SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY — REPAIRS TO STRUCTURE CONCRETE MASONRY
817.01 Description.
This work includes making repairs to structure concrete masonry by removing and disposing deteriorated concrete; furnishing and installing steel reinforcement; preparing bonding surfaces of concrete; replacing the deteriorated concrete with a specified repair material; and finishing and curing to the lines and grades specified at the required locations.
817.02 Materials.
Ensure that all proposed repair materials conform this Subsection and/or are listed on the Department’s Approved Materials List. Pneumatically Applied Mortar (Shotcrete). Use materials for shotcrete that conform to SECTION 601 and SECTION M02, except as modified herein. Produce s hotcrete by either the wet mix process or the dry mix process and conform to the following requirements: Material or Property Value Compressive Strength at 28 days, f′c (psi) As indicated on Plans Maximum Water/Cementitious Ratio 0.45 Minimum Cement Factor (lb/cu yd) 500 Air Content (percent) 5 - 9 Slump (inches) 1 to 3 Determine, recommend, and submit a mix proportion for approval, 28-day compressive strength results, water -cement ratio, and source of materials . S elect mix proportions on the basis of compressive strength tests of specimens continuously moist cured until tested at 28 days or different test age if specified according to ASTM C1604. Sample shotcrete core specimens from shotcreted test panels not earlier than three days after shotcreting. Perform sampling and testing of shotcrete cores in accordance with A STM C1604. Ensure that the c ombined aggregate gradation (fine and coarse) meet s either gradation #1 or #2 of Table 1.1 of ACI 506R, Section 1.5. Premixed and prepackaged concrete products specifically manufactured as a shotcrete product may be provided for the dry mix shotcrete process . Ensure that t he packages contain cement and aggregates conforming to the materials requirement of this Specification, and the product must be listed on the Department ’s Approved Materials List. Materials not previously approved must be submitted to the Engineer. Do not use without written approval. Patching Mortar. Ensure that patching mortar , formulated as for vertical or overhead repairs, as appropriate, conforms to ASTM C928, Rapid Hardening or Very Rapid Hardening Mortar and that it is listed
Part 800 — Bridge Structures August 2025
SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY 800-107 on the Department’s Approved Materials List. Use mortar that is a non-shrink type and chloride free. For repair mortars not previously approved, submit to and the Engineer for written approval before use. Use all materials according to the manufacturer’s recommendations. Reinforcement. Ensure that all reinforcement is galvanized and conforms to SECTION M05. Use welded wire reinforcement that is welded fabric No. 12 gauge wire (minimum size) spaced 2 in. in each direction. Bonding Agent. Use a bonding agent when mortar repairs are specified as listed on the Department’s Approved Materials List. Form and Cast-in-Place Concrete. Use concrete that conforms to SECTION 601. Aggregate. The fine and coarse aggregates must be approved by the Engineer regarding color and texture. Integrally Colored Concrete. Ensure that integrally colored Portland cement concrete conforms to SECTION 601. Integrally Colored Patching Mortar. Use patching mortar that conforms to Subsection 817.02.2. Ensure that the maximum water cement ratio does not exceed 0.40 by weight. Coloring Pigment. Use coloring pigments for integrally colored concrete or patching mortar that meets ASTM C979 and is approved by the Engineer. Use coloring pigments according to the manufacturer ’s recommendations. Portland Cement Bonding Grout Slurry. Use bonding grout slurry that has the cement and mortar sand proportioned 1:1 by volume. Add water in sufficient quantity to form a slurry. Concrete Anchors. Use mechanical concrete anchors that are the hooked type expansion bolts galvanized according to Subsection M05.05.4(c) and has been approved by the Engineer.
Part 800 — Bridge Structures August 2025
800-108 SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY Prototype (Samples). Submit to the Engineer a prototype (1 ft × 1 ft × 3 in. min.) showing color and texture of the concrete and/or mortar required specifically for Repairs to Structural Concrete Masonry with Integrally Colored Concrete or Patching Mortar. Provide, in writing, the mix design and methods for obtaining any required surface finish (e.g., exposed aggregate) for each material. Submit the prototype(s) sufficiently in advance to allow for review and approval of the repair material. The Engineer must approve the pro totypes in writing and, if necessary, gain approval from the Department’s Historic Preservation Specialist before use in production.
