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HomeMy WebLinkAbout72SECTION 03300 (CONTINUED) CAST -IN-PLACE CONCRETE 3.09 CONCRETE PLACEMENT A. Inspection: Before placing concrete, inspect and complete installation of formwork, reinforcing steel, embedded or cast in items. Notify other crafts to permit installation of their work; cooperate with other trades in setting such work. B. General: Comply with ACI 304, "Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete," and as herein specified. C. Deposit concrete continuously or in layers of such thickness that no concrete is placed on concrete that has hardened sufficiently to cause the formation of seams or planes of weakness. If a section cannot be placed continuously, provide construction joints as herein specified. Deposit concrete to avoid segregation at its final location. D. Placing Concrete in Forms: Deposit concrete in forms in horizontal layers not deeper than 24 inches and in a manner to avoid inclined construction joints. Where placement consists of several layers, place each layer while preceding layer is still plastic to avoid cold joints. 1. Consolidate concrete by mechanical vibrating equipment supplemented by hand spading, rodding, or tamping. Use equipment and procedures for consolidation of concrete in accordance with ACI 309. 2. Do not use vibrators to transport concrete inside forms. Insert and withdraw vibrators vertically at uniformly spaced locations not farther than visible effectiveness of machine. Place vibrators to rapidly penetrate placed layer and at least 6 inches into preceding layer. Do not insert vibrators into lower layers of concrete that have begun to set. At each insertion limit duration of vibration to time necessary to consolidate concrete and complete embedment of reinforcement and other embedded items without causing segregation of mix. E. Placing concrete slabs on grade: Deposit and consolidate concrete slabs in a continuous operation, within limits of construction joints, until the placing of a panel or section is completed. 1. Use of laser screeds for slabs on grade is mandatory. 2. Consolidate concrete during placing operations so that concrete is thoroughly worked around reinforcement and other embedded items and into corners. 3. Use straightedge to smooth and straighten the surface. Do not disturb slab surfaces prior to beginning finishing operations. 4. Maintain reinforcing in proper position during concrete placement. F. Placing Concrete slabs on steel deck: 1. Planking shall be placed where buggies are utilized and under hoses a) Provide protection of metal deck from loads due to equipment b) Contractor placing concrete shall bear all costs for repairs to steel deck due to damage from buggies, hoses or other equipment used to place or finish concrete. 2. Start placing concrete in middle of bay and spread toward supporting beams and girders. Place concrete in a uniform manner. a) Exercise care when placing concrete so that the deck is not subject to impact loads or wet concrete loads that exceed the load carrying capacity of the deck. b) Compensate for deflection of deck and structure to provide level, flat slab while maintaining minimum specified slab thickness. c) Use stick to measure thickness of slab during pours d) Do not use lasers to set top of slab until after measuring thickness with stick. Then only add to thickness to provide a level slab. G. WATER: NO WATER SHALL BE ADDED TO THE CONCRETE ON SITE UNLESS DIRECTED BY SUPERINTENDENT OR TESTING AGENCY REPRESENTATIVE. H. Cold_Weather Placing: Comply with provisions of ACI 306 and as follows. Protect concrete work from physical damage or reduced strength that could be caused by frost, freezing actions, or low temperatures. I. When air temperature has fallen to or is expected to fall below 40 deg F (4 deg C), uniformly heat water and aggregates before mixing to obtain a concrete mixture temperature of not less than 50 deg F (10 deg C) and not more than 80 deg F (27 deg C) at point of placement. 1. Do not use frozen materials or materials containing ice or snow. Do not place concrete on frozen subgrade or on subgrade containing frozen materials. 2. Do not use antifreeze agents or chemical accelerators containing calcium chloride or chloride bearing salts. Other antifreeze agents or chemical accelerators may be used if acceptable to engineer. J. Hot Weather Placing: When hot weather conditions exist that would seriously impair quality and strength of concrete, place concrete in compliance with ACI 305 and as herein specified. 