Special Provision No. 904S13 May 2005

Transcription

1 HIGH PERFORMANCE CONCRETE IN SUBSTRUCTURE Item No. HIGH PERFORMANCE CONCRETE IN STRUCTURE Item No. HIGH PERFORMANCE CONCRETE IN APPROACH SLAB - Item No. HIGH PERFORMANCE CONCRETE IN DECK Item No. HIGH PERFORMANCE CONCRETE IN BARRIER WALLS Item No. HIGH PERFORMANCE CONCRETE IN PARAPET WALLS - Item No. HIGH PERFORMANCE CONCRETE IN SUBSTRUCTURE AND RETAINING WALLS - Item No. Special Provision No. 904S13 May 2005 High Performance Concrete OPSS 904, January 1995, is amended as follows: REFERENCES Section of OPSS 904 is amended by the addition of the following: Ontario Provincial Standard Specifications, Construction: OPSS 932 Crack Repair - Concrete American Society for Testing and Materials: ASTM C 457 -Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete ASTM C1202 -Standard Test Method for Electrical Indication of Concrete s Ability to Resist Chloride Ion Penetration Ministry of Transportation, Ontario, Laboratory Testing Manual: LS-100 LS-431 Method for Rounding Off of Test Data and Other Numbers Method of Test for Microscopical Determination of Air Void System Parameters in Hardened Concrete, for Conformance Testing DEFINITIONS Section of OPSS 904 is amended by the addition of the following: High Performance Concrete: means concrete with a minimum specified 28 day compressive strength of at least 50 MPa, which must include silica fume and may include other supplementary cementing materials, having a specified rapid chloride permeability at 28 days of 1000 coulombs or less. Pier: means a substructure unit that supports the spans of a multi-span superstructure at an intermediate location between its abutments. The pier can consist of a number of different elements, for example- columns, pier cap, piles etc. Temperature Difference: means temperature difference between the centre of the concrete component at a location where the concrete is expected to reach the highest temperature, and the surface of the concrete. May 2005 Page 1 of 24 SSP 904S13

2 Segregation: means visible separation of the mortar and coarse aggregate particles in the concrete, resulting in concrete that is not uniform in appearance or proportions. Referee Testing: Additional testing of an attribute(s) for the purpose of resolving material testing issues at the request of the Contractor or the Owner when the contractual conditions for requesting referee testing have been met. Referee testing is carried out by a laboratory independent of the Contractor and Owner designated by the Owner from a Roster Rotation List maintained for this purpose. Referee test results shall be binding on both the Contractor and the Owner SUBMISSION AND DESIGN REQUIREMENTS Mix Design Subsection of OPSS 904 is deleted and replaced by the following: The Contractor shall be responsible for the concrete mix design Submissions Concrete Strength 35 MPa and Greater The clause of OPSS 904 is deleted. Subsection of OPSS 904 is amended by the addition of the following: Temperature Control Plan Five business days prior to the commencement of placing any high performance concrete, details of the Contractor s planned procedures to effectively monitor and control the temperature and temperature difference of high performance concrete components before, during and after placement shall be submitted to the Contract Administrator for information purposes. Details of the temperature control plan shall include as a minimum the following: 1) Specific measures to be taken by the Contractor before, during and after concrete placement to control the temperature and temperature difference within the limits specified in the Contract. The plan shall address: Work schedule, Time of placement, Any modifications to mix design with significant changes requiring submission of new mix design and supporting documentation, Production, Delivery schedule, and Any other specific measures to be taken. 2) Temperature monitoring system including the locations number of thermocouples and frequencies of recordings to be used in each placement to meet the contract requirements. May 2005 Page 2 of 24 SSP 904S13

3 Air Void System Results from Trial Slab When trial slab is required, the Contractor shall submit results of air void system testing obtained on cores extracted from the trial slab to the Contract Administrator within 10 days of the trial slab placement MATERIALS Concrete Subsection of OPSS 904 is deleted and replaced with the following: Concrete shall conform to the requirements of OPSS 1350, January 1995 amended as follows: REFERENCES Section of OPSS 1350 is amended by the addition of the following: Canadian Standards Association Standards: CSA A CSA A /A Cementitious Materials Compendium Concrete Materials and Methods of Concrete Construction/Methods of Test for Concrete American Society for Testing and Materials Standards: ASTM C494 ASTM C1017 Standard Specification for Admixtures Standard Specification for Chemical Admixtures for Use in Producing Flowing Concrete SUBMISSION AND DESIGN REQUIREMENTS Submissions Clause of OPSS 1350 is deleted and replaced with the following: Concrete Mix Data All concrete mix designs shall be submitted to the Contract Administrator as specified elsewhere in the Contract Documents. Subsection of OPSS 1350 is amended by the addition of the following: Material Quality Test Data and Other Information for High Performance Concrete Except for the trial batch mix design, the Contractor shall include documentation with the submission of the mix design which demonstrates that the proposed mix design and materials meet the submission of this Special Provision, including the following: a) Air void system in the hardened concrete, May 2005 Page 3 of 24 SSP 904S13