817.03 Construction Methods.
Surface Preparation (All Repair Methods). Remove all deteriorated , soft or honeycombed concrete from the areas to be repaired, using suitable power and hand tools, to a uniform depth, sufficient to expose a bonding surface of sound material. Do not use p ower tools that cause or may cause over -breakage of concrete. Ensure that pneumatic/chipping hammers are not heavier than the nominal 30 -lb class. T o remove concrete within 2 in. beneath or around reinforcing steel designated to remain, use pneumatic/chipping hammers or mechanical chipping tools that are not heavier than the nominal 15-lb class. Do not allow t ools to contact reinforcing steel to remain. At the direction of the Engineer, saw cut the perimeter of the area to be repaired parallel to the horizontal and/or vertical axis of the element being repaired to a depth of at least ¾-in. Do not allow any thin or feathered edges. Ensure that areas to be repaired are roughly circular or rectangular in outline. Avoid re - entrant corners and shapes that include acute angles. Saw cut the boundaries of areas to be removed square to a minimum depth of 1 in. Do not allow thin, tapered, or feathered edges. Where reinforcing steel is surrounded by deteriorated concrete or where at least one -half of the rebar surface area is exposed, ensure that the depth of concrete removal includes all deteriorated concrete but not less than that depth necessary to allow for a 1 in. minimum annular clearance around the reinforcing bars. Extend concrete removal along the reinforcement to where it is well bonded to sound concrete. Clean all corroded reinforcing bars to remain within the concrete removal boundaries by sandblasting or by other suitable methods approved by the Engineer to remove all rust. For bars that have lost ¼ or more of their original diameter , supplement these with new bars spliced in place. Lap new bars (30 diameters on both sides of the affected area) to develop the required full strength of the bar. Additional concrete removal may be necessary to provide this lap. Dual bars of equivalent or greater cross-sectional area may be used. Maintain required concrete cover. Ensure that all newly exposed concrete repair surfaces are free of loose particles and other foreign material . Clean t he repair areas and roughen the areas by the use of sandblasting, compressed air, air and water blasting, steam, wire brushing, or other methods approved by the Engineer in writing. The Contractor may use one or any combination of the various options for cleaning the repair areas as directed by the Engineer. Once all deteriorated concrete has been removed, maintain the existing sound concrete in a clean, rough, and surface saturated moist condition until the concrete repair has been completed.
Part 800 — Bridge Structures August 2025
SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY 800-109 When an epoxy -resin agent is specified, ensure that the prepared sound concrete surface is thoroughly dried before applying the epoxy-resin. During the removal of the designated portions of the structure, avoid damaging the portions that will remain in place. If the removal operation causes excessive damage to portions of the concrete that will remain, cease operations and submit a proposed alternative removal method for approval. Ensure that no debris or any other material falls onto the roadway or waterway below the bridge. Should debris or material fall onto the roadway or waterway, remove the material immediately and cease all work until a revised procedure of operation has been submitted and approved by the Engineer in writing. The Contractor shall be responsible for all damages or injuries as a result of debris or material falling. Do not store or bury material or debris on site. Keep the surface against which mortar will be placed wet for at least one hour and allow the surface to dry to a saturated surface dry (SSD) condition just before application of the repair material. Where bonding agents are specified for use, appl y the agents according to the manufacturer’s recommendations. If practical, ensure that the contact time is not exceeded. If the Contact time is exceeded, reapply the bonding agent . Reapplication, including form removal and re - installation, will be at no additional cost to the Department. Use forms for Portland cement concrete repairs when necessary to confine the concrete and shape it to the required lines. The forms may partially require progressive installation as the concrete is placed as a result of confinements for placing concrete due to the location of the particular repair or restoration required. Ensure that the forms have sufficient strength to withstand the pressure resulting from placing operations, is maintained rigidly in position, and is sufficiently tight to prevent loss o f mortar from the concrete. Do not use form oils. Use an alternative method or material for facilitating form release that will not cause discoloration or staining of the concrete. All methods or materials are subject to the approval of the Engineer. With respect to temperature and weather conditions, use concrete repair materials according to Subsections 601.03.4, 601.03.5, and 601.03.6. Placement of Reinforcing. Repairs less than 1½-in. depth do not require wire mesh reinforcement unless otherwise directed by the Engineer. Where the thickness of the repair mortar exceeds 1½-in. depth and existing bar reinforcement is available, attach galvanized wire mesh reinforcement to the bars with tie wire. If existing rebar is not available, install wire mesh reinforcement using mechanical concrete anchors according to the requirements of the Table below. Where the repair exceeds a 4-in. depth, use a single layer of wire mesh to reinforce each 1-in. thickness of patch material.