1. Cool ingredients before mixing to maintain concrete temperature at time of placement below 90 deg F (32 deg C). Mixing water may be chilled, or chopped ice may be used to control temperature provided water equivalent of ice is calculated to total amount of mixing water. Use of liquid nitrogen to cool concrete is sub -contractor's option. 2. Cover reinforcing steel with water -soaked burlap if it becomes too hot, so that steel temperature will not exceed the ambient air temperature immediately before embedment in concrete. 3. Fog spray forms, reinforcing steel and subgrade just before placement of concrete. 4. Use water -reducing, retarding admixture when required by high temperatures, low humidity, or other adverse placing conditions, when acceptable to Engineer. K. Placement Tolerances 1. The centerline of column footings must within four inches of the location shown on the design drawings. Footing that are located outside of this tolerance shall be removed and replaced at no cost to owner. 3.10 FINISH OF FORMED SURFACES A. Rough Form Finish: For formed concrete surfaces not exposed to view in the finish work or concealed by other construction. This is the concrete surface having texture imparted by form -facing material. Repair defective areas and remove fins and other projections exceeding 1/4 inch in height by rubbing down or chipping off. B. Smooth Form Finish: For formed concrete surfaces exposed to view or to be covered with a coating material applied directly to concrete, or a covering material applied directly to concrete, such as waterproofing, damp proofing, veneer plaster, painting, or other similar system. This is an as -cost concrete surface obtained with selected form -facing material, arranged in an orderly and symmetrical manner with a minimum of seams. Repair and patch defective areas with fins and other projections completely removed and smoothed. C. Related Unformed Surfaces At tops of walls, horizontal offsets, and similar unformed surfaces occurring adjacent to formed surfaces, st(ke-off smooth and finish with a texture matching adjacent formed surfaces. Continue final surface treatment of formed surfaces uniformly across adjacent unformed surfaces unless otherwise indicated. 3.11 MONOLITHIC SLAB FINISHES A. Float Finish: Apply float finish to monolithic slab surfaces to receive trowel finish and other finishes as hereinafter specified; slab surfaces to be covered with membrane or elastic waterproofing, membrane or elastic roofing, and as otherwise indicated. B. Trowel Finish: Apply trowel finish to monolithic slab surfaces to be exposed to view and slab surfaces to be covered with resilient flooring, carpet, ceramic or quarry tile, paint, or other thin film finish coating system. 1. After floating, begin first trowel finish operation using a power -driven trowel. Begin final troweling when surface produces a ringing sound as trowel moves over surface. Consolidate concrete surface by final hand -troweling operation, free of trowel marks, and uniform in texture and appearance. Grind smooth surface defects that would telegraph through applied floor covering system. a) Slab -on -Grades: 1. Use blades for first machine troweling operations. Do not use pans. 2. Pans may be used on subsequent operations C. Non -slip Broom Finish: Apply non -slip broom finish to exterior concrete platforms, steps, and ramps, and elsewhere as indicated. 1. Immediately after float finishing, slightly roughen concrete surface by brooming with fiber -bristle broom perpendicular to main traffic route. Coordinate required final finish with Architect. 3.12 FLATNESS AND LEVELNESS: A. The elevation of the top of slabs -on -grades shall be within %" of the top of slab elevations specified on the contract (civil) documents. B. The elevation of the top of slabs -on -decks shall be within %* of the top of slab elevations specified on the contract documents. For un -shored systems, elevations shall be measured at each column. C. The entire slab -on -grade is designated as a random traffic floor. The slab -on -metal deck is designated as a separate random traffic floor. 1. The "Local Floor Section" shall be each and every bay defined by column grid lines D. Finish surfaces to flatness and levelness tolerances spec`fied below and as measured according to ASTM E1155. Grind smooth high spots and surface defects that would telegraph through applied floor covering systems. 