thick), caps, columns, piers 3–7 Bridge slabs, top slabs of direct traffic culverts, approach slabs, concrete overlays 3–6 Latex -modified concrete for bridge deck overlays 3–8 Inlets, manholes, walls (<9 in. thick), bridge railing, culverts, concrete traffic barrier, concrete pavement (formed) 4–6 Precast concrete 4–9 Underwater concrete placements 6–8-1/2 Drilled shafts, slurry displaced, underwater drilled shafts See Item 416, “Drilled Shaft Foundations” Curb, gutter, curb and gutter, concrete retards, sidewalk, driveways, seal concrete, anchors, riprap, small roadside sign foundations, concrete pavement repair, concrete repair As approved

4.2.6 Mix Design Options .

4.2.6.1. Option 1 . Replace cement with at least the minimum dosage listed on the MPL for the coal ash or natural pozzolan used in the mixture. Conduct Option 8 testing to determine the minimum replacement dosage as listed on the MPL. Do not replace more than 50% of the cement. Up to 70% of the cement may be replaced when concrete is used for mass concrete placements. 4.2.6.2. Option 2 . Replace 35–50% of the cement with slag cement. Up to 70% of the cement may be replaced when concrete is used for mass concrete placements. 4.2.6.3. Option 3 . Replace 35–50% of the cement with a combination of coal ash, slag cement, MFA, natural pozzolan, or at least 3% silica fume; however, no more than 10% may be silica fume. Up to 70% of the cement may be replaced when concrete is used for mass concrete placements. 4.2.6.4. Option 4 . Use Type IP, IS, or IT cement as allowed in Table 8 for each class of concrete. When replacing blended cements with additional SCMs, the replacement limits in Option 3 will apply to the final cementitious mixture. When using fly ash or natural pozzolans not having a minimum dosage listed on the MPL in the final cement itious mixture, perform Option 8 testing. 4.2.6.5. Option 5 . Option 5 is left intentionally blank. 4.2.6.6. Option 6 . Use a lithium nitrate admixture at a minimum dosage determined by testing conducted in accordance with Tex -471-A . Before use of the mix, provide an annual certified test report signed and sealed by a licensed professional engineer, from a laboratory on the MPL, certified by the Materials and Tests Division (MTD) as being capable of testing in accordance with Tex-471-A . 4.2.6.7. Option 7 . Ensure the total alkali contribution from the cement in the concrete does not exceed 3.5 lb. per cubic yard of concrete when using hydraulic cement not containing SCMs calculated as follows . ( )( ) 100cement in equivalent Ο2Na % yd. cu. per cement lb. yd. cu. per alkali lb.× = In the above calculation, use the maximum cement alkali content reported on the cement mill certificate. 4.2.6.8. Option 8 . Use Table 10 when deviating from Options 1– 3 or when required by the coal ash MPL. Perform required testing annually and submit results to the Engineer. Laboratories performing ASTM C1260, C1567, and C1293 testing must be listed on the Department’s MPL. Before use of the mix, provide a certified test report signed and sealed by a licensed professional engineer demonstrating the proposed mixture conforms to the requirements of Table 10. 536 Provide a certified test report signed and sealed by a licensed professional engineer, when high- performance concrete (HPC) is required, and less than 20% of the cement is replaced with SCMs, demonstrating ASTM C1202 test results indicate the permeability of the concrete is less than 1,500 coulombs tested immediately after either of the following curing schedules.  Moisture cure specimens 56 days at 73°F.  Moisture cure specimens 7 days at 73°F followed by 21 days at 100°F. Table 10 Option 8 Testing and Mix Design Requirements Scenar io ASTM C1260 Result Testing Requirements for Mix Design Materials or Prescriptive Mix Design Options1 Mix Design Fine Aggregate Mix Design Coarse Aggregate A >0.10% >0.10% Determine the dosage of SCMs needed to limit the 14 -day expansion of each aggregate1 to <0.10% when tested individually in accordance with ASTM C1567. B ≤0.10% ≤0.10% Use the minimum replacement listed in the coal ash MPL, or When Option 8 is listed on the MPL, use at least 40% coal ash with a maximum CaO2 content of 25%, or Use any ternary combination that replaces 35 –50% of cement. ≤0.10% ASTM C1293 1 yr. Expansion ≤0.04% Use a minimum of 20% of any coal ash; or Use any ternary combination that replaces 20 –50% of cement. C ≤0.10% >0.10% Determine the dosage of SCMs needed to limit the 14 -day expansion of course and intermediate1 aggregate to <0.10% when tested individually in accordance with ASTM C1567. D >0.10% ≤0.10% Use the minimum replacement listed in the coal ash MPL, or When Option 8 is listed i n the MPL, use a minimum of 40% coal ash with a maximum CaO2 content of 25%, or Use any ternary combination that replaces 35% to 50% of cement. > 0.10% ASTM C1293 1 yr. Expansion ≤ 0.04% Determine the dosage of SCMs needed to limit the 14 -day expansion of each fine aggregate to <0.10% when individually tested in accordance with ASTM C1567. 1. Intermediate size aggregates will fall under the requirements of mix design coarse aggregate. 2. Average the CaO content from the previous ten values as listed on the test certificate.

