8−55807.05.3 Block and Brick Masonry. The accepted quantities of "Concrete Block Masonry" and/or "Brick Masonry" will be paid for at their respective contract unit prices per cubic yard or per square foot, as the case may be, as listed in the Proposal. The prices so-stated constitute full and complete compensation for all labor, materials and equipment, and all incidental s required to finish the work, complete and accepted by the Engineer. Filling material for the interior of the wall, reinforcing steel, and concrete or mortar copings, shall be considered as included in the price paid for number of cubic yards or square feet of block or brick masonry actually placed.
807.05.4 Concrete Backing. The accepted quantity of "Conc rete Backing" of stone fascia
walls will be paid for at the contract unit price per cubic yard as listed in the Proposal. The price so- stated constitutes full and complete compensation for all labor, materials, and equipment, and all incidentals required to finish the work, complete and accepted by the Engineer.
808.01 DESCRIPTION. This work consists of the provision of cast-in-place concrete in bridges,
walls, culverts, and other miscellaneous structures at the locations and to the details indicated on the Plans, or as directed by the Engineer, all in accordance with these Specifications. The work includes structures constructed by cast-in-place methods using either plain or reinforced concrete, or a combination of both. 808.01.1 Related Items of Work Covered Elsewhere. Related items of work covered in other Sections of these Specifications include the following:
a.SECTION 810; REINFORCING STEEL
b.SECTION 811; PAVEMENT SUBDRAINS AND WALL DRAINS.
c.SECTION 812; WATER STOPS AND FLASHINGS
d.SECTION 823; ROADWAY JOINTS, EXPANSION AND FIXED
808.02 Materials.
808.02.1 Concrete. All materials required for the producti on and curing of structure concrete shall
conform to the applicable requirements of SECTIONS 601 and M.02; PORTLAND CEMENT CONCRETE and SECTION 605; CONCRETE WITH CALCIUM NITRITE BASED CORROSION INHIBITOR , respectively, of these Specifications.
808.02.2 Joint Fillers and Sealants. The following materials shall conform to the applicable
requirements of the indicated Subsections of PART M; MATERIALS : 8−56
a.Subsection M.02.10.1; Preformed Joint Filler.
b.Subsection M.02.10.2; Poured Joint Sealer .
c.Subsection M.02.10.3; Preformed Neoprene Compression Seals.
d.Subsection M.02.11.1; Preformed Expansion Joint Filler , the bituminous type; the non-extruding type; and the polyethylene foam joint filler type.
e.Subsection M.02.11.2; Joint Seal . (Poured and Caulked Types)
f.Subsection M.02.11.3; Mastic Joint Sealer.
g.Subsection M.02.11.5; Polyurethane Joint Sealant .
h.Subsection M.02.11.6; Polyurethane Elastomeric Joint Sealant .
808.03 Construction Methods.
808.03.1 General. The requirements for classification, proportioning, batching, mixing, transportation, placing, curing, and testing of concrete shall conform to the requirements of SECTION 601; PORTLAND CEMENT CONCRETE.
808.03.2 Footings. Preparation of foundations shall conform to the requirements of SECTION
203; STRUCTURE EXCAVATION AND BACKFILL . No concrete shall be placed until after the Engineer has approved the depth and dimensions of the excavation, the character of the material and the condition of the foundation. No footing shall be supported partially on rock and partially on soil. The rock shall be excavated as necessary to allow the placement of 12 inches of gravel in accordance with Subsection 203.03.1; Excavation . The Engineer may direct, in writing, such changes in dimensions or elevations of footi ngs as may be necessary to obtain satisfactory foundations. The Plans will be revised accordingly.