1. Random traffic areas as noted below. Flatness and levelness numbers shown on plan shall take precedent over the following values. a) Specified overall values (SOV) FF=35 FL=25 1. The SOV applies to each "designated random traffic floor", not each placement b) Minimum local values (MLV) FF=25 FL=20 1. The MLV applies to each "local floor section" 2. Floor slabs on metal deck shall meet the following requirements: a) Specified overall value FF =25 1. The SOV applies to eacn "designated random traffic floor", not each placement b) Minimum local value FF=20 1. The MLV applies to each "local floor section" c) FL numbers do not apply to slabs placed on un -shored form surfaces nor formed surfaces after removal of forms 3. At construction joints, a 10 -foot straight edge centered )n the construction joint shall not have a gap of more than 1/8 inch ut center (joint too low) or either end (joint too high). 3.13 CONCRETE CURING AND PROTECTION A. General: Protect freshly placed concrete from premature drying and excessive cold or hot temperatures. In hot, dry, or windy weather, protect concrete from rapid moisture loss before and during finishing operations. B. Curing Methods: Perform curing of concrete by curing and sealing compound (sprayed on liquid membrane) or other methods approved. C. Apply curing and sealing compound to interior and exterior slabs, walks, and curbs as follows: 1. Apply specified curing and sealing compound to concrete slabs as soon as final finishing operations are complete (within 2 hours and after surface water sheen has disappeared). Apply uniformly in continuous operation by power spray ..r roller in accordance with manufacturer's directions. Recoat areas subjected to heavy rainfall within 3 hours after initial application. Maintain continuity of coating and repair damage during curing period. 2. Representative from manufacturer must be on site during application of Ashford Formula. D. Curing Unformed Surfaces: Cure unformed surfaces, such as slabs, floor topping, and other flat surfaces, by application of appropriate curing method. 3.14 REMOVAL OF FORMS A. General: Do not remove formwork until concrete has attained sufficient strength to support its own weight and not sustain damage by formwork removal. 3.15 REUSE OF FORMS A. Clean and repair surfaces of forms to be reused in work. Split, frayed, delaminated, or otherwise damaged form -facing material will not be acceptable for exposed surfaces. Apply new form -coating compound as specified for new formwork. B. When forms are extended for successive concrete placement, thoroughly clean surfaces, remove fins and laitance, and tighten forms to close joints. Align and secure joint to avoid offsets. Do not use "patched" forms for exposed concrete surfaces except as acceptable to Architect. 3.16 MISCELLANEOUS CONCRETE ITEMS A. Filling In: Fill in holes and openings left in concrete structures for passage of work by other trades, unless otherwise shown or directed, after work of other trades is in place. Mix, place, and cure concrete as Provide other miscelk,neous concrete fillip herein specified, to blend with in-place construction. o g shown or required to complete work. B. Curbs and Ramps: Provide monolithic finish to interior curbs and ramps (where required) by stripping forms while concrete is still green and steel -troweling surfaces to a hard, dense finish with comers, intersections, and terminations slightly rounded. C. Equipment Bases and Foundations: Provide machine and equipment bases and foundations, as shown on drawings. Set anchor bolts for machines and equipment to template at correct elevations, complying with certified diagrams or templates of manufacturer furnishing machines and equipment. D. Steel Pan Stairs: Provide concrete fill for treads of steel pan stairs and. landings and associated items. Cast -in safety inserts and accessories as shown on d7awings. Screed, tamp and finish concrete surfaces. 3.17 CONCRETE SURFACE REPAIRS A. Patching Defective Areas: Repair and patch defective areas with cement mortar immediately after removal of forms, when acceptable to Architect. 1. Cut out honeycomb, rock pockets, voids, and holes left by tie rods and bolts, down to solid concrete. Make edges of cuts perpendicular to the concrete surface. Thoroughly clean, dampen with water, and brush -coat the area to be patched with specified bording agent. Place patching mortar before bonding compound has dried. 2. For exposed -to -view surfaces, blend white Portland cement and standard Portland cement so that, when dry, pafching mortar will match color surrounding. Provide test areas at inconspicuous location to verify mixture and color match before proceeding with patching. Compact mortar in place and strike -off slightly higher than surrounding surface. B. Repair of Formed Surfaces: Remove and replace concrete having defective surfaces if defects cannot be repaired to satisfaction of Engineer. Surface defects, as such, include color and texture irregularities, cracks, spalls, air bubbles, honeycomb, rock pockets, fins and other projections on surface, and stains and other d:scolorations that cannot be removed by cleaning. Flush out form tie holes, fill with dry -pack mortar, or precast cement cone plugs secured in place with bonding agent. C. Repair of Unformed Surfaces: Test unformed surfaces, such as monolithic slabs, for smoothness and verify surface plane to tolerances specified for each surface and finish. Correct low and high areas as herein specified. Test unformed sp!rfaces sloped to drain for trueness of slope and smoothness by using a template having required slope. 