Part 800 — Bridge Structures August 2025
800-110 SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY Size and Spacing of Anchors Thickness of Placement (in.) Overhead Surfaces Diameter (in.) Spacing (in.) Vertical Surfaces Diameter (in.) Spacing (in.) Top Horizontal Surface Dia. (in.) Spacing (in.) 1½ to 4 ¼ at 24 ¼ at 24 ¼ at 36 4 to 5 ¼ at 20 ¼ at 24 ¼ at 36 5 to 6 ⅜ at 17 ⅜ at 21 ⅜ at 36 over 6 ⅜ at 16 ⅜ at 20 ⅜ at 36 Use mechanical concrete anchors that are galvanized and hooked-type expansion bolts in drilled holes. Use bolts with sufficient engagement in sound masonry to resist a pull out force of 150 lb. Ensure that the exposed end of each anchor has at a minimum a right-angle bend for engaging reinforcement. Use at least three anchors in each individual patch area. Application of Pneumatically Applied Mortar (Shotcrete).
a.Submittals. Provide S hop Drawings, details, material Certificates of Compliance (including mill test reports), mix designs, Quality Control (QC) Plan to include construction procedures, detailed construction sequencing plans, and details of temporary debris shields. Submit submittals for review and approval by the Engineer a minimum of 45 days before the commencement of work. Ensure that the QC Plan includes the following: ● Number and qualifications of personnel involved in shotcrete placement ● Surface preparation method ● Equipment and materials for placement, finishing, and curing ● Placement method including application rates, plans for multiple layers where applicable, and methods for achieving required thickness and finish ● Curing method ● QC testing and inspection personnel ● QC testing and inspection methods and frequencies including determinations of thickness and strength of placed shotcrete and checking for hollow areas and surface defects ● Methods for correcting deficiencies in shotcrete thickness, strength, hollow areas, and surface defects ● Documentation of nozzle operator’s experience Before new personnel can start work, ensure that shotcreting nozzle operators have at least one year of experience in the application of shotcrete and have completed at least
Part 800 — Bridge Structures August 2025
SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY 800-111 three projects of comparable nature or work under the immediate supervision of a foreman or instructor with at least two years of such experience. Do not begin work until the QC Plan has been approved by the Engineer.
b.Batching and Mixing. Aggregate and cement may be batched by weight or by volume . Ensure that the m ixing equipment can thoroughly mix the materials in sufficient quantity to maintain placing continuity. Ensure that ready mix shotcrete complies with SECTION 601.
c.A pplication Equipment. Apply the shotcrete by pneumatic equipment that sprays the mix onto the prepared surface at the velocity needed to produce a compacted, dense, homogeneous mass. Ensure that t he velocity of the material as it leaves the nozzle maintains a uniform rate determined for the given job conditions to minimize rebound. ● Dry Mix Process. Ensure that the delivery equipment delivers a continuous, smooth, uniformly mixed material to the nozzle. Equip the nozzle with a water ring and valve to permit adjustment of the water. Ensure that the nozzle can deliver a conical discharge stream. ● Wet Mix Process. Only use pneumatic-feed type delivery equipment.
d.Preconstruction Testing. Make test panels for each application crew using the equipment, materials, mixture proportions , and procedures proposed for the job before the commencement of the work. Make a test panel at least 30 in. × 30 in. for each mixture being considered and for each shooting position to be encountered in the job. Fabricate the test panels to the same thickness as in the structure but not less than 4 in. Take at least five, 3-in. minimum diameter cores from each panel for testing according to ASTM C1604. Obtain samples for testing in the presence of the Engineer, which will be tested by the Engineer.