a.Foundations Under Water. When required by the Contract Special Provisions, foundations to be constructed under water shall be inspected by divers hired by the Contractor independently and solely for the purpose of the inspec tion requirements of the Contract. The diver shall be a professional engineer registered by the State of Rhode Island and shall be appropriately certified to perform the intended work. In general, the diver's tasks shall include inspection of the excavations for foundations to determine their completeness and suitability for the placement of concrete, inspection of the drilling and grouting operations for any dowels that may be specified, and inspection of the tremie placement operations to ensure that the concrete placement is proceeding properly and is completed in accordance with applicable contract Specifications. The diver shall be responsible to report any discrepancies in materials or workmanship to the Engineer. The diver shall record his/her findings by written and photographic methods and a 8−57final report of findings, recommendations and actions taken shall be prepared for the Engineer. Measurement and payment for the diving services shall be as outlined in the Special Provisions. 808.03.3 Falsework and Centering. All falsework or centering shall be adequate for the type of construction involved and shall conform to the requirements of Paragraph 3.2; Falsework and Forms, of the AASHTO Standard Specifications for Highway Bridges, latest revision. The Contractor shall submit all shop drawings for falsework and centering, including design computations formally signed and sealed by the C ontractor's Rhode Island Registered Professional Engineer, all in accordance with Subsection 105.02; Plans and Shop Drawings , of these Specifications. The Contractor's professional engineer shall certify that the falsework system has been assembled and constructed according to the approved falsework drawings, prio r to placing loads on such falsework. When structures are to be constructed over ra ilroad tracks, the centering shall also conform to the requirements of the railroad company as to temporary operating clearances, safety and design.
808.03.4 Forms.
a.General. When required, the Contractor shall prepare detailed plans for all important forms. This requirement includes design co mputations formally signed and sealed by the Contractor's Rhode Island Registered Professional Engineer, and otherwise in accordance with Subsection 105.02; Plans and Shop Drawings , of these Specifications. Such plans shall be approved by the Engineer before any work is started on construction of the forms. So-called snap ties shall not be used, and removable cones shall be of minimum diameter. Where forms are to be suspended from the structural steel girders, snap-tie hangers, wires or other devices that cannot be readily adjusted to provide mortar-tight joints will not be approved. Slab forms shall not bear on interior diaphragms. Forms shall not be installed over steel suppor ting members until after the steel erection and touch-up painting is completed. Provision shall be included in the form for a standard 3/4-inch symmetrical chamfer at all square entrant concrete corners unless otherwise indicated on the Plans.
b.Wood Forms. All face forms shall be constructed of lumber 3/4-inch or more in thickness lined with pressed wood-fiber or plywood not less than 1/4-inch in thickness. Sheet metal (preferably noncorrosive) of approved gauge may be substituted. As an alternate method of construction, face forms may be made up of plywood, 5/8-inch or more in thickness, without backing boards if properly designed and supported. Such alternate construction shall provide a rigid form which w ill prevent unacceptable deformations in the finished concrete surface. All pressed wood-fibre or plywood forms shall be suitably tempered or waterproofed at the time of manufacture to prevent the absorption of moisture and shall be of an approved type. 8−58 When lining is used, the wood forms shall be of the usual construction with the boards closely spaced. The lining sha ll be in sheets of maximum useable size and shall be applied smooth side to the concrete. Joints between panels shall be taped or filled to provide a smooth, tight form surface. Metal ties or anchorages which are required within the forms to hold them to correct alignment and location shall be so constructed that the metal work can be removed to a depth of at least 2 inches from the exposed surface of the concrete without causing injury to such surface by spalling or otherwise. When permitted for secondary forms, all wires, upon removal of the forms, shall be cut back at least ½-inch from the face of the concrete with sharp chisels or nippers. All fittings for metal ties shall be of such design that, upon their removal, the cavities which are left shall be of the smallest possible size. The cavities shall be filled with cement mortar of fine aggregate and cement in the proportion that has been employed for the particular class of concrete treated, and the surface left smooth, even and uniform in color. Formwork lines shall be straight and true and forms shall be mortar-tight and well tied and braced to prevent bulging. Block shims or wedges must be properly secured before placing concrete. Formwork shall be treated with a form release agent approved by the Engineer or be saturated with water just before placing concrete. The form release agent used shall not discolor or otherwise injuriously affect the concrete surface or subsequent finish. Release agents must be applied to the forms before the reinforcement is placed. All excess release agent shall be removed from the face surfaces, and the ties and reinforcement shall be thoroughly cleaned with an approved solvent where necessary.