1. General: a) Repair finished unformed surfaces that contain defects that affect durability of concrete. Surface defects, as such, include crazing and cracks in excess of 0.01 inch wide or that penetrate to reinforcement or completely through unreinforcea sections regardless of width, spilling, popouts, honeycomb, rock pockets, and other objectionable conditions. 2. Slabs -on -grade in random traffic areas: a) Local Floor Sections (as defined above) where the "combined section" numbers do not meet the minimum local value: 1. Remove and replace the Local Floor Section. 2. Grinding high spots may bring the slab into tolerance in one direction but may also take it out of tolerance in the other direction. Therefore grinding should only be used when there is an obvious defect in a limited area. 3. Filling low spots is acceptable in areas not exposed to weather and to receive a floor covering. 4. Filling is NEVER allowed in areas to receive any kind of vehicular traffic b) Slabs that do not meet the Specified Overall Values but the "Combined Section" numbers DO meet the minimum local value in all sections: 1. No remedial work is required to correct the slab. However, the concrete Cnisher did not provide a slab that conforms to the project specifications. Therefcre the contractor shall rebate to the owner an amount equal to the slab area x $0.50 per square foot. 3.Other unformed surfaces: a) Repair finished unformed surfaces that contain defects that affect durability of concrete. Surface defects, as such, include crazing and cracks in excess of 0.01 inch wide or that penetrate to reinforcement or completely through unreinfomed sections regardless of width, spilling, popouts, honeycomb, rock pockets, and other objectionable conditions. b) Correct high areas by grinding after concrete has cured at least 14 days. c) Correct low areas in unformed surfaces during or immediately after completion of surface finishing operations by cutting out low areas and replacing with patching compound. Finish repaired areas to blend into adjacent concrete. 1. Filling in low areas with concrete, cement, repair mortar of similar material is not allowed. d) Repair defective areas, except random cracks and single holes not exceeding 1 inch in diameter, by cutting out and replacing with fresh concrete. Remove defective areas to sound concrete with clean, square cuts and expose reinforcing steel with at least 3/4 -inch clearance all around. Dampen concrete surfaces in contact with patching concrete and apply bonding compound. Mix patching concrete of same materials to provide concrete of same type or class as original concrete. Place, compact, and finish blending with adjacent finished concrete. Cure in same manner as adjacent concrete. D. Repair methods not spechied above are subject to approval b; i.he Engineer prior to use. 13 3.18 QUALITY CONTROL TESTING DURING CONSTRUCTION A. General: A material testing laboratory shall be engaged per division 1 to perform tests. B. Sampling and testing for quality control during placement of concrete shall include the following. C. Sampling Fresh Concrete: ASTM C 172, except modified for slump to comply with ASTM C 94. 1. Slump: ASTM C 143; one test at point of placement as follows: a) Foundations & Slabs: One test for each set of compressive or flexural strength specimens. b) "Point of placement" means the discharge end of the hose for pumped concrete. 2. Air Content: ASTM C 173, volumetric method for lightweight or normal weight concrete; ASTM C 231 pressure method for normal weight concrete; one per specimen set of each type of air entrained concrete. 3. Concrete Temperature: Test hourly during duration of pour. 4. Compression Test Specimens: ASTM C 31; one set of four standard cylinders for each compressive strength test, unless otherwise directed. Mold and store cylinders for laboratory -cured test specimens. When temperature is expected to fall below 40o provide additional specimen set for each test set. The additional set shall be field -cured. 