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CONSTRUCTION SPECIFICATION Reinforced MT-106-1

Reinforced Concrete

1. SCOPE fabric shall be as defined for the specified style designations. The work shall consist of furnishing, forming, placing, finishing and curing Portland − shall portland cement concrete and furnishing and conform to the requirements of ASTM placing reinforcement as required to Specification C-150 for the specified type. If build the structures as shown on the a type is not specified, Type I, Type II low drawings. alkali, or Type III high early strength shall be used. 2. MATERIALS Air-Entraining Admixtures − Air-entraining Steel Reinforcement admixtures shall conform to the requirements of ASTM C-260. Steel bars for concrete reinforcement shall be grade 40, 50, or 60 deformed bars Aggregates − Concrete aggregates shall conforming to one of the following conform to the requirements of ASTM C-33. specifications: Where aggregates conforming to these specifications are not obtainable, aggregates • Deformed and plain billet-steel bars for that have been shown by tests or by actual concrete reinforcement—ASTM A-615 service to produce concrete of the required • Rail-steel deformed bars for concrete strength, durability, watertightness, and reinforcement—ASTM A-996 abrasion resistance may be used if • Axle-steel deformed bars for concrete authorized by the Engineer. reinforcement—ASTM A-996 Concrete aggregates approved for use by the Dowels shall be plain round bars Montana Highway Department are conforming to the same specifications listed acceptable. above for steel bars. − Water shall be clean and free from Fabricated deformed steel bar mats for injurious amounts of oil, salt, acid, alkali, concrete reinforcement shall conform to the organic matter, or other deleterious requirements of ASTM A 184. substances.

Plain steel welded wire reinforcement for Storage of Materials − Steel reinforcement concrete reinforcement shall conform to the stored at the site of the work shall be stored requirements of ASTM A 185. above the ground surface on platforms, skids, or other supports and shall be Deformed steel welded wire reinforcement protected from mechanical injury and for concrete reinforcement shall conform to . the requirements of ASTM A 497. Cement and aggregate shall be stored at the -coated steel bars for concrete site in such a manner as to prevent reinforcement shall conform to the deterioration or intrusion of foreign matter. requirements of ASTM A 775. Damaged materials will be rejected and not Gauges, diameters, spacing, and permitted to be used in the work. arrangement of wires for welded steel wire

USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-2

3. BAR REINFORCEMENT 6. SUPPORTING REINFORCEMENT

Reinforcing bars may not be field milled or Reinforcement shall be accurately placed field bent unless specifically authorized by and secured in position in a manner that will the Engineer. All bends shall be made in prevent its displacement during the accordance with standard approved practice placement of concrete. Tack welding of bars and by approved machine methods. All will not be permitted. bends shall be made without heating. Bars with kinks, cracks, or improper bends will Metal chairs, metal hangers, metal spacers be rejected. and concrete chairs may be used to support the reinforcement. Metal hangers, spacers 4. SPLICING BAR REINFORCEMENT and ties shall be placed in such a manner that they will not be exposed in the finished The length of splices of reinforcing bars concrete surface. The legs of metal chairs or shall be as shown on the drawings. When side form spacers that may be exposed on not shown on the drawings, the length of any face of slabs, , beams or other splices shall provide an overlap equal to at concrete surfaces shall have a protective least 36 diameters of the smaller bar being coating or finish by means of hot dip spliced. galvanizing, epoxy coating, plastic coating, or be . Metal chairs and 5. SPLICING WELDED WIRE spacers not fully covered by a protective REINFORCEMENT coating or finish shall have a minimum cover of 3/4-inch of concrete over the Unless otherwise specified, welded wire unprotected metal portion except for those fabric shall be spliced in the following with plastic coatings may have a minimum manner: cover of 1/2-inch of concrete over the Adjacent sections shall be spliced end to unprotected metal portion. end (longitudinal lap) by overlapping a chairs shall be minimum of one full mesh plus 2 inches manufactured of the same class of concrete plus the length of the two end overhangs. as that specified for the structure and shall The splice length is measured from the have tie wires securely anchored in the chair end of the longitudinal wires in one or a V-shaped groove at least 3/4-inch in piece of fabric to the end of the depth molded into the upper surface to longitudinal wires in the lapped piece of receive the steel bar at the point of support. fabric. Precast concrete chairs shall be clean and Adjacent sections shall be spliced side to moist at the time concrete is placed. side (transverse lap) a minimum of one 7. PLACING REINFORCEMENT full mesh plus 2 inches. The splice length shall be measured from the The following tolerances will be permitted centerline of the first longitudinal wire in in the placement of bars as shown on the one piece of fabric to the centerline of drawings: the first longitudinal wire in the lapped piece of fabric.

USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-3

TABLE 1

Maximum Net Water Content Minimum Cement Content

(gallons/bag) (bags/cubic yard) Without Air With Air Without Strength With Strength Class of Concrete Entrainment Entrainment Test Test 3000 7 6 6 5 4000 6 5 6.5 6 Note: A bag of cement weighs 94 pounds.

7. PLACING REINFORCEMENT or other corrosive (continued) accelerators shall not be used unless otherwise specified. Variation in protective cover: The maximum gallons of water per bag of 1/4 inch for 2-inch cover cement and the minimum number of bags of 1/2 inch for 3-inch cover cement per cubic yard of concrete for the specified class of concrete shall be as Variation of spacing: tabulated in Table 1.

1/12 of indicated spacing Concrete mixtures shall be designed to use a maximum size of coarse aggregate of 1-1/2 Before reinforcement is placed, the surfaces inches. The proportioning of cement, sand, of the bars and fabric and any metal supports and coarse aggregate shall produce a shall be cleaned to remove any loose, flaky concrete mixture, neither too sandy nor too , mill scale, oil, grease or other coatings harsh, that will work readily into the corners or foreign substances. After placement, the and angles of the forms and around reinforcement shall be maintained in a clean reinforcement when consolidated, but will condition until it is completely embedded in not segregate or exude free water during the concrete. On structures exceeding 2 consolidation. cubic yards in concrete volume, the subgrade and placement of the reinforcing material Unless otherwise specified, the slump at the shall be inspected by the Technician prior to time of placement shall be 3 to 5 inches. Air placing the concrete. content by volume shall be 5-7% of the volume of the concrete. 8. DESIGN OF CONCRETE MIX 9. QUALITY OF CONCRETE Concrete shall be classified as shown in Table 1. Control − Prior to placement of any concrete, the Contractor shall furnish a Concrete shall be composed of portland statement to the Technician giving the cement, fine and coarse aggregates, water, proportions by dry weight of cement, and unless otherwise specified, an air- aggregates, water and admixtures that they entraining admixture mixed in such intend to use. If requested by the Technician, proportions so as to produce the specified the Contractor shall furnish evidence minimum compressive strength at the end of satisfactory to the Technician that the 28 days. proportions selected will produce concrete of the quality specified. The materials and

USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-4

proportions so stated shall constitute the One strength test, consisting of three test "job mix." cylinders, shall be made for (1) each day's run or (2) for each 25 cubic yards of After a job mix has been approved, neither concrete placed, or fraction thereof. the source, character, grading of the aggregates nor the type or brand of cement A record shall be made of the particular load or admixture shall be changed without prior of concrete tested, and the exact location in notice to the Technician. If such changes are the work at which each load represented by a necessary, no concrete containing such new strength test is deposited. or altered materials shall be placed until the Technician has approved a revised job mix. In the event that concrete tested in accordance with the requirements stated 10. INSPECTION AND TESTING above fails to meet the strength requirements of these specifications, the contractor shall The Technician shall have free entry to the provide an acceptable new or adjusted mix. plant and equipment furnishing concrete. Proper facilities shall be provided for the 11. HANDLING AND MEASUREMENT Technician to inspect materials, equipment, OF MATERIALS and processes and to obtain samples of the concrete. All tests and inspections will be Materials shall be stockpiled and batched by conducted so as not to interfere methods that will prevent segregation or unnecessarily with manufacture and delivery contamination of aggregates and insure of the concrete. accurate proportioning of the ingredients of the mix. If specified in the special provisions, standard tests of the compressive strength of Cement shall be measured by weight or in the concrete will be made by the Contractor bags of 94 pounds each. When cement is from concrete test cylinders cast by the measured in bags, no fraction of a bag shall Technician in conformance with ASTM C- be used unless weighed. 31. The Contractor shall provide cylinder molds and shall have the cylinders tested by Aggregates shall be measured by weight. an approved laboratory (the Contractor Mix proportions shall be based on saturated, bearing the costs of such testing). surface-dry weights. The batch weight of each aggregate shall be the required One strength test shall consist of three saturated, surface-dry weight plus the weight standard cylinders made from a composite of surface moisture it contains. sample secured from a single load of concrete in accordance with ASTM C-172 Water shall be measured, by volume or by and tested at 28 days. The test results at 28 weight, to accuracy within 1% of the total days shall be the average of the strength of quantity of water required for the batch. three specimens determined in accordance Admixtures shall be measured within a limit with ASTM C-39, except that if one of accuracy of 3%. specimen shows manifest evidence of improper sampling, molding, or testing, it 12. MIXERS AND MIXING shall be discarded and the strengths of the remaining two specimens shall be averaged. Concrete may be furnished by batch mixing Should more than one specimen representing at the site of the work or by ready-mix a test show such defects, the entire test shall methods. be discarded. USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-5

