Table of Contents
| Section | Title | Page |
| Purpose | 2 | |
| Scope | 2 | |
| Related Documents | 2 | |
| Materials and Products | 3 | |
| Concrete Mixes | 5 | |
| Equipment and Facilities | 7 | |
| Form Work | 8 | |
| Embedded Items | 8 | |
| Concrete Construction | 9 | |
| Testing and Inspection | 12 | |
| Change Log | 14 |
1. Purpose
1.1 This specification defines the minimum requirements for materials, testing, installation, and inspection of concrete work.
2. scope
2.1 The contractor shall furnish all supervision, labor, materials, tools, equipment, and services necessary to produce, deliver, and place ready-mixed concrete at the job site. The term “ready-mixed concrete” (as used herein) shall be understood to be applicable to concrete produced by the central-mixed, shrink-mixed, or truck-mixed methods.
3. RELATED DOCUMENTS
3.1 Air Products Engineering Document
4WCE-600001 General Scope of Work for Construction Contracts
309707D LOX Compatible Joint Details for Concrete Work
3.2 American Concrete Institute (ACI)
117 Standard Specifications for Tolerances for Concrete Construction and Materials
211.1 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete
301 Specifications for Structural Concrete
304R Guide for Measuring, Mixing, Transporting, and Placing Concrete
305R Guide to Hot Weather Concreting
306R Guide to Cold Weather Concreting
308.1 Specification for Curing Concrete
309R Guide for Consolidation of Concrete
318 Building Code Requirements for Structural Concrete and Commentary
347 Guide to Formwork for Concrete
3.3 American National Standards Institute (ANSI)
A10.9 Concrete and Masonry Work Safety Requirements
3.4 American Society of Civil Engineers (ASCE)
37-02 Design Loads on Structures During Construction
3.5 American Society for Testing and Materials (ASTM)
C 31 Practice for Making and Curing Concrete Test Specimens in the Field
C 33 Specification for Concrete Aggregates
C 39 Test Method for Compressive Strength of Cylindrical Concrete Specimens
C 94 Specification for Ready-Mixed Concrete
C 143 Test Method for Slump of Hydraulic Cement Concrete
C 150 Specification for Portland Cement
C 172 Practice for Sampling Freshly Mixed Concrete
C 173 Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method
C 231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C 260 Specification for Air-Entrainment Admixtures for Concrete
C 309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C 311 Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in Portland Cement Concrete
C 494 Specification for Chemical Admixtures for Concrete
C 618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Concrete
D1667 Standard Specification for Flexible Cellular Materials—Poly (Vinyl Chloride) Foam (Closed-Cell)
3.4 National Ready-Mixed Concrete Association (NRMCA)
Plant Certification Checklist – Section 3 Certification of Ready-Mixed Concrete Production Facilities
3.5 All specifications or codes referenced shall be the latest editions.
4. MATERIALS AND PRODUCTS
4.1 General
4.1.1 The contractor shall supply materials (including cement, aggregates, water, and admixtures) that comply with ASTM C 94 and as specified herein.
4.1.2 Concrete materials, as applicable, shall be properly identified after testing at place of manufacture.
4.2 Cement
4.2.1 Portland Cement concrete shall conform to the requirements of ASTM C 150. Type I shall be used unless otherwise specified on the contract drawings.
4.2.2 Only one brand and source of cement shall be used for the entire project, unless a change is specifically permitted by the Air Products representative.
4.3 Aggregates
4.3.1 Concrete aggregates shall conform to ASTM C33. Maximum size shall not exceed 1/5 of the narrowest form dimension, 3/4 of the minimum clear spacing between reinforcing bars, and in no case be larger than 38 mm (1 1/2 in), unless otherwise specified on the contract drawings.
4.4 Water
4.4.1 Water used in mixing concrete shall conform to the requirements of Section 3.4 of ACI 318.
4.4.2 Water must be clean and free from injurious oils, acids, alkalies, organic materials, or other deleterious substances.
