51-03300 Cast in Place.pdf

SECTION 03300

CAST-IN-PLACE CONCRETE DIVISION 3

West Branch Regional Authority 03300-1 January 2026 Route 54 Sanitary Sewer Extension Project Cast-in-Place Concrete Contract No. WB-1

PART 1 - GENERAL

1.01 SECTION INCLUDES

A. Production, transportation, placement, finishing, and curing of Portland cement concrete.

B. Concrete repairs.

C. Admixtures.

D. Vapor barrier.

1.02 RELATED SECTIONS

A. Section 03200: Concrete Reinforcement.

1.03 REFERENCES

A. American Association of State Highway and Transportation Officials (AASHTO).

1. AASHTO M43 - Standard Sizes of Coarse Aggregate for Highway Construction.

2. AASHTO M80 - Coarse Aggregate for Portland Cement Concrete.

3. AASHTO M182 - Burlap Cloth Made from Jute or Kenaf.

B. American Concrete Institute (ACI)

1. ACI 211.1 - Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete.

2. ACI 301 - Specifications for Structural Concrete for Buildings.

3. ACI 304R - Guide for Measuring, Mixing, Transporting, and Placing Concrete.

4. ACI 305R - Hot Weather Concreting.

5. ACI 306R - Cold Weather Concreting.

6. ACI 309R - Guide for Consolidation of Concrete.

C. American Society for Testing and Materials (ASTM)

1. ASTM C31 - Making and Curing Concrete Test Specimens in the Field.

2. ASTM C33 - Concrete Aggregates.

3. ASTM C39 - Compressive Strength of Cylindrical Concrete Specimens.

4. ASTM C42 - Obtaining and Testing Drilled Cores and Sawed Beams of Concrete.

5. ASTM C94 - Ready-Mixed Concrete.

6. ASTM C138 - Unit Weight, Yield, and Air Content of Concrete.

7. ASTM C143 - Slump of Portland Cement Concrete.

8. ASTM C150 - Portland Cement.

9. ASTM C171 - Sheet Materials for Curing Concrete.

10. ASTM C172 - Sampling Freshly Mixed Concrete.

11. ASTM C173 - Air Content of Freshly Mixed Concrete by the Volumetric Method.

12. ASTM C231 - Air Content of Freshly Mixed Concrete by the Pressure Method.

13. ASTM C233 - Testing Air Entraining Admixtures for Concrete.

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14. ASTM C260 - Air Entraining Admixtures for Concrete.

15. ASTM C309 - Liquid Membrane - Forming Compounds for Curing Concrete.

16. ASTM C494 - Chemical Admixtures for Concrete.

17. ASTM E1155 - Determining Floor Flatness and Levelness Using the “F-Number”

System.

1.04 DEFINITIONS

A. Coarse Aggregate: Aggregate within the range of 3/16-inch to 3-inches.

B. Fine Aggregate: Aggregate with maximum particle size of 3/16-inch.

1.05 SUBMITTALS

A. Submit required data and samples under provisions of Section 01340: Shop Drawings, Product Data and Samples.

B. Submit within sixty (60) days of Commencement of Contract Time, a detailed report on the proposed mix designs. Include the following:

1. For cement and each aggregate size range:

a. Source

b. Type

c. Test results showing that materials meet these Specifications

2. Air-Entraining Agent: Test report in accordance with ASTM C233.

3. Other Admixtures: Test report in accordance with ASTM C494.

4. For each concrete mix design:

a. Weight of cement, water, coarse aggregate, and fine aggregate in each cubic yard.

b. Slump (ASTM C143).

c. Air Content (ASTM C138).

d. Compressive strength at seven (7) and twenty-eight (28) days (ASTM

C39).

e. Unit weight and yield (ASTM C138).

5. Quantity of admixtures (test admixtures in combination with materials described in the mix design report).

C. Submit Product data for curing and sealing compound, hardening compound, epoxy bonding adhesive, vapor barrier, and stair tread safety nosing.