c.Metal Forms. The applicable requirements for wood forms shall apply to metal forms. The metal used for forms shall be of such thickness that the forms will remain true to shape. All bolt and rivet heads shall be countersunk. Clamps, pi ns or other connecting devices shall be designed to hold the forms rigidly together and to allow removal without injury to the concrete. Metal forms which do not present a smooth surface or line up properly shall not be used. Special care shall be exercised to keep metal forms free from rust, grease or other foreign matter which will discolor the concrete. 808.03.5 Placing Concrete (Conventional Method).
a.General. In preparation for the placing of concrete, all sawdust, chips, standing water and other construction debris and extraneous matter shall be removed from the interior of forms. Struts, stays and braces, serving temporarily to hold the forms in correct shape and alignment, pending the placing of concrete at their locations, shall be removed when the concrete placing has reached an elevation rendering their service unnec essary. These temporary members shall be entirely removed from the forms and not buried in the concrete, unless directed otherwise by the Engineer. Any hardware allowed to remain in the formwork shall be cut back to the design cover for reinforcement. The resulting recess in the concrete surface shall then be filled with a patching mortar approved by the Engineer. The Contractor will be required to notify the Engineer twenty-four hours in advance of placing concrete in order to provide ample time for the inspection of forms, steel reinforcement, 8−59materials and equipment. Concrete shall be placed and consolidated by me thods that will neither cause segregation of materials nor displacement of reinforcement and that will result in a dense homogeneous concrete which is free of voids and rock pockets. Prior to the actual placement of concrete, the Engineer may require the Contractor to demonstrate the capability of the equipment to convey the concrete mixture to maintain the specified quality. If the quality of concrete reaching the form is found to be inadequate as a result of the method of concrete placement, the Engineer may order the work to be discontinued and require the substitution of a satisfactory method of concrete placement. The use of aluminum for chutes on pipes shall not be permitted. Open chutes shall be of metal or metal lined. Where steep slopes are required, the chutes shall be equipped with baffles erected in short lengths to slow the movement of concrete. Concrete shall not be dropped a distance of more than 5 feet, and special care shall be taken to fill each part of the form by depositing the concrete as near to its final position as possible. Where placing operations would involve dropping the concrete more than 5 feet, such as piers, columns, thin walls, etc., it shall be deposited through sheet metal or other approved pipes. As far as practical, pipes shall be kept full of concrete during placing, and their lower ends shall be kept buried in the newly placed concrete. All chutes and pipes shall be kept clean and free from coatings of hardened concrete by thoroughly flushing with water after each run. Concrete shall be consolidated by mechanical, high frequency internal or external vibrators, or both, in a manner acceptable to the Engineer. Vibrators shall be of a type and size suited to the purpose. Handheld vibrators shall be equipped with rubber tipped heads when used to consolidate around epoxy-coated reinforcement. Vibrators shall be manipulated so as to thoroughly work the concrete around the reinforcement and embedded fixtures and into the corners and angles of forms. The vibration at any point shall of sufficient duration to accomp lish thorough consolidation but shall not be prolonged to the point where segregation or bleeding occurs. Vibration shall not be applied directly to, or through the reinforcement to sections or layers of concrete which have hardened to the degree the concrete ceases to be plastic under such vibration. Vibrators shall not be used to transport concrete in the forms. Concrete shall be placed in horizontal layers not more than 12 inches thick, except as hereinafter provided. When less than a complete layer is placed in one operation, it shall be terminated in a vertical bulkhead. Each layer shall be placed and consolidated before the preceding course has taken initial set to avoid the formation of a cold joint with the preceding course. In case the placing of concrete is temporarily delayed, the concrete shall be covered immediately and kept moist to retard initial set until placement can resume. In case the placing of concrete is temporarily discontinued, a constructi on joint shall be formed immediately. Laitance and other objectionable material shall be cleaned from the new construction joint when placement is 8−60 scheduled to resume. To avoid visible joints as far as possible upon exposed faces, the top surface of the concrete adjacent to the forms shall be smoothed with a trowel. Where a "feather edge" might be produced at a construction joint, as in the sloped surface of a wingwall, an inset form shall be used to produce a blocked-out portion in the preceding layer whic h shall produce an edge thickness of not less than 6 inches in the succeeding layer. Work shall not be discontinued within 18 inches of the top of any face, unless provision has been made for a coping less than 18 inches thick. In such case, and if permitted by the Engineer, the construction joint may be made at the underside of the coping. Immediately following the discontinuance of placing concrete, all accumulations of mortar splashed upon the reinforcing steel and the surface of forms shall be removed. Dried mortar chips and dust shall not be puddled into the unset concrete. If the accumulations are not removed prior to the concrete becoming set, care shall be exercised not to injure or break the concrete-steel bond at and near the surface of the concrete while cleaning the reinforcing steel.