4 b) 28 day compressive strength, c) Rapid chloride permeability at 28 days. At the same time as the high performance concrete mix design is submitted, the contractor shall also submit: a) A certificate from the manufacturer of the superplasticizer verifying that: the superplasticizer conforms to ASTM C 494 and C 1017 requirements and no chlorides were added to the superplasticizer during its manufacture b) The maximum concrete production rate required for the work. The supporting test data and the certificate shall be not more than 12 months old at the time the concrete mix design is submitted MATERIALS Cementing Materials Clause of OPSS 1350 is deleted and replaced by the following: Cementing materials shall conform to OPSS 1301, and CSA A Blended hydraulic cement, Type GUb-8SF or Type GUb-22S/5SF, shall be used. A portion of the blended cement may be replaced by Portland cement Type GU, ground granulated blast furnace slag or fly ash or a combination of these. The total amount of slag or fly ash present in the mix shall be restricted to the following proportions by mass of the total cementing materials: 1. Slag up to 25%; or 2. Fly ash up to 25%; or 3. A mixture of slag and fly ash up to 25% Water Clause of OPSS 1350 is deleted and replaced with the following: Water Used for Making, Fog Misting and Curing of High Performance Concrete Water used for making, fog misting and curing of high performance concrete including pre-soaking of burlap, shall either be approved as potable water by the Ministry of Health or shall be tested by the Contractor for time of set and compressive strength prior to its use to ensure that it meets the requirements of OPSS Air Entraining and Chemical Admixtures Clause of OPSS 1350 is deleted and replaced with the following: Air entraining and chemical admixtures shall conform to OPSS 1303 with the exception of superplasticizers, which shall conform to ASTM C 494 and ASTM C May 2005 Page 4 of 24 SSP 904S13

5 A superplasticizer shall be used in the high performance concrete. The Contractor shall ensure that the chosen superplasticizer in combination with cementing materials and other admixtures in the concrete mix has slump retention characteristics that allow the concrete to be delivered, placed and finished so that it meets the requirements of this special provision Air Content Clause of OPSS 1350 is deleted and replaced by the following: Air Content Measured in Plastic Concrete Air content of plastic concrete shall be within ± 1.5 % of the target value identified by the Contractor in the mix design Slump Clause of OPSS 1350 is deleted and replaced with the following: Slump shall be measured in conformance with CAN/CSA A23.2-5C. Slumps measured immediately prior to placing or pumping shall be no more than 230 mm. After discharging of a truckload of concrete has started, one redose of the superplasticizer will be allowed Physical Requirements for Concrete Subsection is amended by the addition of the following clauses: Rapid Chloride Permeability Rapid chloride permeability of concrete at 28 days, determined in accordance with ASTM C1202, shall be equal to or less than 1000 coulombs Air Void System Air void system parameters as determined on the hardened concrete in accordance with ASTM C 457 shall meet the following requirements: Each core in the lot shall have a minimum air content of 3.0 %. Each core in the lot shall have a maximum spacing factor of mm PRODUCTION General Subsection of OPSS 1350 is amended by the addition of the following: Cementitious materials shall not be added by bags or sacks or storage facility remote from the ready mix plant. Concrete shall be free of lumps and segregation as specified elsewhere in this special provision. May 2005 Page 5 of 24 SSP 904S13

6 Temperature Control - General Clause of OPSS 1350 is amended by deletion of the first paragraph and replacing it with the following: The temperature of the concrete at the time of discharge from the truck shall be at or between 10 o C and 25 o C Hot Weather Concrete Clause of OPSS 1350 is amended by deletion of the last sentence Trial Batch Clause of OPSS 1350 is deleted and replaced by requirements stated elsewhere in this special provision. Section of OPSS 1350 is amended by the addition of the following subsection: Primary and Back-Up Ready Mix Concrete Plants The primary plant and back-up plant(s) shall use the same aggregates, cementing materials and admixtures Cylinder Moulds Section of OPSS 904 is deleted and replaced by the following: The cylinder moulds shall have a nominal inside diameter of 100 mm and a nominal height of 200 mm. Moulds shall be made of plastic conforming to CAN/CSA A23.2-1D, with a lid. The lids shall be chemically and physically compatible with the concrete and shall provide watertight closure for the moulds CONSTRUCTION General Clause of OPSS 904 is amended by the deletion of the fifth paragraph and the addition of the following: The Contractor shall not exceed the maximum concrete production rate identified at the time of mix design submission, and shall monitor concrete production to ensure that this rate is not exceeded. The Contractor shall ensure that no segregation of the concrete occurs. Under no circumstances shall concrete which is segregated be placed in the work. The Contractor shall take measures to avoid the formation of lumps in the concrete. If any visible lumps are present in the concrete, they must be removed, and under no circumstances shall concrete lumps be placed in the work. If more than three visible lumps are identified in a load of concrete, the remainder of the load shall be immediately rejected and no further concrete from that truckload placed in the work. May 2005 Page 6 of 24 SSP 904S13