D. Submit a delivery ticket from the concrete supplier for each load delivered to the job site.

At a minimum, each delivery ticket shall include the following information:

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1. Date

2. Name of purchaser

3. Number of truck and driver's name

4. Class of concrete

5. Slump ordered

6. Amount of concrete in truck

7. Amount of cement in batch

8. Amount of water in batch

9. Type and amount of admixtures used

10. Maximum aggregate size

11. Time concrete mixing started

12. Time of discharge at job site

1.06 QUALITY ASSURANCE

A. Perform work in accordance with ACI 301, except when these Specifications contain more stringent requirements.

B. Obtain cement and aggregates from same source for all work.

C. Conform to ACI 305R when concreting during hot weather, except when these

Specifications contain more stringent requirements.

D. Conform to ACI 306R when concreting during cold weather, except when these

Specifications contain more stringent requirements.

PART 2 - PRODUCTS

2.01 CONCRETE MATERIALS

A. Cement: ASTM C150, Type II.

B. Fine and Coarse Aggregates

1. Fine Aggregate: Meet requirements of ASTM C33.

2. Coarse Aggregate: Meet requirements of AASHTO M80, Class A.

3. Do not use aggregates containing spall-causing particles.

4. In Class A concrete, limit amount of long sliver-like and flat pieces to fifteen percent (15%) of total aggregate volume.

C. Water: Potable quality, clean and free of visible suspended matter.

2.02 ADMIXTURES

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A. Air-Entraining

1. ASTM C260

2. Acceptable Manufacturers

a. Sika AER

b. Master Builders Micro-Air

c. EUCO Air-Mix

B. Water-Reducing Admixture

1. ASTM C494, Type A

a. Sika Plastocrete 161

b. Master Builders Pozzolith N

c. EUCO Eucon WR-75

C. High-Range Water-Reducing Admixture (super plasticizer)

1. ASTM C494, Type F or G

a. Sika Sikament 300

b. Master Builders Rheobuild

c. EUCO Eucon - 37

D. Water-Reducing Accelerator Admixture

1. ASTM C494, Type E

a. Sika Plastocrete 161FL

b. EUCO Accelguard 80

E. Water-Reducing, Retarding Admixture

1. ASTM C494, Type D

a. Sika Plastiment

b. Master Builders Pozzolith R

c. EUCO Retarder - 75

F. Prohibited Admixtures

1. Calcium chloride thyocynates or admixtures containing more than 0.1% percent chloride ions.

2. Fly ash.

2.03 ACCESSORIES

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A. Curing and Sealing Compound

1. ASTM C309, Type 1, Class A or B.

2. Suitable for use as curing compound, surface sealer, and dustproofer.

3. Suitable for indoor or outdoor use.

4. Acceptable Manufacturers:

a. L and M Dress and Seal #18

b. Master Builders MB-429

c. EUCO Rez-Seal

B. Curing and Hardening Compound

1. Suitable for use as sprayable curing compound, floor sealer, dustproofer, and hardener.

2. Acceptable Manufacturers:

a. L&M Chem Hard

b. Siko Sikagard 655, Cure/Hard

c. EUCO Eucosil

C. Epoxy Bonding Adhesive

1. Suitable for use in bonding freshly mixed concrete or grout to hardened concrete:

a. For surface repairs

b. In applying an overlay to an interior slab

2. Suitable for use when concrete surface is damp.

3. Not for use in load-bearing applications. Consult Engineer to determine bonding agent requirements for load-bearing applications.

4. Acceptable Manufacturers:

a. Sika Sikadur 32 Hi-Mod

b. EUCO #452

c. L and M Epobond

D. Moisture-Absorptive Curing Cloth

1. AASHTO M182

2. Burlap cloth made from jute or kenaf

E. Moisture-Retaining Curing Fabric

1. ASTM C171

2. Waterproof paper, polyethylene film, or burlap-polyethylene sheet

F. Vapor Barrier

1. Seven-ply polyethylene reinforced with nylon

2. Acceptable Manufacturer: Griffolyn T-85

G. Stair Tread Safety Nosing

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1. Cross-hatched abrasive cast aluminum, four inches wide

2. Acceptable Manufacturers:

a. American Safety Tread Company

b. American Abrasive Metals Company

c. Wooster Products, Inc.

H. Joint Sealants: approved by the Engineer

2.04 CONCRETE MIXES

A. Prepare mix design for each class and type of concrete in accordance with ACI 211.1.

B. Class: All concrete used on the Project shall fall into one (1) of the following compressive strength classes:

1. Class A: Minimum 4,000 psi compressive strength at 28 days.

2. Class B: Minimum 3,000 psi compressive strength at 28 days.

3. Class C: Minimum 2,500 psi compressive strength at 28 days.

C. Water/Cement Ratio

1. For all Class A Concrete: 0.44 to 0.45.

2. For Class B Concrete which will be subjected to freezing and thawing: Maximum

0.50.