Mixers shall be capable of thoroughly the batch and the time the cement was mixing the concrete ingredients into a introduced to the aggregates. uniform mass and of discharging the mix without segregation. 13. FORMS

Concrete shall be uniform and thoroughly Forms shall be of , plywood, steel, or mixed when delivered to the work site. other approved material and shall be mortar Variations in slump of more than l inch tight. The forms and associated false-work within a batch will be considered evidence shall be substantial, unyielding and shall be of inadequate mixing and shall be corrected constructed so that the finished concrete will by changing batching procedures, increasing conform to the specified dimensions and mixing time, changing mixers, or other contours. Form surfaces shall be smooth and means. free from holes, dents, sags or other irregularities. Forms shall be coated with a For stationary mixers, the mixing time after non-staining form release agent before being all cement and aggregates are in the mixer set into place. drum shall be not less than 1-1/2 minutes. When concrete is mixed in a truck mixer, Metal ties or anchorages within the forms the number of revolutions of the drum or shall be equipped with cones, she-bolts or blades at mixing speed shall be not less than other devices that permit their removal to a 70 nor more than 100. depth of at least 1 inch without injury to the concrete. Ties designed to break off below Unless otherwise specified, volumetric the surface of the concrete shall not be used batching and continuous mixing at the without cones. construction site will be permitted. The batching and mixing equipment shall All edges that will be exposed to view when conform to the requirements of ASTM the structure is completed shall be Specification C-685 and shall be chamfered, unless finished with molding demonstrated prior to placement of concrete, tools. by tests with the job mix, to produce concrete meeting the specified proportioning 14. PREPARATION OF FORMS AND and uniformity requirements. Concrete made SUBGRADE by this method shall be produced, inspected, Prior to placement of concrete the forms and and certified in conformance with Sections subgrade shall be free of chips, sawdust, 6, 7, 8, 13, and 14 of ASTM Specification debris, water, ice, snow, extraneous oil, C-685. mortar, or other harmful substances or No mixing water in excess of the amount coatings. The temperature of all surfaces to called for by the job mix shall be added to be in contact with the new concrete shall be the concrete during mixing or hauling or no colder than 40 degrees Fahrenheit. Any after arrival at the delivery point. oil on the reinforcing steel or other surfaces required to be bonded to the concrete shall When truck ready-mixed or truck-mixed be removed. Rock surfaces shall be cleaned concrete is used, the Contractor shall submit by air-water cutting, wet sandblasting or to the Technician, with each mixer load, a wire brush scrubbing, as necessary, and shall certified delivery ticket giving the quantities be wetted immediately prior to placement of of cement, fine aggregate, coarse aggregate, concrete. Earth surfaces shall be firm and water, and admixtures, if any, contained in damp. Placement of concrete on mud, dried

USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-6

earth or un-compacted fill or frozen horizontal layers not more than 20 inches subgrade will not be permitted. thick. Concrete shall not be dropped more than 5 feet vertically unless suitable Items to be embedded in the concrete shall equipment is used to prevent segregation. be positioned accurately and anchored Hoppers and chutes, pipes or "elephant firmly. trunks" shall be used as necessary to prevent segregation and the splashing of mortar on Weep holes in walls or slabs shall be formed the forms and reinforcing steel above the with non-ferrous materials. layer being placed.