4.5 Admixtures
4.5.1 Admixtures shall conform to the requirements of Section 3.6 of ACI 318.
4.5.2 Concrete admixtures shall be used in accordance with the manufacturer’s printed instructions.
4.5.3 Water-reducing admixtures (Type A, D, or F) may be added to concrete mixes, except that the Type D admixture for cold weather concrete shall be used only if approved by Air Products.
4.5.4 All admixtures shall be added at the batch plant unless otherwise specified.
4.5.5 Admixtures may be selected from the following table without prior approval:
| Admixture | Products | Manufacturers | |
| Air-entraining
(ASTM C 260) |
MB-VR Standard | BASF
The Chemical Company |
|
| DARAVAIR | Grace Concrete Products
|
||
| Water-reducing
(ASTM C 494 – Type A) |
POZZOLITH 200N | BASF
The Chemical Company |
|
| WRDA with HYCOL | Grace Concrete Products
|
||
| Water-reducing Retarder
(ASTM C 494 – Type D) |
POZZOLITH 100-XR | BASF
The Chemical Company |
|
| DARATARD-17 | Grace Concrete Products
|
||
| High Range Water Reducer | GLENIUM 7107 | BASF
The Chemical Company |
|
| (ASTM C 494 – Type F) | |||
| ADVA 140M | Grace Concrete Products
|
4.5.6 Fly ash (Class C or Class F) shall be in accordance with ASTM C-618 and shall only be used with the prior approval of Air Products. The amount of fly ash that may be substituted for cement shall be less than 20% by weight of the total cement intended for the designated mix and shall not exceed 100 lbs per cubic yard of concrete. Class F is recommended where sulfate resistance is a concern. Concrete mixes with Class C typically will develop higher early strengths than Class F mixes.
4.5.6.1 Use only one source of fly ash. Each shipment shall have test reports (at a frequency of not less than one test for each 50 tons of fly ash delivered) certifying compliance with ASTM C 311.
4.5.7 Use of blast furnace slag is prohibited.
4.5.8 Use of calcium chlorides is prohibited.
4.6 Curing Compounds
4.6.1 All compounds shall conform to the requirements of ASTM C 309 Type 1. Curing compounds shall be used in accordance with the manufacturer’s printed specifications.
4.6.2 The contractor is not permitted to use compounds on surfaces that will receive additional concrete.
4.6.3 Curing compounds may be selected from the following list or an approved equal:
R. Meadows
1600-White
L&M Construction Chemicals Inc.
L&M Cure
4.6.3.1 The use of curing compounds other than those listed is strictly prohibited without the prior written permission of the Air Products representative.
4.7 Water Stops
4.7.1 Water stops shall be either a PVC dumbbell type without center bulb or pre-formed plastic adhesive nonexpansive water stops. PVC dumbbell type will typically be 6 inches wide and the pre-formed plastic adhesive type will typically be 3/4 inch by 1 1/4 inch in cross-section. Any deviations from this size shall be as indicated on the contract drawings.
4.8 Vapor Barrier
4.8.1 Vapor barriers placed under concrete slabs shall be of 4 mil thick polyethylene plastic sheeting.
4.9 Expansion Joint Filler and Sealer
4.9.1 Expansion joint filler shall be continuous, 1/2 inch thick, organic (closed cell) nonextruding semi-rigid PVC foam that satisfies the requirements of ASTM D1667 Grade DE-45. Joint sealer shall be two component polysulfied rubber sealant. Color shall be medium gray. All products shall be applied in accordance with the manufacturer’s recommendations. Materials mentioned as follows are approved for use:
Expansion Joint Filler
– Rodofoam Grade #327
Joint Sealer
– W. R. Meadows DecoSeal 150 (vertical and non-traffic bearing horizontal joints)
– W. R. Meadows DecoSeal One Step (typical horizontal joints exposed to pedestrian/vehicular traffic)
Primer
– W. R. Meadows P/G Primer
4.10 Water Seal
4.10.1 Water seal shall be a clear water-based acrylic concrete sealer.
5. CONCRETE MIXES
5.1 General
5.1.1 Ready-mixed concrete shall conform to the requirements of ASTM C 94.
5.1.2 Concrete mixes shall be proportioned in accordance with ACI 211.1, and ACI 301.
5.1.3 The contractor shall employ an independent testing laboratory to establish the proportions of the design mixes and provide preliminary cylinder testing.