b.Vertical Members. Concrete for columns, substructure and culvert walls, and other similar vertical members shall be placed and allowed to set and settle for a period of time before concrete for integral horizontal members, such as caps, slabs or footings is placed. Such period shall be adequate to allow completion of settlement due to loss of bleed water and shall be not less than 12 hours for vertical members over 15 feet in height and not less than 30 minutes for members over 5 feet but not over 15 feet in height. When friction collars or falsework brackets are mounted on such vertical members and unless otherwise approved, the vertical member shall have been in place at least seven days and shall have attained its specified strength before loads from horizontal members are applied.
c.Slabs. Before any slab concrete is placed, an approved templet and finishing tools shall be on hand for striking off the surface of the slab to the required crown, as shown on the Plans. For bridge deck slabs, refer to SECTION 814; PLACEMENT OF CONCRETE BRIDGE DECKS , of these Specifications.
d.Superstructure. Unless otherwise permitted, no concrete shall be placed in the superstructure until substructure forms have been stripped sufficiently to determine the character of the supporting substructure concrete. Concrete for T-beam or deck girder spans whose depth is less than 4 feet may be placed in one continuous operation or may be placed in two separate operations; first, to the top of the girder stems, and second, to completion. For T-beam or deck girder spans whose depth is 4 feet or more and, unless the falsework is non-yielding, such concrete shall be placed in two operations and at least five days shall elapse after placement of stems before the top deck slab is placed. Concrete for box girders may be placed in two or three separate operations consisting of bottom slab, girder stems and top slab. In either case the bottom slab shall be placed first and, unless otherwise permitted by the Engineer, the top slab shall not be placed until the girder stems have been in place for at least five days.
e.Arch Rings. The concrete in arch rings shall be placed in such a manner as to load the centering uniformly. Arch rings and ribs preferably shall be cast in a single continuous operation. 8−61However, with the permission of the Engineer, they may be divided by radial bulkheads into transverse sections of such size that each section can be cast in a continuous operation. The arrangement of the sections and the sequence of placing shall be as approved by the Engineer and shall be such as to avoid the distortion of the centering and consequent creation of initial stress in the newly placed concrete or its reinforcement. The sections shall be bonded together by suitable keys. Where special key sections are required, the concrete shall be mixed as dry as possible and consolidated by means of vibration. The spandrel walls or columns and the beams shall not be cast until after the centering is struck, and no part of the coping, railing, or floor shall be cast until the spandrel walls or columns are complete.