4.2.7 Optimized Aggregate Gradation (OAG) Concrete . The gradation requirements shown in Table 4 and

Table 6 do not apply when OAG concrete is specified or used by the Contractor, unless otherwise shown on the plans. The fineness modulus for fine aggregate shown in Table 5 does not apply when OAG concrete is used. Establish the optimized aggregate gradation in accordance with T ex-470-A . Use at least 420 lb. per cubic yard of cementitious material when OAG concrete is used unless otherwise approved. Make necessary adjustments to individual aggregate stockpile proportions during OAG concrete pro duction when the gradation deviates more than 2% from the optimized gradation requirements.

4.2.8 Self-Consolidating Concrete (SCC) . Provide SCC meeting the requirements shown in Table 11 when

approved for use in precast concrete. Use concrete with a slump flow that can be placed without vibration and will not segregate or excessively bleed. Request approval to exceed the slump flow limits sufficiently in advance for proper evaluation by the Engineer. 537 Table 11 Mix Design Requirements for SCC Tests Test Method Acceptable Limits Slump flow for precast concrete ASTM C1611 22–271 T50, sec. ASTM C1611 2–7 VSI rating ASTM C1611 0 or 1 Passing ability, in. ASTM C1621 ≤2 Segregation column, % ASTM C1610 ≤10 Bleeding, % ASTM C232 ≤2.5 1. These slump flow limits are generally acceptable for most applications. However, slump flow limits may be adjusted during mix design approval process and when approved.