3. For concrete which will be subjected to deicing chemicals: Maximum 0.45.

4. For all other concrete, compressive strength requirement will control water/cement ratio.

D. Coarse Aggregate Gradation

1. Class A Concrete

a. For walls and slabs: 1 1/2-inch maximum size; AASHTO M43, Size 467.

b. For beams, columns, and thin walls and slabs:

1) Maximum size aggregate (MSA) will be limited to the smallest of the following three (3) dimensions:

a) 1/5 times the smallest dimension between interior form faces.

b) 1/3 times the depth of slabs.

c) 3/4 times the minimum clear spacing between individual reinforcing bars or wires.

2) Use AASHTO M43, Size 467 aggregate when the MSA determined in 2.04D1b (1) above is equal to or greater than 1 1/2 inches.

3) When the MSA determined in 2.04D1b(1) above is less than 1 1/2 inches, use AASHTO M43, Size 57 or 67. Use Size 57 when MSA is computed to be greater than 3/4 inch. Use Size

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67 when MSA is computed to be equal to or less than 3/4 inch.

2. Class B and C Concrete: Determine MSA by means of criteria given in 2.04D1b

(1) above.

E. Air Entrainment

1. Class A Concrete

a. For AASHTO Size 467 coarse aggregate gradation: 4.5 to 6.5 percent

b. For AASHTO Size 57 or 67 coarse aggregate gradation: 5.0 to 7.0 percent

2. Class B Concrete

Air Content

MSA (inches) (% by Volume)

1/2 5 - 9 3/4 4 - 8 1 3.5 - 6.5

1-1/2 3 - 6 2 2.5 - 5.5 3 1.5 - 4.5

3. Class C concrete will not require air entrainment unless it will be subject to freeze-thaw cycles. If subject to freeze-thaw cycles, use table in 2.04E2 above to determine air content requirement.

4. Maximum air content for interior slabs subject to abrasion: 3% percent

5. For mix design, determine air content in accordance with ASTM C231 or ASTM

C173.

F. Minimum Cement Content for Class A Concrete

1. For AASHTO M43, Size 467 coarse aggregate gradation: 517 pounds per cubic yard

2. For AASHTO M43, Size 57 coarse aggregate gradation: 536 pounds per cubic yard

3. For AASHTO M43, Size 67 coarse aggregate gradation: 564 pounds per cubic yard

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G. Maximum Water Content for Class A Concrete

1. For AASHTO M43, Size 467 coarse aggregate gradation: 29 gallons per cubic yard

2. For AASHTO M43, Size 57 coarse aggregate gradation: 30 gallons per cubic yard

3. For AASHTO M43, Size 67 coarse aggregate gradation: 32 gallons per cubic yard

4. In water content computation, include volume of admixtures and free moisture in aggregates.

H. Slump

1. Class A and Class B Concrete: One (1) to three (3) inches.

2. Class C Concrete: Two (2) to six (6) inches.

3. Concrete containing high-range, water-reducing admixture (super plasticizer):

Maximum eight (8) inches after super plasticizer is added.

I. Admixtures

1. Use high-range, water-reducing admixture (super plasticizer) in:

a. Concrete which will be pumped.

b. Concrete used in structures required to be watertight.

2. Use accelerator admixture in concrete used for slabs placed at ambient temperatures below 50F. Do not use accelerator admixture for any other work, unless approved by the Engineer.

3. Use retarding admixture during hot weather only when approved by the Engineer.

4. Use other admixtures as specified when required to facilitate placement and finishing.

2.05 CONCRETE MIXING

A. Mix and deliver concrete to the Project in accordance with ASTM C94, Alternative No. 1.

B. When ambient temperature is between 85 and 90F, mixing time plus delivery time shall be not greater than 75 minutes.

C. When ambient temperature is above 90F, mixing time plus delivery time shall be not greater than sixty (60) minutes.

PART 3 - EXECUTION

3.01 PREPARATION

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A. Install vapor barrier under interior slabs on grade. Lap joints minimum six (6) inches and seal watertight with tape.