7 If more than three truckloads during the day s work are observed to contain more than three lumps per truck, concrete placement shall be stopped at the end of the day or at the end of the placement of the specific structure component, whichever comes first. No further concrete shall be placed until: The Contractor has provided an explanation of the reasons for the lumps, and identified the steps that will be taken to eliminate the reoccurrence of lumps in future work, A trial batch has been carried out in the presence of the Contract Administrator and the Contract Administrator has verified that the concrete is free of lumps and The Contract Administrator has given approval for placement to proceed Curing Unformed Surfaces Clause of OPSS 904 is deleted and replaced with the following: Fog Misting and Curing Unformed Surfaces Curing with Burlap and Water - General Burlap must be in reasonable condition with no extensive tears or holes. Burlap shall be pre-soaked by immersing it in water for a period of at least 24 hours immediately prior to placing. Two layers of burlap shall be applied to the surface of the concrete. Strips shall overlap 150 mm and shall be held in place without marring the surface of the concrete. The burlap shall be applied immediately after finishing of the concrete surface within 2 to 4 m of the finishing operation and for bridge decks within 2 to 4 m of the pan or screed of the finishing machine. Curing with burlap and water shall be maintained for a minimum period of 7 days. The burlap shall be maintained in a continuously wet condition throughout the curing period, by means of a soaker hose. The burlap shall be covered with a layer of moisture vapour barrier, within 12 hours of placing of the concrete, in a manner which will prevent deformation of the surface of the concrete. Air flow in the space between the moisture vapour barrier and the burlap shall be prevented. Regardless of ambient temperature, moist curing with burlap and water shall be provided at all times. During cold weather, burlap shall be prevented from freezing Fog Misting of Structure Decks, Approach Slabs, Curbs and Sidewalks Fog mist shall be applied continuously from the time concrete is deposited in the deck, approach slab, curb or sidewalk until it is covered with burlap, in such a way as to maintain high relative humidity above the concrete and prevent drying of the concrete. The Contractor shall provide fog misting by hand held fogging wand(s) and may also employ a fogging system mounted on the finishing machine. The fog misting shall be applied such that water does not drip, flow or puddle on the concrete surface during fog misting. May 2005 Page 7 of 24 SSP 904S13

8 Water from fog misting nozzles shall not be applied directly to finishing equipment or to the concrete in such a way that the water will be worked into the surface of the concrete. No material shall be applied to concrete as a finishing aid Curing of Structure Decks, Approach Slabs, Curbs and Sidewalks Structure decks, approach slabs, curbs and sidewalks shall be cured as detailed in clause of this special provision. Water shall not be allowed to drip, flow or puddle on the concrete surface when placing the burlap or at any time before the concrete has achieved final set. Where waterproofing is to be applied to a structure deck following curing with burlap and water, the deck shall be air dried for at least 72 hours prior to the application of waterproofing Curing Other Unformed Surfaces Other unformed surfaces shall be cured as detailed in clause of this special provision. Water shall not be allowed to drip, flow or puddle on the concrete surface, when placing the burlap or at any time before the concrete has achieved final set Curing Formed Surfaces Clause of OPSS 904 is deleted in its entirety and replaced with the following: Barrier Walls and Parapet Walls The concrete in the barrier walls and parapet walls shall be cured as detailed in clause of this special provision. Wet burlap shall be applied to the top (unformed) surface of the barrier wall or parapet wall within 2 to 4 m from the finishing operation, without damaging or marring the surface of the concrete. A soaker hose shall be placed along the top of the barrier wall or parapet wall and put into operation as soon as the barrier wall or parapet wall concrete has achieved final set. Structure barrier wall or parapet wall forms shall be removed no later than 24 hours after concrete placement and the concrete in the barrier wall or parapet wall shall be covered immediately with wet burlap and moisture vapour barrier. The burlap shall be kept continuously wet by means of the soaker hose for the remainder of the minimum curing period of 7 days. May 2005 Page 8 of 24 SSP 904S13

9 Curing Other Formed Surfaces Wet burlap shall be applied to exposed areas of formed components immediately after the finishing operation, without damaging or marring the surface of the concrete. A soaker hose shall be placed along the top of the component and put in operation as soon as the concrete has achieved final set. Formed surfaces will require no additional curing where the formwork is left in place for a minimum of 7 days. Where the formwork is removed in less than 7 days, formed surfaces shall be cured as detailed in clause of this special provision for the remainder of the minimum curing period of 7 days Concrete Placing Temperature Clause of OPSS 904 is deleted Placing Restrictions Clause of OPSS 904 is amended by deletion of the last sentence Concrete Placing Temperature Clause of OPSS 904 is deleted Temperature Records Clause of OPSS 904 is deleted Surface Finish Formed Surfaces General Clause of OPSS 904 is amended by the addition of the following sentence: Textile form liners shall not be used with high performance concrete Frequency of Testing Clause of OPSS 904 is deleted and replaced by the following: Slump, air content and temperature tests shall be carried out for each load of concrete. A set of three cylinders for determination of compressive strength shall be cast at the frequency detailed elsewhere in the contract. Additional cylinders to be used for information purposes shall be cast when requested by the Contract Administrator Preparing Test Cylinders Clause of OPSS 904 is amended by deletion of the following: The second sentence in the second paragraph is deleted. May 2005 Page 9 of 24 SSP 904S13