f.Depositing Concrete Under Water. Concrete shall not be deposited in water except with the approval of the Engineer and under his immediate supervision. In this case the method of placing shall be as specified. Concrete deposited in water shall conform to the applicable requirements of Subsection
601.01 1; Classification, of these Specifications. To prevent segregation it shall be carefully placed in a compact mass in its final position, by means of a tremie or other approved method, and
shall not be disturbed after being deposited. Still water shall be maintained at the point of deposit and the forms under water shall be watertight. For parts of structures under water, when possible, concrete seals shall be placed continuously from start to finish. The surface of the concrete shall be kept as nearly horizontal as practicable at all times. To insure thorough bonding, each succeeding layer of a seal shall be placed before the preceding layer has taken initial set. A tremie shall consist of a tube having a diameter of not less than 10 inches, constructed in sections having flanged couplings fitted with gaskets. The tremies shall be supported so as to permit free movement of the discharge over the entire top surface of the work to permit rapid lowering when necessary to retard or stop the flow of concrete. The discharge end shall be closed with an approved type of foot valve at each start of work, to prevent water entering the tube, and all joints shall be sealed so that the concrete may be discharged into the empty tube. The tremie tube shall be kept full to the bottom of the hopper. When a batch is dumped into the hopper, the flow of concrete shall be induced by slightly raising the discharge end but, always keeping it in the mass of deposited concrete. The flow shall be continuous until the work is completed. Dewatering may not proceed until 7 days after completion of the pour except when prior permission is granted by the Engineer. All laitance or other unsatisfactory material shall be re-moved from the exposed surface by scraping, chipping or other means such that the surface of the concrete will not be injured.
g.Concrete Exposed to Sea Water. Unless shown otherwise on the Plans, no construction joints shall be allowed between ex treme low tide and extreme high tide. In the determination of these ranges due consideration shall be given to wave action, ice formation and other conditions affecting the extreme limits of possible deterioration and disintegration.
h.Cold Weather Concrete. Concrete operations during cold weather shall conform to the requirements of Subsection 601.03.5; Cold Weather Concrete.
i.Hot Weather Concrete. Concrete operations during hot weather shall conform to the 8−62 requirements of Subsection 601.03.6; Hot Weather Concrete.
808.03.6 Placing Concrete by Pumping (Optional Method).
a.Pumping . Placement of concrete by pumping will be permitted as approved by the Engineer. The equipment shall be arranged that no vibrations result which might damage freshly placed concrete. Where concrete is conveyed and placed by mechanically applied pressure, the equipment shall be suitable in kind and adequate in capacity for the work. The operation of the pump shall be such that a continuous stream of concrete without air pockets is produced. When pumping is completed, the concrete remaining in the pipe-line, if such is to be used, shall be ejected in such manner that there will be no contamination of the concrete or separation of the ingredients.
b.Handling and Placing Concrete . Concrete shall be placed so as to avoid segregation of materials and displacement of reinforcement. Prior to the actual placement of concrete, the Engineer may require the Contractor to demonstrat e the capability of the equipment to both convey the concrete mixture and maintain the specified quality. No further verification of the equipment's capability will be required unless evidence of nonunifo rm concrete is observed by the Engineer during placement. Concrete shall not come in contact with aluminum during conveying and placing operations. When concrete pumps are used, the lines shall have a minimum diameter of 5 inches. The specific pumping equipment which the Contractor proposes to use shall be subject to the approval of the Engineer. All chutes, troughs and pipes shall be kept clean and free from coatings of hardened concrete by thoroughly flushing with water after each run; water used for flushing shall be discarded clear of the concrete already in place. Dropping concrete a distance of more than 5 feet or depositing a large quantity at any point and running or working it along the forms shall not be permitted. Special care shall be taken to fill each part of the form by depositing concrete directly in the form as near to its final position as possible; to work the coarser aggregates back from the face of the concrete; and to force the c oncrete under and around the reinforcement. After the concrete has taken its initial set, care shall be exercised to avoid jarring the forms or placing any strain on the ends of projecting reinforcement.
c.Design Mix. The Contractor shall have the option to submit for approval by the Engineer a pump mix design formula of the concrete mixtur e to be used with the specific pumping equipment. The concrete mixture shall meet the specific requirements of Subsection 601.03.1; Proportioning , for air content, cement factor, and slump for the various classes of concrete specified.
d.Placing Concrete Under Water. Concrete placed under water shall be placed continuously from start to finish. The surface of the concrete shall be kept as nearly horizontal as practicable. To insure thorough bonding, each succeeding layer of seal shall be placed before the preceding layer has taken initial set. For large pours, more than one tremie or pump shall be used to insure compliance with this requirement. 8−63808.03.7 Expansion, Contraction and Construction Joints.
a.Concrete Joints.