B. Install forms in accordance with Section 03100: Concrete Formwork.

C. Install joints in accordance with the Drawings.

D. Install reinforcement in accordance with Section 03200: Concrete Reinforcement and the approved Shop Drawings.

E. Set anchor bolts and secure in place to prevent movement during concrete pour.

F. Repair vapor barrier damaged during placement of reinforcement. Repair with vapor barrier material; lap over damaged spots minimum six (6) inches and seal watertight.

G. Apply temporary protective covering to lower two (2) feet of finished wall adjacent to slabs to guard against splattering of walls during pouring of slab.

H. Notify Engineer of readiness to proceed at least twenty-four (24) hours prior to each concrete placement.

I. Do not proceed with concrete placement until Engineer has inspected the pour area.

J. Notify testing lab of requirement for concrete testing services at least twenty-four (24) hours prior to each concrete placement.

K. Verify that forms, joints, embedded items, vapor barrier, reinforcement, and items installed by other trades are in place and properly positioned.

L. Verify that concrete cover over reinforcement will be as shown on the Drawings.

3.02 CONCRETE CONVEYING

A. Place concrete in conformance with the placement schedule approved by Engineer.

B. Place concrete in compliance with practices and recommendations of ACI 304R and as specified herein.

C. Deposit concrete continuously and in layers of thickness such that no concrete will be placed on concrete which has hardened to the point that planes of weakness (cold joints) will result.

D. Deposit concrete as close as possible to its final location to avoid segregation due to rehandling and forcing flow with vibrators.

E. Consolidate concrete during placing operations so that concrete is thoroughly worked

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F. Consolidate placed concrete by mechanical vibrating equipment supplemented by hand-spading, rodding, or tamping. Use equipment and procedures for consolidation of concrete in accordance with ACI 309R.

G. Do not use vibrators to transport concrete inside forms. Insert and withdraw vibrators vertically.

H. Place vibrators to rapidly penetrate placed layer and at least six (6) inches into preceding layer.

I. Do not insert vibrators into lower layers of concrete that have begun to set.

J. At each insertion, limit duration of vibration to time necessary to consolidate concrete and complete embedment of reinforcement and other embedded items without causing segregation of mix.

K. Do not use concrete which becomes non-plastic, or which has been contaminated by foreign materials.

L. The retempering of concrete which has partially hardened (that is, mixing it with additional cement, aggregates, or water) will not be permitted.

M. Do not add extra water to mix after the mixing cycle has been completed.

3.03 COLD WEATHER PLACING

A. Comply with ACI 306R and the following:

1. In cold weather when air temperature falls below 40F, heat the concrete aggregates and water so that the concrete mass, when placed in the forms, has a temperature not lower than 60F and not higher than 80F at point of placement.

2. Heat the aggregates and the water by dry heat or steam, so as to produce a uniform temperature throughout the mass without local overheating. Do not heat water to a temperature of more than 165F.

3. Keep concrete at a temperature not lower than 60F for a period of seven (7) days after placing the concrete, and at a temperature not lower than 40F for a period of four (4) days thereafter.

4. Protect concrete during cold weather by means of a heated enclosure or by insulation.

a. When concrete is protected by the use of an enclosure, keep enclosure sufficiently tight to prevent local cooling due to drafts and heated in such a

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b. When concrete is protected by insulation, use insulation material with a thickness and thermal conductivity properties such as will ensure the maintenance of the required temperatures for the specified period of time throughout the entire mass of concrete.

5. Do not use calcium chloride, salt, or other materials containing antifreeze agents.

3.04 HOT WEATHER PLACING

A. Comply with ACI 305R and the following:

1. Cool ingredients before mixing to maintain concrete temperature at time of placement below 90F. Mixing water may be chilled or chopped ice may be used to control temperature provided water equivalent of ice is calculated to total amount of mixing water. Use of liquid nitrogen to cool concrete is Contractor's option.

2. Cover reinforcing steel with water-soaked burlap so that steel temperature will not exceed the ambient air temperature immediately before embedding in concrete.

3. Fog spray forms, reinforcing steel and subgrade just before concrete is placed.

4. Use water-reducing retarding admixture (Type D) when required by high temperatures, low humidity, or other adverse placing conditions.