10 Concrete Strengths 35 MPa or Greater Clause is deleted in its entirety. Clause is amended by the addition of the following: Special Requirements for High Performance Concrete Trial Batch All mix designs for high performance concrete bridge decks require verification by testing of a trial batch. If the contract does not include a bridge deck, the mix design that represents the largest proportion of high performance concrete shall be tested. Each trial batch shall consist of a load of concrete, of the maximum size to be used on the contract. The Contractor shall use the trial batch as a means of assessing slump retention, workability, and ease of finishing to verify the concrete s suitability for the work; and verifying that the compressive strength, air void system, and rapid chloride permeability meet the requirements of this special provision. The trial batch testing shall be carried out at least 35 days prior to commencement of placement of high performance concrete in the work. The concrete shall be produced at the same ready-mix plant that the Contractor intends to use for the contract work and shall be transported in a ready mix truck to the job site, or a location in its immediate vicinity acceptable to the Contract Administrator, where it shall be sampled and tested in the presence of the Contract Administrator. The trial batch shall be carried out using the same batching sequence, mixing time, and production methods to be used in the HPC placement. The trial batch shall simulate the conditions necessary to produce the maximum concrete production rate identified by the Contractor. Addition of superplasticizer must be the same (plant or job site) for the trial batch as for the intended contract work. Prior to placing high performance concrete, the contractor shall submit documentation to the Contract Administrator verifying that trial batch concrete meets the requirements of this special provision for: - air content, slump and temperature of the plastic concrete, - compressive strength at 28 days, - rapid chloride permeability at 28 days, - air void system parameters of hardened concrete, Another trial batch shall be carried out if the following requirements are not met: 1. Compressive strength, air void system and rapid chloride permeability requirements of this special provision, 2. Segregation and lump restrictions of this special provision, 3. Workability and retention of slump within limits that allow the contractor to place the concrete within the specified tolerances. Multiple trial batches may be made and tested concurrently. May 2005 Page 10 of 24 SSP 904S13

11 When approved by the Contract Administrator, the concrete from trial batch(es) may be incorporated into parts of the structure that require concrete of specified strength lower than 50 MPa Trial Slab for Structure Decks Contractors, who have not had prior experience with placing a high performance concrete bridge deck on a previous ministry contract, shall demonstrate their ability to successfully handle, place, fog mist, finish and cure the high performance concrete before any concrete is placed in the deck. To demonstrate this ability the Contractor shall cast a trial slab of dimensions approximately 10 m long by 225 mm thick by the width of the deck to be placed. Location of the trial slab shall be proposed by the Contractor and must be approved by the Contract Administrator. To simulate the effect of travel time, the trial slab location shall not be farther from a ready mix plant than the job site. In the event that the trial slab location is closer to the plant than the job site, the discharge from the ready mix truck shall be delayed sufficiently to match the estimated travel time. The trial slab shall be constructed with the same concrete that is to be placed in the deck, supplied by the same ready mix plant and shall be placed, fog misted, finished and cured as required by the contract documents using the same personnel, methods and equipment that the Contractor intends to use in the work. At least 24 hours after placing, the Contractor shall remove 4 full depth 100 mm diameter cores, one from each quadrant of the trial slab, and forward them to the Contract Administrator for visual inspection to verify that concrete is properly consolidated and contains no voids or honeycombing. The Contract Administrator will return one core to the Contractor for analysis of air void system parameters, for information purposes. The Contractor shall test the core in accordance with ASTM C457 and shall submit results of the testing to the Contract Administrator as specified in this special provision. Testing shall be carried out by a laboratory and operator which participate in the MTO Air Void Analysis Correlation Program and are on the Ministry s list of laboratories and operators qualified for this test. Placement of high performance concrete in the deck shall not commence until approval is given by the Contract Administrator. The approval shall be based on the Contractor s ability to adequately place, finish and cure the concrete in the trial slab and verification by the Contract Administrator that adequate consolidation was achieved. The approval to place concrete will be given or denied within 24 hours of receiving the cores from the Contractor Air Void System Parameters The Contractor shall achieve an air void system as specified in this special provision. For evaluation of air void system parameters, the Contractor shall remove cores from the hardened concrete and shall test the cores in accordance with ASTM C457, except that a magnification of 100 X to 125 X shall be used. Testing shall be carried out by a laboratory and operators(s) which participate in the MTO Air Void Analysis Correlation Program and are on the Ministry s list of qualified laboratories and operators for this test. The air content shall be reported to one decimal place and spacing factor shall be reported to three decimal places. Rounding-off of test data shall be done in accordance with LS-100. Two cores, 100 mm in diameter and 200 mm long, shall be removed from a lot and tested. Each of the following is defined as a lot: lineal metres of sidewalk, curb, per stage, lineal metres of median, per stage May 2005 Page 11 of 24 SSP 904S13

