622.01 664 SECTION 622 – SHOTCRETE
622.01 Description ................................ ................................ ................... 664
622.02 Materials ................................ ................................ ...................... 664
622.03 Propor tioning and Quality Assurance of Shotcrete ...................... 664
622.04 Preconstruction Test Panels ................................ ......................... 667
622.05 Production Test Panels ................................ ................................ . 668
622.06 Test Panel Curing and Testing ................................ ..................... 668
622.07 Mixing and Batching Shotcrete ................................ .................... 669
622.08 Equipment ................................ ................................ .................... 669
622.09 Method of Measurement ................................ .............................. 669
622.10 Basis of Payment ................................ ................................ .......... 670
DESCRIPTION
622.01 Description
This work consists of constructing shotcrete in reasonably close conformance with the Plans or as established by the Engineer. MATERIALS
622.02 Materials
Provide materials as specified in: Portland Cement , Type I ................................ ........................ 901.01 Fine Aggregate ................................ ................................ ....... 903.01 Coarse Aggregate ................................ ................................ .. 903.22 Water ................................ ................................ ...................... 921.01 Fly Ash ................................ ................................ ................... 921.15
622.03 Proportioning and Quality Assurance of Shotcrete
A.Proportioning Submit the proposed shotcrete design to the Engineer for approval. Establish the design using saturated surface dry aggregate weights and 622.03 665 trial batches meeting the specified performance requirements. Make all strength determinations on equipment meeting the requirements of and in the manner prescribed by AASHTO T 22. Build t rial batches and preconstruction test panel s no more than 60 days prior to the design submittal. Assume responsibility for all costs related to concrete design, preparation, and submittal. Include the following, as a minimum, in the proposed shotcrete design submittal:
1.Source of all aggregates
2.Brand and type of cement
3.Source and class of fly ash (if used)
4.Specific gravity of cement
5.Specific gravity of fly ash (if used)
6.Admixtures (if used)
7.Gradations of aggregates
8.Specific gravity of aggregates (saturated surface dry)
9.Percentage of fine aggregate of total aggregate (by volume)
10.Water-cement ratio (w/c)
11.Weights of each material required to produce a cubic yard of concrete
12.3-day compressive strength ( three 3-inch diameter cores taken from test panel or wall face)
13.28-day compressive strength ( three 3-inch diameter cores taken from test panel or wall face)
14.7-day absorption (three 3 -inch diameter cores taken from test panel or wall face) Shotcrete shall meet the perform ance requirements specified in Table
622.03 1.
622.03 666 Table 622.03-1: Shotcrete Performance Requirements Parameter Value 3-Day Compressive Strength (psi) 2000 28-Day Compressive Strength (psi) 4000 Minimum Cementitious per cubic yard 660 Maximum Water/Cement (pound/pound) 0.45 Air Content (%) 7-10 (1) 7-Day Maximum Absorption (%) 8
1.Air content acceptance range shall be between 7 -10%, with sampling at the truck chute. Air entrainment is required for wet -mix shotcrete but not for dry-mix shotcrete. Aggregate for shotcrete shall meet the strength and durability requirements of AASHTO M 6/M 80 and the gradation requirements specified in Table 622.03 -2. An intermediate size aggregate may also be used as an additional component if ne eded to meet gradation. Aggregates failing to comply with Table 622.03 -2 may be used if preconstruction testing as specified in 622.04 proves satisfactory results. Table 622.03-2: Gradation Requirements Sieve Size Percent Passing by Weight ¾ inch 100 ½ inch 98-100 3/8 inch 90-100 No. 4 70-85 No. 8 50-70 No. 16 35-60 No. 30 20-50 No. 50 8-20 No. 100 0-10 Chemical admixtures to be incorporated into the shotcrete shall be compatible and incorporated into the concrete in accordance with the manufacturer’s recommendations. Concrete mixtures utilizing multiple 622.04 667 admixture manufacturers shall prove compatibility in accordance with Departmental procedures . Ensure that accelerators (if used) are compatible with the cement used, are non -corrosive t o steel, and will not promote other detrimental effects such as cracking and excessive shrinkage.
B.Quality Control and Acceptance of Shotcrete It is the Contractor’s responsibility to determine and measure th e batch quantities of all ingredients (including all water and specified or approved admixtures) for all shotcrete so that the shotcrete meets the specified requirements. During all batching operations , provide at the concrete plant a TDOT Concrete Plant Quality Control Technician, who shall have the primary responsibility of process control, including all sampling, testing , and inspection of the aggregate and shotcrete. The average compressive strength of each set of three test cores extracted from test p anels or wall facing shall equal or exceed 85% of the specified compressive strength, with no individual core less than 75% of the specified compressive strength, as determined according to ACI 506.2. Do not take cores from the outer 6 inches of test pane ls, measured in from the top outside edges of the panel form. Trim the ends of compressive strength cores to provide test cylinders that are at least 3 inches long. Do not trim ends for absorption cores. Provide all equipment, materials, and personnel necessary to obtain shotcrete cores for testing, including constructing test panel boxes, field curing, and coring. The Engineer will perform c ompressive strength and boiled absorption testing and will base s hotcrete final acceptance on 28-day compressive strength.
C.Placement of Shotcrete An ACI-certified Shotcrete Nozzleman shall be utilized to properly place shotcrete.