3.05 CONCRETE FINISHING

A. Formed Surfaces

1. Rough Form Finish: For formed concrete surfaces not exposed to view in the finished work. Surface texture shall be imparted by form facing material used, with tie holes and defective areas repaired and patched and fins and other projections exceeding ¼” in height rubbed down or chipped off.

2. Smooth Form Finish: For formed concrete surfaces that are to be covered with a coating material applied directly to concrete, or a covering material applied directly to concrete, such as dampproofing.

a. Surface texture shall be obtained with selected form facing material, arranged orderly and symmetrically with a minimum of seams.

b. Repair and patch defective areas with fins or other projections completely removed and smoothed.

3. Smooth Rubbed Finish: For concrete surfaces exposed to view.

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a. Provide smooth rubbed finish to concrete surfaces, which have received smooth form finish treatment, not later than one (1) day after form removal.

b. Moisten concrete surfaces and rub with carborundum brick or other abrasive until a uniform color and texture is produced.

c. Do not apply cement grout other than that created by the rubbing process.

4. Related Unformed Surfaces: For tops of walls, horizontal offsets, and similar unformed surfaces occurring adjacent to formed surfaces.

a. Strike-off smooth and finish with a texture matching adjacent formed surfaces.

b. Continue final surface treatment of formed surfaces uniformly across adjacent unformed surfaces, unless otherwise indicated.

B. Slab Finishes

1. Float Finish: For slab surfaces to receive trowel finish and other finishes as hereinafter specified.

a. After screeding, consolidating, and leveling concrete slabs, do not work surface until ready for floating.

b. Begin floating when surface water has disappeared or when concrete has stiffened sufficiently to permit operation of power-driven floats, or both.

c. Consolidate surface with power-driven floats or by hand-floating if area is small or inaccessible to power units.

d. Check and level surface plane to tolerances in accordance with ASTM

E1155. Cut down high spots and fill low spots.

e. Uniformly slope surfaces to drains.

2. Trowel Finish: For slab surfaces to be exposed to view, slab surfaces to be covered with curing and sealing compound, curing and hardening compound, or other thin film finish coating system and equipment mounting of surfaces.

a. After floating, begin first trowel finish operation using a power-driven trowel. Begin final troweling when surface produces a ringing sound as trowel is moved over surface.

b. Consolidate concrete surface by final hand-troweling operation, free of

West Branch Regional Authority 03300-13 January 2026 trowel marks, uniform in texture and appearance, and with surface leveled to tolerances in accordance with ASTM E1155.

c. Grind smooth surface defects which would reflect through applied floor covering system.

3. Non-Slip Broom Finish: For exterior concrete platforms, building entrance slabs, steps and ramps, and elsewhere as indicated. Immediately after trowel finishing, slightly roughen concrete surface by brooming with fiber bristle broom perpendicular to traffic movement.

3.06 CONCRETE CURING

A. Timing

1. Initial Curing: Start as soon as free water has disappeared from concrete surface after placing and finishing. During initial curing, keep continuously moist for not less than seven (7) days.

2. Final Curing: Begin immediately following initial curing and before concrete has dried. Continue final curing for at least seven (7) days. Avoid rapid drying at the end of the final curing period.

B. Curing Methods

1. Moisture Curing: Use one of the following methods:

a. Cover surface with water.

b. Provide continuous fog spray.

c. Cover concrete surface with specified absorptive cloth. Thoroughly saturate cover with water and keep continuously wet.

2. Moisture Retaining Cover Curing: Cover concrete surface with specified moisture-retaining fabric.

3. Compound Curing: Spray specified compound evenly on surface within two (2) hours after finishing operations are complete. Provide a second coat, to provide sealing and dustproofing, after curing period.

4. Form Curing: Leave forms in place during the curing period.

C. Curing Schedule

1. Formed Surfaces

a. For exposed concrete surfaces such as tops of walls, provide moisture curing during the initial curing period and then either moisture curing or moisture retaining cover curing during the final curing period.

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b. When temperature is above 80F, provide continuous fog spray against all exposed form surfaces.

c. When forms are stripped during the initial curing period, continue curing with the moisture curing method to the end of the seven-day (7) period.

d. When forms are stripped during the final curing period, continue curing with either the moisture curing or moisture retaining cover curing method to the end of the seven-day (7) period.

2. Unformed Surfaces

a. All surfaces: Compound curing.

b. Provide curing as specified above on all exposed surfaces, including edge of slabs.