12 lineal metres of parapet or cast in place concrete barrier wall, per stage square metres of bridge deck, per stage, 5. An abutment, or a stage thereof, 6. A pier. If the total quantity of a component is less than specified above, two cores (per stage) shall be removed and tested. Each core shall be taken at a random location specified by the Contract Administrator. For barrier wall, the cores shall be taken from the lower sloped portion of the wall at the designated locations. For parapet wall, the cores shall be taken from the lower one third of the wall at the designated locations. Care shall be taken to avoid cutting reinforcing steel or other embedments. The contract number, lot number and exact location of each individual core shall be marked legibly on the core with durable ink. The date at which the core was removed shall also be recorded. All cores shall be taken when the concrete is a minimum 7 days of age. Cores shall be cut lengthwise into two halves, with one half to be tested by the Contractor and the other to be forwarded to the Ministry within two weeks of extracting the core (Manager, Concrete Section, Room 15, Building C, 1201 Wilson Avenue, Downsview, Ontario M3M 1J8). If the core contains reinforcing steel or other embedments, it shall be cut lengthwise into two parts with no reinforcing steel in the surface areas to be tested. Both halves shall be marked with a unique identification number. The half core forwarded to the Ministry shall have an information sheet securely attached to it detailing the contract number, lot number and the location or component from which the core was removed. Form A of the concrete mix design for the component shall also be submitted with the core. The Contractor shall fill each core hole immediately after coring with a patching material approved by the Ministry and comparable to the surrounding concrete in terms of strength and permeability. The patching material shall be mixed, handled and cured in accordance with the manufacturer s instructions. Immediately before filling, the inside surface of each core shall be cleaned of the paste left from the coring operation by nylon brushing, and all free water shall be removed. The patch shall be finished flush with the surface of the surrounding concrete. All excess material shall be removed from the surface of the concrete. Air void analysis results obtained by the Contractor shall be forwarded to the Contract Administrator within 21 days of concrete placement. Air void core samples shall be retained by the Contractor until Final Acceptance, as defined elsewhere in the contract documents, and shall be provided to the Contract Administrator on request Air Void System Parameters Referee Testing Referee Testing - General The referee testing shall be carried out on the original core samples using the Contractor s half. The Contractor shall label the cores as Cores for Referee Testing - AVS. Once referee testing is invoked, the Contractor shall make the samples available to the Contract Administrator within 5 business days. Referee testing shall be carried out only once on a sample. The testing shall be carried out by a referee testing laboratory and operator whose names will be provided by the Contract Administrator. May 2005 Page 12 of 24 SSP 904S13

13 The referee testing shall be carried out in conformance with the Ministry s laboratory test method LS-431. The referee testing laboratory will report the referee test results directly to the Contract Administrator. If repolishing is carried out by the referee laboratory, this shall be documented and reported to the Contract Administrator along with referee test results. Representatives of the Contractor and Owner may witness any referee testing. The Contract Administrator will notify the Owner and Contractor of the date of commencement of testing at least 48 hours in advance. Provided that at least 48 hours notice was given, the testing will be carried out regardless of the presence or absence of witnesses. Witnesses shall follow the laboratory s protocol for access to the premises and testing equipment and shall not impede the progress of the testing. Subject to safety requirements, test method timing requirements and equipment limitations, witnesses shall be permitted to observe sample identification, sample condition and test procedures, take notes, view equipment readings and review completed work sheets while in attendance for the testing. Concerns with sample condition and/or sample identification shall be made prior to commencement of testing. Concerns regarding any potential deviation from the applicable test procedure shall be made immediately upon identifying the potential deviation at the time of testing. Any concerns shall be specific in nature and submitted in writing to the laboratory s representative and the other witness at the time of testing. No compensation will be made to the Contractor for any costs incurred in witnessing the referee testing. The cost of the testing shall be $650 for each core. Following completion of referee testing, the referee test cores will be retained by the Contract Administrator until Final Acceptance Air Void System Parameters Referee Testing Invoked by Contractor The Contractor may challenge an air void system result by invoking referee testing. Challenge shall be submitted in writing and given directly or faxed to the Contract Administrator. The referee testing may be invoked when an individual spacing factor or air content result for a core fails to meet the requirements of this special provision. The Contractor shall advise the Contract Administrator of his intent to invoke referee testing within three weeks of concrete placement, at the time of submitting the original test results. When referee testing is invoked, all core samples representing a lot must be referee tested and the original results discarded. The lot referee test results shall replace the original result in the acceptance requirements of this special provision. The Contractor shall be responsible for the cost of referee testing invoked by the Contractor including packaging and shipping of samples Air Void System Parameters -Referee Testing Invoked by Owner The Contract Administrator may challenge air void system results by invoking referee testing. The referee testing may be invoked when one or more of the following conditions are present: Two test results for spacing factor from the same lot vary by more than mm. If the Contract Administrator invokes referee testing, all cores in a lot will be referee-tested. May 2005 Page 13 of 24 SSP 904S13