5. Compressive Strength Tests: ASTM C 39; one set for each day's pour of appreciable size and for each 100 cu. yds. Test one specimen at 7 days, two specimens at 28 days, and one specimen retained in reserve for later testing if required. a) Note location on test reports 6. When total quantity of a given class of concrete is less than 50 cubic yards, Engineer may waive strength test when provided with adequate evidence of satisfactory strength. 7. Compressive strength of concrete will be considered satisfactory if averages of sets of three consecutive strength test results equal or exceed specified compressive strength, and no individual strength test result falls below specified compressive strength by more than 500 psi. 8. Concrete Yield Test - Minimum one (1) per project - recommend first floor slab pour. D. Concrete Floor Flatness and Levelness 1. Four devices are available for measuring F-numbers. All are acceptable. However, the some type of device shall be used for all measurements on the project. Device must be calibrated within the past three months. 2. Two (2) Layout Patterns Per ASTM Ell 155-87 a)45 degree angles to the longest boundary (x - pattern) 3. Perform the floor flatness and levelness testing as follows: a) Owner's Representative or General Contractor shall determine the square footage of slab to be tested. Test areas should include but not be limited to: 1. Each of the first three slab placements 2. Every other slab placement after the first three placements b) Provide one test section for each "Local Floor Section" of each placement. c) Perform tests within 24 hours after placement of the slab. d) Provide results to project manager and superintendent within 24 hours of each test (final, formal written reports may follow later). e) Test Report: 1. Report shall provide "Combined Section" Ff and FI numbers for each "local floor section". a. "Combined Section" Ff and FI numbers: These are the test results for each separate "Local Floor Section" and are compared to the minimum local values. 2. Final report should list "Project Summary" Ff and A numbers for each "random traffic floor". a. "Project Summary" Ff and A numbers: These are the tests results for one "Random Traffic Floor". The project summary numbers are the area weighted average of all of the "Combined Section" numbers for the specific "Random Traffic Floor". 3. There should not be an "overall average" for each placement. An average for the placement may be provided in the report if listed as "Average for Placement (Not Overall Average)" 4. Testing at constructions joints: a) Check all construction joints with a 10 -foot straight edge centered on the construction joint. Any joint that does not meet with a 1/8 inch or less gap under the straight edge either at the center (joint too low) or at the ends (joint too high -straight edge rocks) will require grinding until the 1/8 inch tolerance is met or the joint is acceptable. Check every ten feet along joints. b) Check the construction joints within 48 hours after placement of the last abutting slab. 5. Any and all areas that fail the Floor Flatness and Levelness tests must be repaired following the requirements of section 3.16 "Concrete Surface Repairs". E. The following areas are excluded from testing for Flatness and levelness using the dipstick or wheel. a) Areas within ten feet of : 1. Construction or control joints 2. Pipes or similar objects protruding out of the slab 3. Dock leveler pits, pits for scales 4. Floor drains or trench drains 5. Elevator pits b) Stair landings and treads F. Report test in writing to General contractor, Structural Engineer, Ready -Mix Producer, and subcontractor within 24 hours of testing. Reports of tests shall contain the project identification name and number, date of concrete placement, name of concrete testing service, concrete type and class, location of concrete batch in structure, specified strength at 28 days, concrete mix proportions and materials, compressive breaking strength, and type of break for both 7 day tests and 28 day tests. G. Nondestructive Testing: Impact hammer, sonoscope, or other nondestructive device may be permitted but shall not be used as the sole basis for acceptance or rejection. END OF SECTION �j p�55�Zw�e 00 Uwij�fw��o�� a�wy€y Sbo c°�p B�wS0�r!1 plcg w .�j Z UaO�Z Ow mrL F_ S6 2. WH_ �Wr{W Sr.mz4JT203C 2 Z,2 �fignl p3zrcUF N a�a�;� 10 WZW Z Q 0 Z O LL" w J Z U U Lai >11111110of LLJ > J W � 0 J 0 J LLJ O Z J Q W Z w V) H rn Q V) t c0 rn D isreq��//�'% 0. _�. 870326 STATE OF ; ���`�l` • �ND I ANP SS/ONA`I_ ❑ ❑ u 00 o ® o ® o C) 0 z z :3 a •> 0 m C cn z Z 0 a it 0 N W in W Y 0 V) 0 m o U W J W V � E Z _ ILIL a P0 N w Z} a P0 s 0 Z 0 U) N w � Z a4 Y Q a o � cc �c © 2013 PROFESSIONAL ENGINEERS' GROUP, INC. STRUCTURAL SPECIFICATIONS S402