1.General. The type and details of joints and joint fillers in concrete shall be as shown on the Plans. Joints shall be filled or open. Filled joints may be the poured type or filled with a premoulded filler. Materials for joint fillers and sealants are specified in Subsection M.02.10 of these Specifications.
2.Flashing and Water Stops. Metal flashing or flexible water stops shall be furnished and placed as shown on the Plans. They shall be spliced, welded or soldered to form continuous watertight joints, and shall conform to the requirements of SECTION 812; WATER STOPS AND FLASHING .
3.Construction Joints. In order to reduce the size of pours or for other construction reasons, additional joints may be provided at locations approved by the Engineer. Particular care shall be taken with all bonded construction joints to obtain a bond between subsequent pourings. All laitance and debris shall be carefully chipped and cleaned from the surface of the hardened concrete. The contact ar eas shall be cleaned with a wire brush, moistened with water and covered with a coating of mortar or neat cement grout. The new concrete shall be placed before the grout has attained its initial set and shall be carefully spaded into position. Shear keys, steel dowels or inclined reinforcement approved by the Engineer shall be used where necessary to transmit shear, or bond the two sections together.
4.Contraction Joints. Where a definite thickness of joint filler is not indicated on the Plans, bond between adjacent surfaces shall be prevented by coating the surface of the concrete in the section first placed with an approved bond breaking material or a sheet of approved nonstaining fibrous paper, or both, using the coating material as a cementing medium.
5.Expansion Joints. Joints to be sealed shall be thoroughly cleaned of all foreign matter. Joint fillers shall be applied in accordance with Subsection 808.03.8; Para. a , below.
808.03.8 Joint Fillers and Sealants.
a.Preformed Polyethylene Foam Joint Filler.
1.Preparation. Joints shall be absolutely dry and thoroughly cleaned of all deleterious material prior to placing the joint fillers and sealants.
2.Installation. The thickness of the joint filler shall be as indicated on the Plans. The preformed joint filler shall be installed in strict accordance with the manufacturer's recommenda-tions.
b.Mastic Joint Sealer.
1.Preparation. Joints shall be absolutely dry and thoroughly cleaned in accordance with the manufacturer's recommendations prior to placing the joint fillers and sealants. 8−64
2.Approval Requirements. Prior to its use, the Contractor shall furnish notarized certification that the material proposed meets all the requirements of Subsection M.02.11.3 of these Specifications. The State will require proof that the proposed mastic system has a proven record of performance as confirmed by actual field tests and successful installations in New England. Those installations cited must be avail able for inspection by Department personnel. The State may require the Contractor to either conduct laboratory tests at its expense or submit current independent laboratory tests to substantiate compliance with the above requirements.
3.Manufacturer's Representative. The supplier of mastic joint sealer shall furnish the services of a competent field representative of the approved manufacturer, if required to do so by the State. The field representative shall be present at the work site prior to any use of materials to instruct the Contractor, the Inspector or the Engineer on installation and inspection procedures and to inspect the condition of the prepared surfaces. The manufacturer's representative will remain at the job site after work commences until the Inspector or Engineer are satisfied that the work crew has successfully mastered the technique of installing the mastic system.
4.Installation. Installation of the mastic joint sealer shall be in accordance with the directions of the manufacturer. Duplicate copies of said directions shall be forwarded to the job site with each shipment of material.
c.Polyurethane Joint Sealant.
1.Preparation. All joints shall be cleaned of contaminants and impurities to the depth at which the sealant (and backer rod if detailed) is to be installed. Cleaning shall be by grinding, saw cutting blast cleaning (sand or water), mechanical abr ading or a combination of such methods. This operation will provide a sound, clean and frost-free surface for sealant application. All dust, loose particles and other debris shall be blown out with oil free compressed air. An expanded closed cell polyethylene foam rod backup material shall be installed in joints, or an approved bond breaker tape shall be installed if so detailed on the Plans.