14 The first ten or more air void system results obtained on cores representing concrete from the same mix design have a coefficient of variation of more than 50% or less than 5%. If the Contract Administrator invokes referee testing, the Contract Administrator will select two cores from the group of ten or more cores for referee testing. There has been a change in laboratories carrying out contractor testing on the contract. If the Contract Administrator invokes referee testing, one out of five cores tested by the new laboratory will be randomly selected for referee testing. One or more MTO audit core test results from a single contract vary from the Contractor s results by more than 2.0% for air content, or more than mm for spacing factor. All cores in a lot will be referee tested. The Owner detects abnormalities through routine contract monitoring processes, or results deviate from what would typically be encountered on a contract. If the Contract Administrator invokes referee testing, the Contract Administrator will identify the cores for referee testing. The referee testing invoked by the Owner may be carried out at any time up to one year after a result is obtained, and must be completed prior to contract Final Acceptance. The Contract Administrator will advise the Contractor of the Owner s desire to invoke referee testing and will identify which samples will be referee tested. The Owner will be responsible for the cost of referee testing invoked by the Owner including packaging and shipping of samples Rapid Chloride Permeability For evaluation of rapid chloride permeability, the Contractor shall remove cores from the hardened concrete and test the cores in accordance with ASTM C Testing shall be carried out at 28 to 32 days of age by a laboratory, which participates in the MTO Rapid Chloride Permeability Correlation Program and is on the Ministry s list of qualified laboratories for this test. Two cores, 100 mm in diameter and at least 125 mm long, shall be removed from a lot. The cores shall be obtained in conformance with CSA A C when the concrete is between 7 to 10 days of age and prior to application of any waterproofing membrane. Cores shall be delivered to a laboratory acceptable to the Ministry within 24 hours of coring. The cores shall be stored at a temperature of 23 o ±2 o C in a moist condition until time of testing. Testing shall be carried out in conformance with ASTM C1202 at 28 days to 32 days of age. A 10 mm thick slice shall be cut off from the top of each core before test specimens are cut from it. Two 50 mm long samples shall be cut from each core and tested. Each of the following is defined as a lot: lineal metres of sidewalk, curb, per stage, lineal metres of median, per stage lineal metres of parapet or cast in place concrete barrier wall or parapet wall, per stage square metres of bridge deck, per stage, 5. An abutment, or a stage thereof, 6. A pier. If the total quantity of sidewalk, curb, median, parapet or cast in place concrete barrier wall is less than 500 lineal metres, two cores (per stage) shall be removed and tested. May 2005 Page 14 of 24 SSP 904S13

15 Each core shall be taken at a random location specified by the Contract Administrator. Cores shall not contain reinforcing steel or other embedments. Core holes shall be filled as detailed in Clause of this special provision. Rapid chloride permeability results obtained by the Contractor shall be recorded and forwarded to the Contract Administrator within 37 days of concrete placement. Rapid chloride permeability core samples and laboratory original records shall be retained by the Contractor until Final Acceptance and shall be provided to the Contract Administrator upon request Control of Temperature and Temperature Difference for High Performance Concrete For each placement the Contractor shall take steps before, during and following placement of concrete to ensure that the temperature of the concrete and the temperature difference within the concrete is controlled within the specified limits. The requirements of this section must be met regardless of ambient air temperature and do not change the requirements for cold weather or hot weather concrete stated elsewhere in the Contract. During the seven days following placing of the high performance concrete, the Contractor shall provide protection to ensure that the concrete temperature and temperature differences stay within the limits specified below: 1. The temperature of the concrete shall not fall below 10 o C or exceed 70 o C. 2. The temperature difference between the centre of the concrete and the surface of the element shall be controlled so that the temperature difference does not exceed 20 o C. The Contractor shall monitor the concrete temperature. The Contractor shall supply and install thermocouple wires and associated instrumentation with a combined accuracy of ± 1 o C capable of recording and displaying temperature. The instrumentation shall include dataloggers capable of recording at hourly intervals or less. Thermocouples shall be installed in bridge decks and substructure elements in locations where the concrete is expected to reach the highest temperature and at the surface of concrete. For substructure elements, thermocouples shall be installed in sets of two consisting of a central and surface thermocouple. For bridge decks, thermocouples shall be installed in sets of three consisting of one mid-depth thermocouple and two surface thermocouples. The surface thermocouples shall be placed immediately above or the shortest distance from the corresponding central thermocouple. The surface thermocouples shall be installed beneath the burlap in contact with the surface concrete or imbedded in the concrete within 5 mm of the surface and, for bridge decks, the second surface thermocouple shall be placed inside the bottom form. The number of sets shall be in accordance with Table 1. May 2005 Page 15 of 24 SSP 904S13