5.1.4 The cost of the design mix and preliminary cylinder tests shall be paid by the contractor.
5.2 Mix Design
5.2.1 Strength
5.2.1.1 All concrete shall have a minimum compressive strength of 4000 psi at 28 days, unless otherwise specified on the contract drawings.
5.2.2 Water-Cement Ratio
5.2.2.1 The maximum permissible water-cement ratio for concrete shall conform to the following table, unless strength data or trial mixtures are available. The amount of water and the proportion of mortar to coarse aggregate for each mix shall (at all times) be the least which will produce uniformly dense concrete, free from aggregate pockets or honeycombs.
| Concrete Strength
(psi) |
Water-Cement Ratio
(max) |
Water-Cement Ratio
(max) |
| (non air-entrained) | (air-entrained) | |
| 2000 | 0.76 | 0.62 |
| 3000 | 0.58 | 0.46 |
| 4000 | 0.44 | 0.35 |
These values are not applicable when concrete contains admixtures other than those used exclusively for entraining air.
5.2.3 Air Entrainment
5.2.3.1 Air entrainment shall be in accordance with ASTM C 260.
5.2.3.2 All concrete shall contain 6% air entrainment with an allowable tolerance of 1%, unless otherwise specified on the contract drawings.
5.2.4 Workability
5.2.4.1 The proportions of aggregate to cement for any concrete mix shall produce a mixture that will work readily into the corners and angles of the forms and around reinforcement with the method of placing employed, but without permitting the materials to segregate or excess free water to collect on the surface. The proportion by volume of coarse aggregate to cement shall be as specified in ACI 211.1.
5.2.5 Slump
5.2.5.1 Concrete slumps shall be as indicated in this section. A tolerance of up to 1 inch above the maximum indicated will be allowed for one batch in any five consecutive batches tested.
5.2.5.2 Concrete shall be proportioned to comply with the slump requirements as follows:
Slump Requirements (All Dimensions in Inches)
|
Concrete Use |
Maximum
Aggregate Size |
Working Slump |
Maximum
Slump (Rejection) |
|
| Foundations and Grade Beams | 1 1/2 | 4 | 5 | |
| Water Retaining Structures | 3/4 | 3 | 4 | |
| Slabs/Walls less than 8 in | 3/4 | 4 | 5 | |
| Tremie | 3/4 | 4 | 6 | |
| Backfill | 2 | 5 | 6 | |
| All Other Normal Weight Concrete | 1 1/2 | 4 | 5 |
5.2.5.3 The maximum slump of the concrete may exceed the values listed in this table if the mix has included a high range water reducing admixture which is necessary for the type of placement. This type of deviation must be approved in writing by the Air Products design engineer.
5.2.5.4 Concrete may be supplied with a slump less than the working slump listed above if it can be properly placed and consolidated.
5.2.6 Submittals
5.2.6.1 The contractor shall submit the proposed concrete mix to the Air Products representative for approval. All mix designs must be submitted at least 15 days in advance of the concrete operation to which the mix applies. A proposed mix design must be submitted for each concrete compressive strength required by contract drawings and specifications.
5.2.6.2 All of the following information shall accompany each mix design:
Type of structure(s) to which mix applies, that is. , floors, foundations, and walls.
Sources of aggregate and test data certifying the requirements of ASTM C 33.
Complete gradation and fineness modulus of both fine and coarse aggregates.
Specific gravity of both fine and coarse aggregates and cement.
Dry, rodded unit weight of both fine and coarse aggregate.
Quantities of all components of the mix, including air entrainment agents, superplasticizer, and other admixtures, if used.
Where admixtures are used, the manufacturer’s information shall accompany the mix design.
Results of a 7-day and 28-day cylinder test using the proposed mix. (All tests shall be conducted in accordance with paragraph 10 and any subsections thereof.)
Plant standard deviation, if available.
