B01 Attachment J01b TP-02 Concrete APRIL 2021.pdf

TECHNICAL PROVISIONS - SECTION 02 - Page 1 of 4

April 2021

TECHNICAL PROVISIONS

SECTION 02 - CONCRETE

TP-201 SCOPE

Furnish all labor, materials, equipment, and incidentals as required, and perform all operations in connection with the placement of concrete in accordance with the applicable drawings and these specifications.

TP-202 MATERIAL:

A. Cement: Portland cement shall conform to ASTM C150 Cement, Portland Type I, Type

IA, Type II, Type IIA, Type III, or Type IIIA.

B. Aggregate: Aggregate shall be composed of clean, hard, durable, uncoated grains and crushed stone, free from detrimental amounts of clay, dust, soft or flaky particles, loam, shale, schist, slate, alkali, disintergrated stone, organic matter or other deleterious matter.

C. Water: All water used for concrete shall be of potable quality.

TP-203 CONCRETE REQUIREMENTS

Property Minimum Maximum

Cement Factor (sacks per cu. Yd.) 6.0 ---

Water-Cement Ratio (gal. Per sack) --- 6.0

Entrained Air (percent) 2.0 6.0

Slump (inches) 1.0 4.0

Compressive Strength

7 day (psi) 1,800

28 day (psi) 3,000

Concrete shall be uniformly plastic, cohesive and workable, i.e., can be placed without honeycomb and without voids in the surface. Workability shall be obtained without producing a separation of ingredients such that free water appears on the surface. In general, minimum amount of water required to produce a workable mixture shall be used.

TECHNICAL PROVISIONS - SECTION 02 - Page 2 of 4

TP-204 FREEZING WEATHER:

No concrete work shall be done if the air temperature is below 40 degrees 0F, except with the approval of the Owner or Owner’s Representative. If approval is given to work, the water and aggregate shall be heated to at least 80 degrees 0F, before mixing.

In all cases where the air temperature is predicted to be below 40 degrees 0F, the concrete shall be insulated for at least 72 hours by straw, blankets or other approved methods. No concrete shall be poured against frozen ground.

The use of salt or other compounds to prevent concrete from freezing shall not be permitted. Any work that has been injured by freezing shall be removed and replaced at the Contractor’s expense.

TP-205 CURING:

Fresh concrete shall be adequately protected from heavy rains and mechanical injury. Concrete surfaces shall be kept moist by spraying with liquid membrane coating. Foundations and thrust blocks may be cured by covering with water saturated soil or backfill. All concrete shall be cured at least three days prior to stripping forms or structural loading.

TP-206 TRANSIT MIXED CONCRETE:

Ready-mixed concrete from a central batching plant and mixed in transit will be permitted with the Owner or Owner’s Representative’s approval. A plant batch certification sheet shall be provided by the concrete supplier listing the batch components for approval by the Owner or

Representative.

TP-207 FIELD TESTING:

Four cylinders shall be taken for each 50 cubic yards of concrete placed or portion thereof. If the

Owner or his/her representative suspects, by visual inspection, slump, or other tests, that any other concrete appears substandard, additional test cylinders shall be required. The Contractor shall provide cylinder molds at the construction site and shall have the cylinders tested by an approved laboratory, with the Contractor bearing all costs. If any test cylinder falls below 3000 psi at 28 days, this shall be sufficient cause to reject that portion of concrete. The Contractor shall remove and replace defective concrete with acceptable material at his own expense. The test cylinders shall comply with ASTM C31 for making and curing test specimens in the field. Additional information concerning testing is found in the SPECIAL PROVSIONS.

In addition, the contractor shall perform one slump test and one air entrainment test for each concrete truck.

Field testing will not be required for non-structural concrete placement such as pre-cast manhole

TECHNICAL PROVISIONS - SECTION 02 - Page 3 of 4 bases, concrete collars, yard hydrant concrete pads, fence post concrete anchors, monitoring well concrete pad, control panel concrete pad, cleanout collars, manhole collars, and drop manhole concrete encasements.

TP-208 PLACING CONCRETE:

Before placing concrete, the Contractor shall give 72-hour advance notice to permit proper inspection of forms and reinforcement by the Owner or Representative.

After completion of the mixing, the concrete shall be rapidly conveyed to and deposited in the forms. Consolidate the concrete, immediately after placing, by mechanical vibrating equipment, supplemented by hand-spading, roding, or tamping. Use equipment and procedures for consolidation of concrete in accordance with ACI recommended practices.

The concrete shall be placed in such a manner as to prevent excessive crawling and segregation of the aggregate. No concrete shall be used that has partially set before final placing, nor shall retempering of the concrete be permitted. All concrete shall be placed in the forms no more than

90 minutes after mixing.

TP-209 FORMS:

The Contractor shall provide forms that will produce correctly aligned concrete. The centering of the forms shall be true and rigid and thoroughly braced both horizontally and diagonally. Forms shall be sufficiently strong to carry the dead weight of the concrete as a liquid without deflection, and tight enough to prevent leakage of mortar. The inside of forms shall be coated with an approved oil or thoroughly wetted. The Owner or Representative shall be notified prior to removal of form work.

The final concrete structure shall be inspected for alignment, elevation, and concrete quality. Final concrete structure alignment and elevation shall be checked by use of land surveying instruments.

Should the concrete structure alignment, elevation, and/or quality test results be determined unsatisfactory by the Owner or Owner’s Representative, the entire structure or parts of the structure will be rejected. All further alignment or elevation corrections, or any concrete removal and/or replacement, shall be at the Contractor’s expense.

Honeycombed and void areas in the concrete shall be removed and patched to produce a sound concrete product by a method selected by the Contractor and approved by the Owner or Owner’s

Representative.

TP-210 MORTAR:

Mortar shall be made of one-part masonry cement, three parts sand, and only a sufficient amount of water to make a workable plastic mix. Retempered mortar shall not be used.

TECHNICAL PROVISIONS - SECTION 02 - Page 4 of 4

TP-211 GROUT:

Grout shall be made of one part Portland cement, two parts sand, and only a sufficient amount of water to make a workable plastic mix. Retempered grout shall not be used.

TP-212 MEASUREMENT AND PAYMENT:

Concrete and other work or materials required by this section shall not be measured and paid separately. Rather, they shall be included in the unit or lump sum bid prices of those items shown on the Bid Schedule that require the inclusion of such materials or work, even if not specifically mentioned within the measurement and payment sections of those particular pay items.

TP-213 SUBMITTALS:

A. Concrete testing laboratory

B. Certification of concrete strength by the concrete supplier and/or proposed concrete mix

C. Curing Compound