15. CONVEYING Immediately after the concrete is placed in the forms, it shall be consolidated by Concrete shall be delivered to the site and spading, hand tamping or vibration as discharged into the forms within 1-1/2 hours necessary to insure smooth surfaces and after the introduction of the cement to the dense concrete. Each layer shall be aggregates. In hot weather or under consolidated to insure a monolithic bond conditions contributing to quick stiffening of with the preceding layer. If the surface of a the concrete, or when the temperature of the layer of concrete in place sets to the degree concrete is 85 degrees Fahrenheit or above, that it will not flow and merge with the the time between the introduction of the succeeding layer when spaded or vibrated, cement to the aggregates and discharge shall the Contractor shall discontinue placing not exceed 45 minutes. concrete and shall make a construction joint The Technician may allow a longer time, according to the procedure specified herein. provided the setting time of the concrete is If placing is discontinued when an increased a corresponding amount by the incomplete horizontal layer is in place, the addition of an approved set-retarding unfinished end of the layer shall be formed admixture. In any case, concrete shall be by a vertical bulkhead. conveyed from the mixer to the forms as rapidly as practicable by methods that will 17. CONSTRUCTION JOINTS prevent segregation of the aggregates or loss of mortar. Construction joints shall be made at the locations shown on the drawings. If 16. PLACING construction joints are needed which are not shown on the drawings, they shall be placed Concrete shall not be placed until the in locations approved by the Technician. subgrade; forms and steel reinforcement have been inspected and approved by the Where a feather edge would be produced at Technician. The Contractor shall give a construction joint, as in the top surface of a reasonable notice to the Technician each sloping , an insert form shall be used so time he or she intends to place concrete. that the resulting edge thickness on either side of the joint is not less than 3 inches. The concrete shall be deposited as closely as possible to its final position in the forms and In walls and , as each lift is shall be worked into the corners and angles completed, the top surfaces shall be of the forms and around all reinforcement immediately and carefully protected from and embedded items in a manner to prevent any condition that might adversely affect the segregation of aggregates or excessive hardening of the concrete. laitance. Formed concrete shall be placed in USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-7

Steel tying and form construction adjacent to brazed or welded. Joints in rubber or plastic concrete in-place shall not be started until waterstops shall be cemented, welded or the concrete has cured at least 12 hours. vulcanized as recommended by the Before new concrete is deposited on or manufacturer. against concrete that has hardened, the forms shall be retightened. New concrete shall not 20. REMOVAL OF FORMS be placed until the hardened concrete has cured at least 12 hours. Forms shall be removed in such a way as to prevent damage to the concrete. Supports Surfaces of construction joints shall be shall be removed in a manner that will cleaned of all unsatisfactory concrete, permit the concrete to take the stresses due laitance, coatings or debris by washing and to its own weight uniformly and gradually. scrubbing with a wire brush or wire broom or by other means approved by the Forms shall not be removed sooner than the Technician. The surfaces shall be kept moist following minimum times after the concrete for at least 1 hour prior to placement of the is placed. These periods represent new concrete. cumulative number of days and fractions of days, not necessarily consecutive, during 18. EXPANSION AND CONTRACTION which the temperature of the air adjacent to the concrete is above 50 degrees Fahrenheit. Expansion and contraction joints shall be made only at locations shown on the Element Time drawings. Beams, arches--supporting 14 days Exposed concrete edges at expansion and forms and shoring contraction joints shall be carefully tooled or chamfered, and the joints shall be free of Conduits, deck slabs--supporting 7 days mortar and concrete. Joint filler shall be left (inside) forms and shoring exposed for its full length with clean and Conduits, (outside forms), 24 hours true edges. sides of beams, small structures Preformed filler shall be Columns, walls, spillway 7 days held firmly in the correct position as the risers--with side or vertical load concrete is placed. Columns, walls, spillway risers When open joints are specified, they shall be --with no side or vertical load: constructed by the insertion and subsequent removal of a wooden strip, metal plate or Concrete supporting more 7 days other suitable template in such a manner that than 30 feet of wall in place the corners of the concrete will not be above it chipped or broken. The edges of open joints shall be finished with an edging tool prior to Concrete supporting 20 to 30 3 days removal of the joint strips. feet of wall in place above it 19. WATERSTOPS

Waterstops shall be held firmly in the correct position as the concrete is placed. Joints in metal waterstops shall be soldered, USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-8

Element (continued) Time Joints and edges on unformed surfaces that will be exposed to view shall be chamfered Concrete supporting not 24 hours or finished with molding tools. more than 20 feet of wall in place above it1 23. CURING