Type of cement, such as, Type I, II, or III.
5.2.6.3 No substitution of materials of an approved mix design shall be made without the prior written approval of the Air Products representative. All of the above must be submitted to obtain approval.
5.2.6.4 Air Products approval of the concrete design mix does not relieve the contractor of the responsibility to furnish materials and construction in full conformance with the drawings and specifications.
5.2.6.5 If, during the progress of the work, it is desired to use materials or proportions other than those originally approved or if the materials from the sources originally approved change in characteristics, the contractor shall submit for approval evidence that the new combinations of materials will produce concrete meeting the requirements of this specification and will not bring about objectionable changes in color, appearance, or structural strength.
6. EQUIPMENT AND FACILITIES
6.1 Batch Plant Equipment
6.1.1 The contractor shall employ a concrete batch plant facility which complies in all respects to the requirements of ASTM C 94, and to Plant Certification Checklist – Section 3, “Certification of Ready-Mixed Concrete Production Facilities” of the NRMCA.
6.2 Storage Facilities
6.2.1 The storage of cement, aggregates, and additives shall be accomplished in a manner to prevent deterioration and contamination with foreign matter. Each size of aggregate shall be stored separately in a manner to ensure segregation.
6.2.2 Cement that has become caked, partially set, or otherwise deteriorated and any other material that has become contaminated shall be rejected for use. Cement storage shall be weather-tight. All additional requirements of Section 2.3 of ACI 304R shall be met.
6.3 Trucks
6.3.1 Truck mixing and delivery shall conform to the applicable requirements of ASTM C 94.
6.4 Heating Equipment
6.4.1 Adequate equipment shall be provided at the batch plant for heating concrete materials and protecting the concrete in transit during freezing or near freezing weather. The heating equipment shall have sufficient capacity so that the concrete delivered meets the temperature requirements of this specification.
7. FORM WORK
7.1 General
7.1.1 Forms for concrete shall conform exactly to the shape, lines, and dimensions as shown on the contract drawings and shall be built of any commonly accepted material, unless otherwise specified herein.
7.1.2 Design and Installation
7.1.2.1 Form work shall be designed in accordance with ACI 347 and ANSI A10.9. Contractors shall submit formwork calculations and drawings stamped by a registered engineer to Air Products for review. Design loads shall be applied in accordance with ASCE 37-02.
7.1.2.2 Forms in contact with exposed concrete surfaces shall be built of materials having a smooth surface.
7.1.2.3 The inside surface of forms, except for wood or masonry forms, shall be coated with commercial formulation form-coating compounds with a maximum Volatile Organic Compounds (VOC) of 350 mg/L that will not bond with, stain, or adversely affect concrete surfaces and will not impair subsequent treatments of concrete surfaces.
7.1.2.4 Wood and masonry forms shall be, except in freezing weather, thoroughly moistened with water.
7.1.2.5 Cleaned form lumber may be reused if approved by the Air Products representative.
7.1.3 Tolerances
7.1.3.1 All form work shall conform to the tolerance requirements of ACI 117, unless otherwise specified on the contract drawings.
7.1.4 Form Ties
7.1.4.1 Form accessories shall be factory fabricated, adjustable-length, removable or snap-off form ties that are designed to prevent form deflection and prevent spalling concrete upon removal. Types of form ties shall be approved by the Air Products representative. Wire ties will not be permitted in exposed surfaces.
-
EMBEDDED ITEMS
8.1 All anchors, inserts, bolts, sleeves, embedded piping, embedded conduit, and other embedded items shall be placed (secured to prevent movement) and checked before, during, and after the placing of concrete. The correction of all errors in size and location of embedded items shall be performed at the contractor’s expense regardless of the time at which discrepancies may be revealed.
8.2 The contractor shall install water stops of the type, size, and at the locations shown on the drawings. The contractor shall splice the water stop in strict accordance with the manufacturer’s instructions.
8.3 When construction joints are shown on the drawings as being sealed with water stops, additional construction joints requested by the contractor shall also be sealed with water stops.