16 Table 1 Number of Thermocouple Sets for Temperature Measurement Number of Thermocouple Sets Decks 1 1) a minimum of three per stage, or per deck if deck is not placed in stages 2) when diaphragm is cast together with a deck a minimum of four per stage Substructure Elements or stages thereof (abutments, pier columns, pier caps) Minimum of three Note: 1 As a minimum, a set of three thermocouples shall be located at the beginning, middle, and final portion of the deck placement, and in the diaphragm. Recording of temperature shall begin at the start of placement. The temperature shall be recorded automatically at intervals not greater than 1 hour until the end of the 7-day curing period. The Contractor s personnel shall also monitor and verify temperature every 4 hours or more frequently for the first 72 hours of the curing period and shall take necessary action to maintain the temperature within the specified limits. For the remaining 4 days of the curing period the Contractor s personnel shall continue to monitor and verify the temperature every 12 hours and shall take necessary action to maintain the temperature within the specified limits. Datalogger temperature records and a record of any actions taken shall be forwarded to the Contractor Administrator each day. At the end of the temperature monitoring period, the Contractor shall submit a complete temperature record including graphical plot (temperature vs. time), to the Contract Administrator. The Contract Administrator shall be provided the necessary access to the location to verify temperature readings. The digital temperature indicators shall be left in place until the end of the 7-day curing period. If the datalogger does not have a digital display that allows the Contract Administrator to verify temperature, the Contractor shall provide the Contract Administrator with the necessary instruments to allow the Contract Administrator verification of thermocouple function and readings Cracks in Formed and Unformed Surfaces The Contractor shall inspect all areas of cracking to identify and document any areas where cracks measuring 0.3 mm in widths or greater are present. The documentation shall include location of cracking, width of cracks and crack density. This shall be done no sooner than two weeks following the completion of curing, except for waterproofed bridge decks. For waterproofed bridge decks the inspection of the surface to be waterproofed shall be carried out after completion of curing and before application of waterproofing. Results of the inspection shall be reported to the Contract Administrator. May 2005 Page 16 of 24 SSP 904S13

17 The Contractor shall compare the width and density of cracks with values in Table 2 to identify areas requiring repair or replacement, and shall determine the limits of repair/replacement. This information shall be provided to the Contract Administrator along with a Plan for remedial action to be taken. The Contract Administrator shall verify that the Plan addresses all areas of deficiency. No repairs shall proceed until the Contract Administrator has accepted the proposed limits of repair/replacement. Repairs shall be in accordance with OPSS 932. The removals and preparation of concrete shall be in accordance with OPSS 930. The Contractor shall not proceed with waterproofing of a bridge deck until repairs have been completed and permission to waterproof has been given by the Contract Administrator. May 2005 Page 17 of 24 SSP 904S13

18 Table 2 COMPONENTS WIDTH 1 OF CRACK (mm) TREATMENT OF CRACKED AREAS Components within the splash zone Decks to be waterproofed and paved 0.50 Repair Exposed decks, > 0.30 a) Repair cracks in the areas where linear measurement of crack per m 2 is < 5 m Barrier wall, parapet wall, sidewalk, median on a structure b) Remove and replace the cracked areas where linear measurement of crack per m 2 is 5 m > 0.30 a) Repair cracks in the areas where the linear measurement of crack per linear m of the wall, sidewalk or median measured along the side facing traffic is < 5 m. b) Remove and replace the cracked areas where the linear measurement of crack per lineal m of the wall, sidewalk or median measured along the side facing traffic is 5 m. Curb on a structure > 0.30 a) Repair cracks in the areas where the linear measurement of crack per linear meter of the curb is < 1.5 m. Other components within the splash >0.30 Repair zone 2 b) Remove and replace the cracked areas where the linear measurement of crack per linear meter of the curb is 1.5 m. Components outside of the splash zone 1.00 Repair Notes: 1 Width of crack at widest point (not average width of crack) 2 Other components within the splash zone include: a) Surfaces of columns within 10 m horizontally and 5 m vertically of a roadway measured from the edge of the nearest travelled lane. Pier caps are exempt from this requirement except as detailed below. b) Side and end surfaces of pier shafts within 10 m horizontally and 5 m vertically of an existing or future roadway measured from the edge of the nearest travelled lane. c) Bearing seats and sides of pier shafts and columns, including pier caps, below expansion joints within 5 m measured vertically from the bearing seat. d) Top and side surfaces of bases for pole and sign structures that are attached to bridges. May 2005 Page 18 of 24 SSP 904S13