4.3 Concrete Trial Batches. Perform trial batches when required by the plans, or when previous satisfactory

field data is not available. Submit previous satisfactory field data to the Engineer showing the proposed mix design conforms to specification requirements when trial batches are not required and before concrete is placed. Trial batch test results will be reported to the Contractor and the concrete supplier. Trial batches are not required for Class A, B, or E concrete unless establishing target values as described below. Perform trial batches for all self -consolidating concrete mix designs. Make all trial batches using the proposed ingredients in a mixer that is representative of the mixers to be used on the project when required. Make the batch size at least 50% of the mixer’s rated capacity. Alternatively, use an AASHTO -accredited laboratory to perform laboratory trial batches using all the proposed ingredients. Perform fresh concrete tests for air content and slump, and make, cure, and test strength specimens for compliance with specification requirements. Test at least one set of design strength specimens, consisting of two specimens per set, at 7- day, 28- day, and at least one additional age unless otherwise directed. Before placing, provide the Engineer the option of witnessing trial batches, including the testing of the concrete. If not provided this option, the Engineer may require additional trial batches, including testing, before the concrete is placed. Trial batches for precast concrete will be performed in accordance with Tex -703-I to show proposed mix design meets the requirements of the pertinent class of concrete, or Table 11 when SCC is used. Establish a compressive strength target value in accordance with Tex-427-A for each Class A, B, and E concrete. When changes are made to the type, brand, or source of aggregates, cement, SCM, w ater, or chemical admixtures, submit previous satisfactory field data, data from a new trial batch, or other evidence showing the change will not adversely affect the relevant properties of the concrete. Submit the data for approval before making changes to the mix design. A change in vendor does not necessarily constitute a change in materials or source. The Engineer may waive new trial batches when there is a prior record of satisfactory performance with the ingredients. During concrete production, dosage changes of chemical admixtures used in the trial batches will not require a re- evaluation of the mix design . The Contractor has the opt ion of performing trial batches in conjunction with concrete placements except for SCC mixtures, when new trial batches are required during the course of the project. If the concrete fails to meet any requirement, the Engineer will determine acceptability and payment adjustments. Establishing target strength for Class A, B, and E concrete may be conducted during these placements. Establish the strength–maturity relationship in accordance with Tex -426-A when the maturity method is specified or permitted. When using the maturity method, any changes in any of the ingredients, including changes in proportions, will require the development of a new strength– maturity relationship for the mix .

4.3.1 Mix Design of Record . Once a trial batch or previously satisfactory field data substantiates the mix design,

the proportions and mixing methods used become the mix design of record. Do not exceed mix design w/cm ratio. 538 4.4. Production Testing.

4.4.1 Aggregate Moisture Testing. Deter mine moisture content in accordance with Tex -409-A or Tex-425-A for

coarse, intermediate, and fine aggregates at least twice per week, when there is an apparent change, or for new shipments of aggregate. When aggregate hoppers or storage bins are equipped with properly maintained electronic moisture probes for continuous moisture determination, moisture tests in accordance with Tex-409-A or Tex-425-A are not required. When producing SCC, and when aggregate hoppers or storage bins are not equipped with electronic moisture probes, determine the moisture content of the aggregates before producing the first concrete batch each day. Thereafter, determine the moisture content every 4 hr. or when there is an apparent change while SCC is being produced.

4.4.2 Aggrega te Gradation Testing. Perform a sieve analysis in accordance with Tex -401-A on each stockpile

used in the blend at least 1 day before producing OAG concrete. Perform sieve analysis on each stockpile after every 10,000 cu. yd. of Class P OAG concrete produced, and every 1,000 cu. yd. for all other structural -class concrete. Provide sieve analysis data to the Engineer.

4.5 Measurement of Materials.

4.5.1 Non-Volumetric Mixers. Measure aggregates by weight. Correct batch weight measurements for aggregate

moisture content. Measure mixing water, consisting of water added to the batch, ice added to the batch, water occurring as surface moisture on the aggregates, and water introduced in the form of admixtures, by volume or weight. Measure ice by weight. Measure cement and SCMs in a hopper and on a separate scale from those used for other materials. When measuring by cumulative weight, measure the cement first and ensure the cement meets the cement tolerance shown in Table 12 before measuring the SCMs . Measure concrete chemical admixtures by weight or volume. Measure batch materials within the tolerances shown in Table 12. Table 12 Mix Design Batching Tolerances— Non-Volumetric Mixers Material Tolerance (%) Cement, wt. ˗1 to +3 SCM, wt. ˗1 to +3 Cement + SCM (cumulative weighing), wt. ˗1 to +3 Water, wt. or volume ±31 Fine aggregate, wt. ±2 Coarse aggregate, wt. ±2 Fine + coarse aggregate (cumulative weighing), wt. ±1 Chemical admixtures, wt. or volume ±3 1. Allowable deviation from target weight, not including water withheld or moisture in the aggregate. The Engineer will verify the w/cm ratio is within specified limits. Ensure the quantity measured, when measuring cementitious materials at less than 30% of scale capacity, is accura te to no less than the required amount and no more than 4% in excess. Ensure the cumulative quantity, when measuring aggregates in a cumulative weigh batcher at less than 30% of the scale capacity, is measured accurately to ±0.3% of scale capacity or ±3% of the required cumulative weight, whichever is less. Measure cement in number of bags under special circumstances when approved. Use the weights specified on the packaging. Weighing bags of cement is not required. Ensure fractional bags are not used except for small hand- mixed batches of approximately 5 cu. ft. or less and when an approved method of volumetric or weight measurement is used.