8.4 Aluminum shall not be used as embedded items under any circumstances.
9. CONCRETE CONSTRUCTION
9.1 General
9.1.1 The measuring, mixing, transporting, and placing of concrete shall be in accordance with the requirements of ACI 304R.
9.2 Mixing and Delivery of Concrete
9.2.1 Concrete shall be conveyed from batch plant to point of truck discharge by truck mixers.
9.2.2 Each batch of concrete delivered to the job shall be accompanied by a delivery ticket. The delivery ticket shall contain all information itemized in Section 14 of ASTM C 94.
9.2.3 Delivery tickets from the concrete supplier shall indicate the number of sacks of cement per cubic yard furnished and the time which water was first added to the mixture.
9.2.4 Delivery tickets shall have space for the following information to be filled in by others:
Ambient temperature at site.
Temperature of concrete at time of truck discharge.
9.2.5 Concrete shall be delivered on the time schedule that will allow placement of concrete within a period of 90 minutes after the first addition of water. During “hot weather” conditions, this time limit shall be 60 minutes. Specific approval by the Air Products representative is required for placement of concrete outside these time limits.
9.2.6 The contractor shall be fully responsible for the quality of the concrete from the batch plant. Responsibility for the condition of the concrete shall be in accordance with ASTM C 94.
9.2.7 Disposal of rejected and waste concrete shall be the responsibility of the contractor and shall only be disposed of onsite with the prior approval of the Air Products representative.
9.2.8 The addition of water over and above the approved mix with water quantity is prohibited.
9.3 Placement of Concrete
9.3.1 General
9.3.1.1 The contractor shall ensure cleanliness of all equipment used for mixing and transporting concrete and shall remove all debris, hardened concrete, water, ice, mud, or other inappropriate materials from the areas to be occupied by placement of new concrete.
9.3.1.2 The contractor shall properly drain all water from excavations in a manner approved by the Air Products representative.
9.3.1.3 The contractor shall place all concrete monolithically, unless otherwise specified or shown upon the drawings.
9.3.1.4 Before placing new concrete on previously placed or old concrete, the surfaces shall be thoroughly cleaned with air or water to remove all oil scum, laitance, or other inappropriate materials. Surfaces shall then be wetted down or shall receive an application of a bonding agent as indicated in the contract drawings.
9.3.1.5 Successive lifts shall be placed in a manner that will prevent segregation. No free fall shall be greater than 1.5 m (5 ft); otherwise, tremies shall be used.
9.3.1.6 All concrete placed shall be consolidated in accordance with ACI 309R.
9.3.1.7 When a vapor barrier is not used, the subgrade shall be prepared by moistening with water. When a vapor barrier is used, care must be taken to provide adequate laps and prevent puncturing of the vapor barrier.
9.3.1.8 Expansion joint filler strips shall be used where slabs abut vertical surfaces and at other locations shown on the contract drawings. Materials specified in Section 4 are for standard joints. LOX compatible joints, where denoted on the contract drawings, shall be in accordance with 309707D.
9.3.1.9 Contraction, expansion, and construction joints shall be installed by the contractor in accordance with the contract drawings. Additional construction joints not shown on the contract drawings shall have the written approval of the Air Products representative. The contractor shall apply water seal to the exposed edges of specified joints.
9.3.1.10 The contractor shall exercise extreme caution to minimize the disturbance of reinforcing bars, reinforcing mats, sleeves, or other embedded items during the placement of concrete.
9.3.2 Hot Weather Concreting
9.3.2.1 The current edition of ACI 305R shall be part of this specification.
9.3.2.2 The hot weather provisions of ACI 305R shall be initiated when any of the following conditions are applicable:
Air temperature is 32.2 °C (90°F) or higher regardless of humidity.
Air temperature is 26.7°C (80°) to 31.6°C (89°F) and relative humidity is 60%, or less.
Air temperature is 21.1°C (70°) to 26.1°C (79°F) and relative humidity is 40%, or less.