e.P lacement of Shotcrete. Apply shotcrete with the same equipment and the same technique as used to construct the approved test panels. Ensure that the nozzle operator constructing the test panels is the same operator used in placing shotcrete in the work . Apply the shotcrete as dry as practical to prevent shrinkage cracking, sagging, and sloughing off. Use shooting guide strips or wires to ensure square corners, straight lines , and a plane surface of mortar. Place the strips or wires to minimize trapping of rebound. Do not re - use rebounded materials. Install thickness measuring pins on 5-ft centers in all direction. Ensure that t he pins are non-corrosive. The Engineer may approve other methods to establish if the required minimum thickness of shotcrete is being applied if the Contractor can satisfactorily demonstrate the reliability of the other methods. Apply a sufficient number of mortar coats to obtain the required thickness. On vertical and overhead surfaces, ensure that the thickness of each coat is not greater than 1 in., and is placed so that it will neither sag nor decrease the bond of the preceding coat. Ensure that the time interval between successive layers in sloping, vertical or overhanging work, is sufficient to allow initial set but not final set to develop. At the time initial set is developing, clean the surface to remove the thin film of laitance to provide a bond with succeeding
Part 800 — Bridge Structures August 2025
800-112 SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY applications. Remove and dispose of all r ebound or accumulated loose sand from the surface by brooming or scraping. Cover the surface before placing the original or succeeding layers of mortar and ensure that the mortar is not embedded in the work . Remove all laitance that has been allowed to take final set by sandblasting and thoroughly clean the surfaces without damaging the concrete. Ensure an SSD condition exists before shooting new material. Position and secure the wire fabric reinforcement to minimize vibration while the shotcrete is being applied. Lap mesh one and a half squares in both directions. Bend tie wires flat in the plane of the mesh and ensure there are no large knots. Place reinforcement to ensure that proper cover is maintained. Apply the shotcrete to prevent accumulation of rebound on the surface still to be covered. Fill first the horizontal and vertical corners and any area where rebound cannot escape or be blown free. Hold the nozzle at a distance and angle to place material behind the reinforcement before material is allowed to accumulate on its face. Do not place shotcrete through more than one layer of reinforcing steel in one application. Unless suitable means to screen the nozzle is provided, discontinue shotcreting if wind or air currents will cause separation of the stream during placement. Conduct hammer sounding in the presence of the Engineer after sufficient strength is obtained to prevent damage. Hollow areas and areas containing any other non - conforming work or defects are considered deficient areas . Use a n approved repair method, including proposed mitigation measures, to correct deficient areas. Submit the repair method for review and approval by the Engineer in writing before commencement of any repair work . At the discretion of the Engineer, repair deficient areas after initial placement of the shotcrete is completed. Remove and replace with fresh shotcrete all shotcrete defects, including lack of uniformity, segregation, honeycombing, lamination, or the presence of any dry patches, slugs, voids, or sand pockets, all at no additional cost to the Department.
f.Acceptance Testing. Prepare a minimum of one test panel for each day of production up to 50 cu yd and one test panel for each additional increment up to 50 cu yd of shotcrete placed. Ensure that t est panels have minimum dimensions of 24″ × 24″ × 4″ gunned in the same position as the work represented. Ensure that the panels are gunned during the course of the work by the previously qualified nozzle operator. Cure the panels and obtain a minimum of three cores as described under Preconstruction Testing in Para. d above. Cores will be tested by the Engineer according to the requirements under Preconstruction Testing.
g.L imitation of Mixing . Place shotcrete according to the temperature and weather conditions in SECTION 601.
h.F inish . Finish all exposed surfaces straight and true, approximating the original contour as close as practical as indicated on the Plans.
i.Cu ring . Ensure that shotcrete is cured according to SECTION 601.