4.5.2 Volumetric Mixers. Provide an accurate method of measuring all ingredients by volume and calibrate equipment to assure correct measurement of materials within the specified tolerances. Base tolerances on

volume- weight relationship established by calibration and measure the various ingredients within the tolerances shown in Table 13. Correct batch measurements for aggregate moisture content. 539 Table 13 Mix Design Batching Tolerances— Volumetric Mixers Material Tolerance Cement, wt. % 0 to +4 SCM, wt. % 0 to +4 Fine aggregate, wt. % ±2 Coarse aggregate, wt. % ±2 Admixtures, wt. or volume % ±3 Water, wt. or volume % ±1

4.6 Mixing and Delivering Concrete .

4.6.1 Mixing Concrete . Operate mixers and agitators within the limits of the rated capacity and speed of rotation

for mixing and agitation as designated by the manufacturer of the equipment. Provide concrete in a thoroughly mixed and uniform mass with a satisfactory degree of uniformity when tested in accordance with Tex-472-A . Do not top- load new concrete onto returned concrete. Adjust mixing times and batching operations as necessary when the concrete contains silica fume to ensure the material is completely and uniformly dispersed in the mix. The dispersion of the silica fume within the mix will be verified by MTD using cylinders made from trial batches. Make necessary changes to the batching operations, if uniform dispersion is not achieved, until uniform and complete dispersion of the silica fume is achieved. Mix concrete by hand methods or in a small motor -driven mixer when permitted, for small placements of less than 2 cu. yd. For such placements, proportion the mix by volume or weight.

4.6.2 Delivering Concrete. Deliver concrete to the project in a thoroughly mixed and uniform mass, and discharge the concrete with a satisfactory degree of uniformity. Conduct testing in accordance with Tex -472-A

when there is a reason to suspect the uniformity of concrete and as directed. Maintain concrete delivery and placement rates sufficient to prevent cold joints. Adding chemical admixtures or the portion of water withheld is permitted only at the jobsite, under the supervision of the Engineer, to adjust the slump or slump flow of the concrete. Do not add water or chemical admixtures to the batch after more than an amount needed to conduct slump testing has been discharged. Turn the drum or blades at least 30 additional revolutions at mixing speed to ensure thorough and uniform mixing of the concrete. When this water is added, do not exceed the approved mix design w/ cm ratio. When truck mixers are equipped with automated water or chemical admixture measurement and slump or slump flow monitoring equipment, the addition of water or chemical admixtures during transit is allowed. Reports generated by this equipment must be submitted to the Engineer daily. Before unloading, furnish the delivery ticket for the batch of concrete containing the information required in accordance with ASTM C94. The Engineer will verify all required information is provided on the delivery tickets. The Engineer may suspend concrete operations until the corrective actions are implemented if delivery tickets do not provide the required information. The Engineer will verify the design w/cm ratio is not exceeded. An electronic ticket delivery system (e -ticketing) may be used instead of printed tickets. The use of e -ticketing will require written approval. At minimum, the system will:  provide electronic, real -time e -tickets meeting the requirements above;  automatically generate e- tickets using software and hardware fully integrated with the batch plant scales used to weigh the material; 540  be able to record all water and chemical admixture additions performed at the jobsite or in transit when allowed;  provide the ability to associate fresh concrete test results with each e-ticket;  be designed in such a way that data input cannot be altered by the Contractor or the Engineer;  provide the Engineer access to the e- ticketing data in real -time using a web- based or app- based system compatible with iOS; and  provide offline capabilities to prevent data loss if power or connectivity is lost. The Engineer may discontinue use of the e- ticketing and require printed tickets as needed if the e- ticketing system fails to meet the above requirements. Begin the discharge of concrete delivered in truck mixers within the times shown in Table 14. Concrete delivered after these times and concrete that has not begun to discharge within these times will be rejected. The discharge times shown in Table 14 may be extended provided slump loss testing is conducted in accordance with Tex -430-A to show concrete will maintain the minimum required slump for the requ ested discharge time extension. Extended discharge times will be allowed when the concrete temperature at time of discharge is no more than 10°F higher than the slump loss test concrete temperature. Table 14 Concrete Discharge Times for Truck Mixers Fresh Concrete Temperature, °F Max Time After Batching for Concrete Not Containing Type B or D Admixtures, min. Max Time After Batching for Concrete Containing Type B or D Admixtures,1 min. 90 and above 45 75 75 ≤T <90 60 90 T <75 90 120 1. Concrete must contain at least the minimum manufacturer’s recommended dosage of Type B or D admixture.