9.3.3 Cold Weather Concreting
9.3.3.1 The current edition of ACI 306R shall be a part of this specification.
9.3.3.2 Cold weather provisions of ACI 306R shall be initiated when the following condition is applicable:
Period when the average daily temperature of air is below 4.4°C (40°F) for more than three successive days. When temperatures above 10°C (50°F) occur during more than half of any 24‑hour period, the period should no longer be regarded as cold weather.
9.4 Finishes
9.4.1 Unless specified otherwise on the contract drawings or in this specification, concrete surfaces shall be screeded thoroughly, compacted, and finished with a wood or cork float at the elevation designated on the contract drawings.
9.4.2 Exterior walkways and door stoops shall receive a broom finish in a pattern perpendicular to the traffic flow.
9.4.3 The contractor shall rub only those exposed surfaces that have cracked, broken, or show “honeycombing” or as directed by the Air Products representative. Before the concrete has thoroughly hardened, wet down the surface to be rubbed with water and rub with carborundum to a smooth, uniform finish. During the rubbing, use a thin grout consisting of Portland Cement concrete and fine, light-colored sand mixed to the consistency of paint. A few hours after rubbing, the film of grout shall be removed by washing with clean water.
9.4.4 Tolerances shall be in accordance with ACI 117, unless otherwise specified on the contract drawings.
9.5 Curing of Concrete
9.5.1 The curing of concrete shall be in accordance with ACI 308.1.
9.5.2 The contractor shall protect all concrete as required to maintain the surface temperature above 10°C (50°F) for the first five consecutive days after placement.
9.5.3 Curing shall be accomplished by preventing loss of moisture, rapid temperature change, and mechanical injury or injury from rain or flowing water for a period of five days. Curing shall commence immediately after the finishing operations have been completed and the concrete has set sufficiently to prevent marring the surface.
9.5.4 Curing of formed undersurfaces of beams, floor slabs, and other similar undersurfaces shall be accomplished by moist curing with forms in place for the full curing period or, if forms are removed before the end of the curing period, by other means as approved in writing by the Air Products representative.
9.5.5 Unformed surfaces shall be covered with burlap, cotton, or other fabric mats, as approved by the Air Products representative. Alternatively, the contractor may use curing compounds as set forth in paragraph 4.6.
9.5.6 Burlap covers shall consist of two or more layers of burlap having a combined weight of 14 ounces or more per square yard in a dry condition. Burlap shall be new or shall have been used only for curing concrete. Cotton mats and burlap strips shall have a length, after shrinkage, at least 0.3 m (1 ft) greater than necessary to cover the entire width and edges of the surface to be covered. The mats shall overlay each other at least 150 mm (6 in). The mats shall be thoroughly wetted before placing and shall be kept continuously and in intimate contact with the surface being cured for the duration of the required curing period.
9.5.7 Failure to provide sufficient cover material of the type selected, failure to maintain saturation in the moist-curing method, lack of adequate water for both curing and other requirements, or other failures to exercise reasonable and proper care consistent with good engineering practice shall be cause for immediate suspension of concreting operations.
9.5.8 Wetted covers shall not be used when concrete is placed under the provisions of ACI 306R. Polyethylene covers shall be used.
9.6 Removal of Forms
9.6.1 The contractor shall not remove forms without the written approval of the Air Products representative. The following tables shall be used to determine the minimum curing time required before the removal of forms:
|
Structural Classification |
Minimum
Concrete Strength (psi) |
| 1. Concrete not subject to appreciable bending or direct stress, nor relying upon forms for vertical support, nor liable to injury from other construction activity. | 500 |
| 2. Concrete subject to appreciable bending and/or direct stress and relying on forms for vertical support: | |
| a Subject to dead load only. | 750 |
| b. Subject to dead load and live load. | 1500 |
| 3. Concrete subject to high bending stress and wholly relying on forms for vertical support. | 2000 |
Probable Strength Gain
| Age | Cements | |
| (moist cured @ 70°F) | Type I and II | Type III |
| 12 Hours | — | 500 |
| 18 Hours | — | 750 |
| 36 Hours | 500 | 1500 |
| 60 Hours | 750 | 2000 |
| 3 1/2 Days | 1500 | — |
| 5 1/2 Days | 2000 | — |
9.6.2 After the removal of forms, the contractor shall patch all voids, pockets, tie holes, cracks, or other surface imperfections with cement mortar in a neat and thorough manner. Where necessary, the contractor shall chip away defective areas to a depth not less than 25 mm (1 in) with the edges perpendicular to the surface. The surface to be patched and an area at least 152 mm (6 in) wide entirely surrounding it shall be kept wet for at least four hours before patching and shall be kept moist for at least five days after patching.