3.07 CONCRETE REPAIR

A. Formed Surfaces

1. Repair immediately after removal of forms.

2. Use a non-shrink grout which matches the color of the surrounding material.

3. For honeycomb and voids over 1/4-inch in any dimension:

a. Cut out down to solid concrete.

b. Make edges of cut perpendicular to surface.

c. Where reinforcing steel is involved, cut or chip around bars to provide 3/4-inch clearance all around bars.

d. Clean hole and thoroughly wet all surfaces with water.

e. Fill hole with non-shrink grout in accordance with manufacturer's instructions.

f. Cure patch in accordance with the non-shrink grout manufacturer's instructions.

4. For form tie holes:

a. Clean hole with compressed air.

b. Thoroughly wet all surfaces of hole with water.

c. Pack non-shrink grout into hole in accordance with manufacturer's

d. Cure non-shrink grout in accordance with manufacturer's instructions.

B. Unformed Surfaces

1. Test surface for flatness and levelness in accordance with ASTM E1155.

2. High Spots: Correct by grinding after concrete has cured at least fourteen (14)

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3. For patching, use a non-shrink grout which matches the color of the surrounding material.

4. For low spots:

a. Cut out low area to a minimum depth of one (1) inch below the surface surrounding the low spot.

b. Make cuts perpendicular to surface.

c. Clean area to be patched and thoroughly wet all surfaces with water.

Remove any standing water.

d. Fill cut out area with non-shrink grout in accordance with manufacturer's instructions. Strike off even with surrounding area.

e. Cure patched area in accordance with manufacturer's instructions.

f. Proprietary leveling compounds, designed to feather-edge into the substrate, may be used when approved by the Engineer.

5. For voids over 1/4-inch in any dimension and cracks in excess of 0.02 inches wide:

a. Cut out voids to solid concrete. Make cuts perpendicular to surface.

Where reinforcement is involved, cut out to provide at least 3/4-inch clearance all around the bars.

b. Cut minimum 1/4-inch wide by 1/2-inch deep continuous groove along top of cracks.

c. Clean area to be patched and thoroughly wet all surfaces with water.

Remove any standing water.

d. Fill area to be patched with non-shrink grout in accordance with manufacturer's instructions.

e. Cure patch in accordance with manufacturer's instructions.

C. Structural Repairs: Obtain approval of the Engineer for method used in any repairs which may affect structural integrity.

3.08 MISCELLANEOUS CONCRETE ITEMS

A. Filling In: Fill-in holes and openings left in concrete structures for passage of work by other trades, unless otherwise shown or directed, after work of other trades is in place.

Mix, place, and cure concrete to blend with in-place construction. Provide other miscellaneous concrete filling shown or required to complete the work.

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B. Curbs: Provide a monolithic finish to interior curbs by stripping the forms while the concrete is still green, and steel-troweling the surfaces to a hard, dense finish with the corners, intersections, and terminations slightly rounded.

C. Equipment Bases and Foundations: Provide machine and equipment bases and foundations as shown on the Drawings. Set anchor bolts for machines and equipment with a template at the correct elevations, complying with certified diagrams or templates of the manufacturer furnishing the machines and equipment. Cast all anchors into the concrete.

Drilling and use of expansion or adhesive anchors will not be permitted unless shown otherwise on the Drawings or approved by the Engineer.

D. Bonding: Before depositing new concrete on or against concrete that has set thoroughly, roughen and clean existing surfaces of laitance, foreign matter, and loose particles.

Thoroughly clean reinforcement of concrete, rust, and other foreign matter with wire brush or other approved means. Slush existing surfaces with neat cement coat. Place new concrete before neat cement has attained initial set. Where a thin layer of concrete (four

(4) inches or less) is placed on or against hardened concrete, use a bonding adhesive in place of the neat cement coat. Apply bonding adhesive in accordance with manufacturer's

3.09 SCHEDULE

A. Class A Concrete: All reinforced piers, walls, slabs, columns, beams, and footings and all other reinforced concrete unless shown otherwise on the Drawings or specified in these Specifications.

B. Class B Concrete: All concrete which is shown on the Drawings or specified in the

Specifications as Class B.

C. Class C Concrete: Fill concrete and all other non-reinforced concrete such as that used in thrust blocks, unless shown otherwise on the Drawings or specified in these Specifications.