4.7 Placing, Finishing, and Curing Concrete . Place, finish, and cure concrete in conformance with the

pertinent Items.

4.8 Sampling and Testing of Concrete . Unless otherwise specified, a ll fresh and hardened concrete is subject

to testing as follows.

4.8.1 Certification of Testing Personnel . Contractor personnel performing testing must be either ACI -certified or

qualified by a Department -recognized equivalent written and performance testing program for the tests being performed. Personnel performing these tests are subject to Department approval. Use of a commercial laboratory is permitted at the Contractor’s option.

4.8.2 Fresh Concrete . Provide safe access and assistance to the Engineer during sampling. Fresh concrete will

be sampled for testing at the point of discharge from the delivery equipment or end of belt conveyors.

4.8.3 Testing Concrete . The Engineer, unless specified in other Items or shown on the plans, will test the fresh

and hardened concrete in accordance with the following methods.  Slump . Tex-415-A  Air Content . Tex-414-A or Tex-416-A, only when air -entrained concrete is shown on the plans  Temperature. Tex -422-A  Making and Curing Streng th Specimens. Tex -447-A  Compressive Strength . Tex-418-A  Flexural Strength . Tex-448-A  Maturity . Tex-426-A Flexural strength and maturity specimens will not be made unless specified in other Items or shown on the plans . 541 Concrete with slump less than minimum required after all addition of water withheld will be rejected, unless otherwise allowed by the Engineer. Concrete with slump exceeding maximum allowed may be used at the Contractor’s option. If used, Engineer will make, test, and evaluate strength specimens in accordance with Article 421.5., “Acceptance of Concrete.” Acceptance of concrete not meeting air content or temperature requirements will be determined by Engineer. Fresh concrete exhibiting segregation and excessive bleeding will be rejected. 4.8.3.1. Strength Specimen Handling. After strength test specimens are molded, protect and cure in conformance with pertinent test methods. When necessary, deliver Contractor -molded specimens to curing facilities, remove specimens from their molds, and place specimens in curing tanks within 24–48 hr. after molding, in conformance with pertinent test methods. The Engineer will deliver Department -molded specimens to curing facilities, remove specimens from their molds, and place specimens in curing tanks within 24–48 hr. after molding, in conformance with pertinent test methods.

5.1 Structural Class of Concrete. For concrete classes identified as structural concrete shown in Table 8, the

Engineer will make and test 7-day and 28- day specimens, and, if necessary, 56- day specimens. The Engineer will base acceptance on attaining the design strength shown in Table 8 or design strength shown on the plans.

5.2 Class P and Class High Early Strength (HES). The Engineer will base acceptance in accordance with

Item 360 and Item 361, “Repair of Concrete Pavement.”

5.3 All Other Classes of Concrete. For concrete classes not identified as structural concrete in Table 8, the

Engineer will make and test 7- day specimens. The Engineer will base acceptance on attaining design strength or attaining the 7- day target value established in accordance with Tex -427-A .