Part 800 — Bridge Structures August 2025
SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY 800-113 Do not use curing compounds on any surfaces against which additional shotcrete or other cementitious finishing materials will be bonded. Application of Form and Cast-in-Place Concrete.
a.General. Perform repairs accomplished by the form and cast-in-place method according to SECTION 808.
b.U se of Self Consolidating Concrete (SCC) in Form and Cast -in-Place Concrete. Refer to SECTION 601.
c.Fi nal Finish. Finish all exposed surfaces straight and true, approximating the original contour as close as practical as indicated on the Plans. Application of Integrally Colored Concrete or Patching Mortar. Mix, apply, and cure concrete patching mortar according to the manufacturer’s recommendations.
a.Prime Coat. Before placing the concrete or mortar on a previously prepared and approved concrete surface, apply a prime coat to the entire area to be patched using a Portland cement bonding grout slurry. Ensure that the consistency of the Portland cement bonding grout slurry can be applied with a brush on a prepared moist concrete surface in a thin (approximately ⅛ -in.) even coating that will not run or puddle. Do not allow any excess bonding grout to collect in pockets. Apply Portland cement bonding grout to the concrete and the surfaces of the reinforcing bars and into the spaces between the reinforcing bars and the prepared concrete surfaces. Ensure that all surfaces receive a thorough, even coating. Limit the rate of bonding grout application to that surface area that can be covered with new concrete or mortar before the bonding grout begins to dry out. Do not incorporate into the work any grout that has dried or become unworkable, as determined by t he Engineer. If drying does occur, remove the bonding grout and place new bonding grout. The Engineer must approve the removal of the bonding grout method.
b.Placing and Consolidation. Place, consolidate, and finish the integrally colored Portland cement concrete on a previously prepared surface for which a Portland cement bonding grout slurry has been applied. Place integrally colored patching mortar in ½ -in. to 1-in. lift layers within 5 to 10 minutes after water is added to avoid the rapid setup of the material after the application of the bonding grout slurry. If more than one lift layer is required to perform the repair, do not allow the previously placed lift layer to dry, and roughen its surface before placing the next layer. Do not apply patching mortar when the ambient temperature is below 45°F or is not according to the manufacturer’s recommendations.
Part 800 — Bridge Structures August 2025
800-114 SECTION 817 — REPAIRS TO STRUCTURE CONCRETE MASONRY
c.Finish. Use an experienced mason to finish all exposed surfaces straight and true, approximating the original contour as close as practical. Ensure that the final finished surfaces match the texture, color, and aggregate exposure of the existing concrete surfaces adjoining or proximate to the area where new concrete has been placed. Capture all waste and water from the finishing operations, and dispose these materials.
d.Curing. Use curing procedures and methods that comply with the color additive from the manufacturer’s recommendations and as set forth in Subsection 601.03. 7. Do not use curing compounds unless specifically required by the manufacturer of the color additive.
817.04 Method of Measurement.
Repairs to Structure Concrete Masonry – Pneumatically Applied Mortar, Repairs to Structure Concrete Masonry – Patching Mortar, Repairs to Structure Concrete Masonry – Form and Cast- in-Place Concrete, and Repairs to Structural Concrete Masonry with Integrally Colored Concrete or Patching Mortar will be measured by the number of cubic feet of new concrete placed.
817.05 Basis of Payment.
The Department will pay for the completed and accepted quantities as follows. Pay Item Pay Unit Repairs to Structure Concrete Masonry - Pneumatically Applied Mortar CF Repairs to Structure Concrete Masonry - Patching Mortar CF Repairs to Structure Concrete Masonry - Form and Cast-in- Place Concrete CF Repairs to Structural Concrete Masonry with Integrally Colored Concrete or Patching Mortar CF The prices constitute full compensation for all labor, materials, equipment, and incidentals required to finish the work, complete and accepted. Unless called out otherwise in the Plans, steel reinforcing bars and wire mesh reinforcement will be paid for separately by Force Account according to Subsection 109.04 or, when applicable, will be paid under the respective pay item for Reinforcing Steel in SECTION 810. All materials and/or labor costs resulting from the surface finishing operations, including sedimentation and dewatering controls, will be included in this item of work.
Referenced in this section
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Source: Standard Specifications for Road and Bridge Construction (Blue Book), 2022 (Aug 2025 compilation) Edition. Pages 475–483 of 951. View official source ↗