1Age of stripped concrete shall be at least 7 days Concrete shall be prevented from drying for before any load is applied other than the weight of the a curing period of at least 7 days after it is or wall itself and the forms and scaffolds for succeeding lifts. placed. Exposed surfaces shall be kept continuously moist for the entire period, or 22. FINISHING FORMED SURFACES until curing compound is applied as specified below. All concrete surfaces shall be true and even and shall be free from open or rough spaces, Moisture shall be maintained by sprinkling, depressions or projections. flooding or fog spraying or by covering with continuously moistened canvas, cloth mats, Immediately after the removal of the forms: straw, sand or other approved material. Wood forms left in place during the curing a. All fins and irregular projections shall be period shall be kept continuously wet. removed from exposed surfaces. Formed surfaces shall be thoroughly wetted b. The holes produced on all surfaces by immediately after forms are removed and the removal of form ties, cone-bolts, and shall be kept wet until patching and repairs she-bolts shall be cleaned, wetted and are completed. Water or covering shall be filled with a dry-pack mortar consisting applied in such a way that the concrete of one part portland cement, three parts surface is not eroded or otherwise damaged. sand that will pass a No. 16 sieve, and just sufficient water to produce a Concrete, except at construction joints, may consistency such that the filling is at the be coated with an approved curing point of becoming rubbery when the compound in lieu of continued application material is solidly packed. of moisture except as otherwise specified in the special provisions. The compound shall 22. FINISHING UNFORMED be sprayed on the moist concrete surfaces as SURFACES soon as free water has disappeared, but shall not be applied to any surface until patching, All exposed surfaces of the concrete shall be repairs and finishing of that surface are accurately screeded to grade and then wood completed. The compound shall be applied or magnesium float finished, unless at a uniform rate of not less than 1 gallon per specified otherwise. 150 square feet of surface and shall form a continuous adherent membrane over the Excessive floating or troweling of surfaces entire surface. Curing compound shall be while the concrete is soft will not be thoroughly mixed before applying and permitted. continuously agitated during application. Curing compound shall not be applied to The addition of dry cement or water to the surfaces requiring a bond to subsequently surface of the screeded concrete to expedite placed concrete, such as construction joints, finishing will not be allowed. shear plates, reinforcing steel and other embedded items. If the membrane is damaged during the curing period, the

USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-9

damaged area shall be re-sprayed at the rate 26. CONCRETING IN HOT WEATHER of application specified above. Surfaces covered by the membrane shall not be The Contractor shall apply effective means trafficked unless protected from wear. to maintain the temperature of the concrete below 90 degrees Fahrenheit during mixing, 24. REMOVAL AND REPLACEMENT conveying and placing. OR REPAIR Formed surfaces shall be kept completely When concrete is honeycombed, damaged or and continuously wet for the duration of otherwise defective, the Contractor shall curing period (prior to, during and after form remove and replace the structure or removal) or until curing compound is structural member containing the defective applied. concrete or, where feasible, correct or repair the defective parts. The Technician will Concrete surfaces, especially flat work determine the required extent of removal, placed with large areas of surface, shall be replacement or repair. covered as soon as the concrete has sufficiently hardened and shall be kept 25. CONCRETING IN COLD continuously wet for at least 24 hours of the WEATHER curing period. This protective method may be continued for the required curing period Concrete shall not be mixed nor placed or until curing compound is applied. when the daily minimum atmospheric temperature is less than 40 degrees Moist curing may be discontinued before the Fahrenheit unless facilities are provided to end of the curing period if white pigmented prevent the concrete from freezing. The curing compound is applied immediately, in temperature of the concrete at the time of accordance with the procedures specified in placing shall not be less than 50 degrees Section 23. Fahrenheit nor more than 90 degrees Fahrenheit. Concrete shall not be deposited 27. MEASUREMENT AND PAYMENT on frozen ground nor in forms containing ice (Used only if applicable) or frost. The use of accelerators or antifreeze compounds will not be allowed. For items of work for which specific unit prices are established, reinforced concrete The air and forms in contact with the will be measured to the neat lines shown on concrete shall be maintained at temperatures the drawings and the volume of concrete greater than 50 degrees Fahrenheit but less will be computed to the nearest 0.1 cubic than 90 degrees Fahrenheit for at least 5 yard. Measurement of concrete placed days and at a temperature above freezing for against the sides of an excavation without the remainder of the specified curing period. the use of intervening forms will be made Concrete permitted to be cured with curing only to the neat lines or pay limits shown on compounds shall be provided the same the drawings. No deduction in volume will protection against freezing and low be made for chamfers, rounded or beveled temperatures as provided herein. No fire or edges or for any void or embedded item that excessive heat shall be permitted near or in is less than 3 cubic feet in volume. direct contact with concrete at any time. Payment for each item of concrete will be made at the agreed-to unit price or the agreed-to lump sum, whichever is applicable, for that item. Such payment will USDA-NRCS-Montana November 2014 CONSTRUCTION SPECIFICATION Reinforced Concrete MT-106-10 constitute full compensation for all labor, materials, including steel, equipment, transportation, tools, forms, falsework, bracing and all other items necessary and incidental to the completion of the work.

USDA-NRCS-Montana November 2014