19 e) Top surfaces of expansion joint end dams Concrete in Structure and in Deck Subsection of OPSS 904 is amended by the addition of the following: Demonstration of Fog Misting At the time of the dry run the Contractor shall demonstrate that the performance of the fog misting equipment meets the specified requirements QUALITY ASSURANCE General Clause of OPSS 904 is amended by deletion of the second paragraph Acceptance Clause of OPSS 904 is amended by the addition of the following Cracks in Formed and Unformed Surfaces The Contract Administrator will accept the components with formed and unformed surfaces based on verification that the cracks in the completed work were treated in accordance with clause of this special provision Rapid Chloride Permeability Acceptability of rapid chloride permeability shall be based on average of results obtained on two cores representing a lot. Lots with an average value of rapid chloride permeability exceeding 1000 coulombs and less than or equal to 2000 coulombs will be accepted with price reduction as detailed in subsection of this special provision. Lots with rapid chloride permeability value exceeding 2000 coulombs will be considered unacceptable. Unacceptable concrete shall be removed and replaced at the Contractor's expense Air Void System For a lot to be considered acceptable, both cores shall each have air content of 3.0% or more and spacing factor of mm or less. Acceptable lot will be subject to full payment or bonus payment. The bonus for an acceptable lot will be calculated in accordance with the clause Unacceptable lot is a lot represented by one or two cores that fail to meet the air void system parameters. Unacceptable lots shall be removed and replaced at the Contractor's expense; where the Owner permits the work to remain in place a penalty will be calculated in accordance with the clause Unacceptable lots will not be eligible for bonus. All replacement lots shall be accepted on the same basis as the original lot. May 2005 Page 19 of 24 SSP 904S13

20 Where referee testing is carried out, the referee test results will replace the original results in the acceptance requirements of this special provision MEASUREMENT FOR PAYMENT Non Measurement Subsection of OPSS 904 is amended by the addition of the following: High Performance Concrete in Substructure High Performance Concrete in Structure High Performance Concrete in Approach Slab High Performance Concrete in Deck High Performance Concrete in Barrier Walls High Performance Concrete in Parapet Walls High Performance Concrete in Substructure and Retaining Walls There will be no measurement for the above items when designated in the tender as Lump Sum BASIS OF PAYMENT General Subsection of OPSS 904 is amended by the addition of the following: High Performance Concrete in Substructure - Item High Performance Concrete in Structure - Item High Performance Concrete in Approach Slab - Item High Performance Concrete in Deck - Item High Performance Concrete in Barrier Walls - Item High Performance Concrete in Parapet Walls Item High Performance Concrete in Substructure and Retaining Walls - Item Payment at the contract price for the appropriate high performance concrete tender item shall be full compensation for all labour, equipment and material to do the work subject to payment adjustments as specified in and below. Subsection of OPSS 904 is deleted and replaced with the following: Deck Joint Assemblies and Bearings Payment for deck joint assemblies and bearings will be included in the item "Concrete in Deck" or High Performance Concrete in Deck unless they are included in another tender item or there are separate tender items for deck joint assemblies and bearings. Section of OPSS 904 is amended by the addition of the following: May 2005 Page 20 of 24 SSP 904S13

21 Air Void System General For the purpose of calculating bonus or penalty, the Contract Administrator will determine the quantity of concrete in lot(s) using the dimensions in the Contract Documents Payment Adjustment for Acceptable Lot The bonus payment for an acceptable lot will be calculated by averaging bonus values corresponding to individual core results. The values in dollars per m 3 of concrete are given in Table 3. B= (B1 + B2)/2 Where: B = bonus in dollars per m 3 of concrete in the lot B1 and 2 = bonus for cores 1 and 2 in dollars per m 3 of concrete in the lot (from Table 3). Bonus for Acceptable Lot = Lot Quantity (m 3 ) x B Payment for Unacceptable Lot Payment will be calculated for each unacceptable lot by averaging pay factors corresponding to individual core results. The pay factors in percent of tender price for the item per lot are given in Table 4. Where one core in an unacceptable lot meets the specification requirements for air void system, the core will be assigned a pay factor of 100%. Payment for unacceptable lot will be calculated according to the following: P= (P1+P2)/2 Where: P = pay factor for the lot (%) P1 and 2 = pay factor for cores 1 and 2 in % (from Table 4) Payment Reduction for a Lot = (Lot Quantity (m 3 )/Tender Quantity (m 3 )) x (Tender Lump Sum Price) x ((100-P)/100) Total Payment Reduction= Σ Payment Reduction for lots Rapid Chloride Permeability For the purpose of calculating penalty, the Contract Administrator will determine the quantity of concrete in lot(s) using the dimensions in the Contract Documents. Where rapid chloride permeability value exceeds 1000 coulombs and is less than or equal to 2000 coulombs, the payment reduction will be calculated and applied as follows: Pa = (C-1000) 5 May 2005 Page 21 of 24 SSP 904S13

22 Pa = payment reduction in dollars per m 3 C = average rapid chloride permeability of a lot Payment Reduction per Lot = Lot Quantity (m 3 ) x Pa Table 3 BONUS FOR AIR VOID SYSTEM PARAMETERS IN HARDENED CONCRETE Bonus in $/m 3 Spacing Factor (mm) Air Content (%) < Table 3, continued Spacing Factor (mm) Air Content (%) < Note: Where a core has air content of 3% or higher, and spacing factor 0.250mm or lower but its air void system parameters are outside the range given in Table 3, it will be assigned a value of 0 for the purpose of calculating a bonus. May 2005 Page 22 of 24 SSP 904S13