2.Application. A primer shall be applied to the concrete surfaces of the joints. The primer shall be in accordance with the recommendation of the sealant manufacturer and shall not be applied to the backup rod or the bond breaker tape. The polyurethane joint sealant shall be applied in strict conformance with the manufacturer's recommendations and in no case thicker than ½-inch. The approximate width to depth ratio shall be 2-to-1 for working joints. The joint shall be tooled using a blunt instrument so that it is slightly concave. A soap solution may be used as a tooling aid.
d.Polyurethane Elastomeric Joint Sealant.
1.Preparation. The preparation requirements for this sealant are identical to those specified above in Para. c.1 of this Subsection for Polyurethane Joint Sealant.
2.Application. A primer shall be applied to the concrete surfaces of the joints. The 8−65primer shall be in accordance with the recommendation of the sealant manufacturer and shall not be applied to the backup rod or the bond breaker tape. The polyurethane elastomeric joint sealant shall be applied in strict conformance with the manufacturer's recommendations. The sealant shall not be applied to joints less t han 1/4-inch in width. The approximate width to depth ratio shall be 2-to-1 for working joints. The application temperature range is 40 OF to 100OF. Sealant shall not be applied when the temperature exceeds these limits. The joint shall be tooled using a blunt instrument so that it is slightly concave. A soap solution may be used as a tooling aid. Any spillage shall be cleaned up immediately in accordance with local regulations and the directions of the Engineer. 808.03.9 Curing Concrete. Portland cement concrete shall be cured in accordance with the requirements of Subsection 601.03.8, Curing , except that all placements designated as mass concrete shall follow the requirements of SECTION 607. The determination of what placements shall be treated as mass concrete shall be in accordance with the requirements of that section. 808.03.10 Removal of Forms, Falsework and Centering. In general, forms for slabs, beams, pier caps and other support members shall not be removed until the concrete has reached the specified 28-day strength as indicated by the compression tests of field cured cylinders. When it is desirable to facilitate surface finish, side forms used on ornamental work, railings, parapets and exposed vertical surfaces (except columns) may be removed after 12 hours. In warm weather, when the average temperature exceeds 50 OF, the following periods for the removal of forms and supports may be used as a guide when field operations are not controlled by cylinder tests: Arch centers (after last pour) 14 days Centering under beams 14 days Deck slabs (over 10-foot spans) 7-14 days Deck slabs (under 10-foot spans) 7 days Columns and slender piers (depending on height) 2-7 days In cold weather, or when the average temperature is below 50 OF, removal of forms and falsework shall be controlled by results of the compression tests on field cured cylinders. Falsework and centering for filled arches shall not be struck until fills behind the abutments have been placed up to the spring line. Falsework supporting the deck of rigid frame structures shall not be removed until fills have been placed back of the vertical legs, in accordance with Subsection 203.03.5; Para. b, Pervious Fill Adjacent to Structures. Centers shall be gradually and uniformly lowered in such a manner as to avoid excessive stresses in any part of the structure. In arch structures of two-or-more spans, the sequence of 8−66 striking centers shall be specified by the Engineer. Arch centering shall be struck and the arch made self-supporting before the railing or coping is placed. 808.03.11 Concrete Finishes.
a.General. All concrete surfaces shall be finished by experienced concrete finishers. Finishes for concrete bridge decks placed by self-propelled machines shall conform to the requirements of SECTION 814 of these Specifications. Otherwise the finishes to be applied to different types of surfaces shall be as follows:
1.Float Finish . Tops of walls, piers, abutments, parapets, safety walks, sidewalks and medians.
2.Rubbed Finish. All exposed surfaces visible in elevation, to 1 foot below final ground line and the underside of concrete slabs outside of the fascia beam unless otherwise indicated on the Plans.