622.04 Preconstruction Test Panels
Furnish two preconstruction test panels for each proposed mixture being considered and for each shooting position to be encountered on the Project. Make preconstruction test panels prior to production and as part of the mix design submittal process , using the same equipment, materials, mixture, proportions, and procedures proposed for the work. 622.05 668 Construct the preconstruction test panels with minimum dimensions of 30 x 30 inches square and at least 4 inches thick. Slope the sides at 45 degrees over t he full panel thickness of release rebound. Construct one preconstruction test panel to include the maximum anticipated reinforcing congestion shown on the Plans. Cores extracted from the test panel shall demonstrate encapsulation of the reinforcement i n accordance with ACI 506.2 equal to core Grade 2 or better. Construct the second preconstruction test panel without reinforcement and extract nine 3 -inch diameter cores for absorption and compressive strength testing.
622.05 Production Test Panels
Provide nine 3 -inch diameter cores from a minimum of one production test panel or, instead of production test panels, taken from the shotcrete facing during the first production application of shotcrete and henceforth for every 5,000 square feet of shotcrete placed. Cut at least nine 3-inch diameter core samples from each production test panel for absorption and compressive strength testing. If choosing to take cores from the wall face instead of making production t est panels, take cores at the locations designated by the Engineer. Fill core holes in the wall facing by dry packing with non -shrink patching mortar after cleaning and dampening the holes. Do not fill core holes with shotcrete. Construct p roduction test panels simultaneously with the shotcrete facing installation at times designated by the Engineer. Production test panels shall be a minimum full thickness of 18 x 18 inches square and at least 4 inches thick. The Contractor may extract test specimens f rom test pan els in the field or may transport them to another location for extraction. Keep panels in their forms during transport .
622.06 Test Panel Curing and Testing
Immediately after shooting the test panels, field moist cure the panels by covering and tightly wrapping with a sheet of material meeting ASTM C171 until they are delivered to the testing lab or test specimens are extracted. Do not immerse test panels in water. Do not further disturb test panels for the first 24 hours after shooting. 622.07 669 Clearly mark preconstruction/production cores and containers to identify core locations. If for production testing, mark the section of the wall represented by the cores o n the cores and container. Immediately wrap cores in wet burlap or material meeting ASTM C171, and seal in a plastic bag. Deliver cores to the Engineer or testing lab, as directed by the Engineer, within 48 hours of shooting the panels. When the test le ngth of a core is less than twice the diameter, the correction factors given in AASHTO T 24 will be applied to obtain the compressive strength of individual cores. The remainders of the panels shall become the property of the Contractor.
622.07 Mixing an d Batching Shotcrete
Aggregate and cement may be batched by weight or by volume in accordance with AASHTO M 241 (ASTM C685). Ready mix shotcrete shall comply with AASHTO M 157. Batch, deliver, and place shotcrete within 90 minutes of mixing. The use of retarding admixtures may extend application time beyond 90 minutes if approved by the Engineer. Premixed and packaged shotcrete mix may be provided for on -site mixing. The packages shall contain materials conforming to 622.02 and be from a source on the Department’s Producer List . Place the material within the time limit following mixing recommended by the manufacturer. EQUIPMENT
622.08 Equipment
Use mixing equipment that thoroughly blends the materials in sufficient quality to maintain placing continuity. COMPENSATION
622.09 Method of Measurement
The Department will measure completed and accepted quantities of shotcrete in square feet, by taking measurements over and parallel to the actual area of the applied shotcrete. 622.10 670 622.10 Basis of Payment The Department will pay for accepted quantities at the contract prices as follows: Item Pay Unit Shotcrete Square Feet Such payment is full compensation for furnishing all labor, materials, tools, equipment, and incident als required to place the shotcrete, including surface preparation. 623.01 671 SECTION 623 – BRIDGE EXPANSION JOINTS
623.01 Scope of Work ................................ ................................ ............. 671
623.02 Modular Roadway Expansion Joints ................................ ............ 671
623.03 Strip Seal Expansion Joints ................................ .......................... 675
623.04 Method of Measurement ................................ .............................. 678
623.05 Basis of Payment ................................ ................................ .......... 678
DESCRIPTION
623.01 Scope of Work
This work consist s of fabricating and installing shop fabricated bridge expansion joint systems , of the general size, configuration, and joint movement specified.
623.02 Modular Roadway Expansion Joints
This Subsection is applicable to expansion joints having a required movement in excess of 4 inches.
A.Fatigue Design Provide certification that all proposed modular expansion devices have been tested in accordance with the National Research Program Report 467 Performance Testing for Modu lar Bridge Joint Systems .
B.Materials
1.General. All parts and elements shall be of the material and design indicated in the manufacturer’s catalog, except as otherwise specified in the Contract or shown on the Plans.
2.Steel Plates, Bars, Rolled Shapes, and Extrusions. All steel plates, bars, rolled sh apes, and extrusions shall be fabricated from high-strength, low alloy grade 50S, HPS50W steel, conforming to the requirements of ASTM A709 grade 50 or 50W, as shown on approved shop drawings. Anchor bars may be A36 steel. All membrane retainers shall ha ve a 3/8-inch minimum thickness.
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 673–679 of 1,072.