9.6.3 The contractor shall make the patch of the same material proportions used for the concrete, except that the coarse aggregate shall be omitted. The mixing water shall be as little as is consistent with the requirements of handling and placing.
10. Testing and Inspection
10.1 General
10.1.1 In accordance with the requirements of Air Products specification 4WCE-600001, the contractor will select and pay for the services of an independent testing laboratory to perform inspection and tests of materials and construction.
10.1.2 The approval of the laboratory by Air Products in no way relieves the contractor of the responsibility to furnish materials and workmanship in full conformance with the drawings and specifications.
10.1.3 The contractor shall cooperate with the testing laboratory and the Air Products Representative:
Make available, without cost, samples of all materials to be tested.
Furnish labor and sheltered working space as may be necessary to obtain samples at the project site.
Identify material sources and instruct the suppliers to allow tests or inspections by the laboratory.
Notify the testing laboratory sufficiently in advance of operation to allow the testing laboratory time for completion of initial tests and assignment of inspection personnel.
10.2 Samples
10.2.1 The method of sampling fresh concrete and the method of making, curing, and testing specimens shall be in accordance with ASTM C 31, ASTM C 39, and ASTM C 172. ASTM C 31 requires that the cylinder be stored with the pour for 24 hours, then prepared for shipment to the laboratory for standard curing until tested.
10.3 Test
10.3.1 Slump
10.3.1.1 The slump shall be determined in accordance with ASTM C 143.
10.3.1.2 One test shall be performed for each truck delivery of concrete. When visual inspection by the inspector indicates that the consistency or workability of the concrete has changed since the last test, additional slump tests shall be made before pouring is completed.
10.3.2 Air Content
10.3.2.1 Tests for air content shall be in accordance with ASTM C 173 or ASTM C 231. One air entrainment test shall be performed for each truck delivery.
10.3.3 Concrete Cylinders
10.3.3.1 Four cylinders for each class of concrete placed shall be taken for each day’s pour of 76.5 cubic meters (100 cubic yards) (or fraction thereof).
10.3.3.2 The contractor shall provide additional test cylinders upon the request of the Air Products representative, if job requirements indicate additional samples are necessary.
10.3.3.3 Two cylinders shall be tested and reported at seven days and two at 28 days. The minimum compressive strength at 28 days shall be as shown in the following table:
Compressive Strength Test Results
| Specified
Minimum Strength at 28 Days (psi) |
Average for
Any Set of Two Cylinders (psi) |
Any One Cylinder (psi) |
| 3000 | 3450 | 3000 |
| 3500 | 4020 | 3500 |
| 4000 | 4580 | 4000 |
10.3.3.4 Certified reports of such tests shall be forwarded immediately to the Air Products representative by the testing laboratory.
10.3.3.5 Concrete made with Type III cement shall have a seven day compressive strength equal to 85% of the specified minimum 28 day compressive strength of concrete made with Type I cement.
10.3.3.6 If the 28-day test fails to meet the minimum specified compressive strength, any follow-up tests such as core borings and additional strength tests, and/or the removal and replacement of concrete will be to the account of the contractor without cost to Air Products. Removal and replacement shall be under the direction of the Air Products representative. Final determination to accept or reject a foundation will be based on the test data and will be solely the decision of the Air Products representative.
10.4 Reports
10.4.1 The laboratory shall submit written reports of each test and inspection made to the Air Products representative and the contractor.
10.5 Job Inspection
10.5.1 A representative of the testing laboratory on the project shall immediately report to the Air Products representative any substandard concreting operation observed while at the job site.