3.Bush-hammered or Sand Blasted . As shown on Plans.
b.Float Finish. Float finish for horizontal surfaces shall be achieved by placing excess concrete in the forms and striking it off with a template or screed, forcing the coarse aggregate below the surface. The surface shall then be finished by a wooden float to a smooth true plane. The area under bearing plates shall be finished as nearly as possible to 1/8-inch above the final elevation and then dressed to a uniform level bearing with a carborundum brick or power grinder after the concrete has sufficiently set.
c.Rubbed Finish. The object of this operation is to obtain a surface that is uniform in texture and appearance and free of all imperfections or depressions due to form marks or other causes. In general, it shall be accomplished in two rubbing, the first performed as soon after the removal of forms as the condition of the surface warrants, and the second after the completion of the curing period and any subsequent work that might damage the finished appearance. The entire surface that is to receive a rubbed finish shall be thoroughly moistened with water and rubbed with a wood float or a fairly coarse carborundum stone, depending on the set of the concrete, to produce a paste on the surface. This rubbing shall be continued as long as necessary to remove form marks and projections and to produce a smooth dense surface without pits or irregularities, but shall not be continued to the extent that it causes noticeable exposure of the coarse aggregate. No wet rubbing shall be done when atmospheric temperatures of 40 OF or less may normally be expected, unless the work is protected by a substantial windproof housing.
d.Bushhammered or Sandblasted Finish . This type of finish consists of removing a depth of mortar from the surfaces of the walls in order to expose the aggregates and present a rough texture in accordance with and to the limits shown on the Plans. The method employed to achieve the desired results shall be by either sandblasting or 8−67bushhammering. No chemical retardant applied to the forms shall be used. Enough surface mortar shall be removed in order to expose the aggregate particles in slight relief and provide an overall surface with a uniform rough texture. Prior to finishing any concrete, the Contractor shall cast a test panel approximately 4 foot by 4 foot in a vertical position with a joint in the form work near the approximate middle of the panel and demonstrate the proposed method. This method shall be satisfactory to the Engineer who shall be the sole judge of its acceptability. In the event the first trial panel does not produce satisfactory results, one or more trial panels shall be cast until a satisfactory finish is obtained. The surfaces to be finished shall be carefully cured. After the forms have been removed all holes shall be patched with an approved mortar and any fins or other protuberances removed to present a roughly even surface. If bushhammering is to be employed, the use of air tools is preferable. No finishing shall be started until the concrete has attained its 28-day strength. Particular care shall be taken when finishing bevels or corners so as not to damage the lines. After the surfaces are fi nished, all dust and loose particles shall be removed by brushing with stiff wire brushes or air blasting.
808.04 Method of Measurement.
808.04.1 Structure Concrete Masonry. "Structure Concrete Masonry" of the types described in this Section will be measured by the number of cubi c yards of such concrete actually provided in
accordance with the Plans and/or as directed by the Engineer.
a.Deductions. Deduction in volume will be allowed for the following elements embedded in concrete:
1.The volume of major structural steel with the exception of steel sheet piling.
2.The volume of timber piles on the basis of 0.8 cubic feet per linear foot of pile.
3.The volume of concrete on combination piles. No deduction in volume will be allowed for reinforcing steel, floor drains, weep holes, drainage holes, expansion joint material and minor structural elements embedded in concrete. 808.04.2 Joint Fillers. "Joint Fillers" of the types described in this Section will be measured by the number of square feet of those materials actually installed in accordance with the Plans and/or as directed by the Engineer. 808.04.3 Joint Sealants. "Joint Sealants" of the types described in this Section will be measured by the number of cubic inches or the number of linear feet, as the case may be, actually installed in accordance with the Plans and/or as directed by the Engineer. 808.04.4 Concrete Finishes. "Rubbed Finish" and "Bushhammered, or Sand Blasted Finish" will be measured by the number of square feet actually applied in accordance with the Plans and/or as directed by the Engineer. Float finish and concrete deck or wearing surface finish will not be
Source: Rhode Island Standard Specifications (Bluebook), 2024 Edition. Pages 389–401 of 826.