CONSTRUCTION SPECIAL PROVISION FOR STRUCTURE REHABILITATION - CONCRETE PATCHES, REFACING AND OVERLAYS

Transcription

1 AMENDMENT TO OPSS 930, MAY 1994 Special Provision No. 109S50 July 2007 CONSTRUCTION SPECIAL PROVISION FOR STRUCTURE REHABILITATION - CONCRETE PATCHES, REFACING AND OVERLAYS OPSS 930, Construction Special Provision for Structure Rehabilitation - Concrete Patches and Overlays (May 1994) is deleted in its entirety and replaced with the following Special Provision SCOPE This specification covers the requirements for concrete structure rehabilitation, including; concrete patches, concrete refacing, normal concrete overlays and silica fume concrete overlays REFERENCES This specification refers to the following standards, specifications or publications: Ontario Provincial Standard Specifications, Construction: OPSS 904 OPSS 905 OPSS 919 OPSS 928 OPSS 929 OPSS 932 Concrete Structures Steel Reinforcement for Concrete Formwork and Falsework Structure Rehabilitation Concrete Removal Abrasive Blast Cleaning Concrete Construction Crack Repair Concrete Ontario Provincial Standard Specifications, Material: OPSS 1002 OPSS 1301 OPSS 1302 OPSS 1350 Aggregates Concrete Cementing Materials Water Concrete Materials and Production American Association of State Highway and Transportation Officials AASHTO M Standard Specification for Burlap Cloth made from Jute or Kenaf American Society for Testing and Materials Standards: ASTM A53/A53M ASTM C Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless Sheet Materials for Curing Concrete July 2007 Pg. 1 of 19 SSP 109S50

2 Canadian Standards Association Standards: CSA A23.1/A Concrete Materials and Methods of Concrete Construction/ Methods of Test for Concrete CSA A C Obtaining and Testing Drilled Cores for Compressive Strength Testing CSA C22.2 No M1984 (1992) Rigid PVC (Unplasticized) Conduit CSA G30.5-M1983 (R1998) Welded Steel Wire Fabric for Concrete Reinforcement CSA G164-M92 (R1998) Hot Dip Galvanizing of Irregularly Shaped Articles Ministry of Transportation Publications: MTO Laboratory Testing Manual: LS-430 LS-435 LS-601 LS-607 Method of Test for Bond Strength by Tensile Load Method of Test for Linear Shrinkage of Concrete Materials Finer Than 75 μm Sieve in Mineral Aggregates by Washing Determination of Percent Crushed Particles in Processed Coarse Aggregate DEFINITIONS For the purpose of this specification the following definitions apply: Cold Weather: means those conditions when the air temperature is at or below 10 o C. It is also considered to exist when the air temperature is at or is likely to fall below 10 o C within 96 hours after concrete placement. Temperature refers to shade temperature. Concrete Patches, Formed Surfaces: applies to concrete patches where at least one face of the patch requires formwork. Concrete Patches, Unformed Surfaces: applies to concrete patches located in the top surface of decks, sidewalks and curbs where no formwork is required. Form and Pump Placement Method: means a method of placing concrete by pumping directly into formwork through injection ports. Hot Weather: means those conditions when the air temperature is at or above 28 o C. It is also considered to exist when the air temperature is at or is likely to rise above 28 o C within 24 hours after concrete placement. Injection Port: means a mechanical device with a shut-off valve that is attached to the formwork and connected to the discharge line of a pump to facilitate delivery of concrete directly into formwork. Rehabilitation: means any modification, alteration, or improvement to a structure or its components, which is designed to correct defects or deficiencies. 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. Silica Fume Concrete: concrete which includes silica fume and may in addition include other supplementary cementing materials, having a specified rapid chloride permeability at 28 days of 1000 coulombs or less. July 2007 Pg. 2 of 19 SSP 109S50

3 Structure: means any bridge, culvert, tunnel, retaining wall, wharf, dock, guideway or any part thereof DESIGN AND SUBMISSION REQUIREMENTS Mix Design The Contractor shall submit the concrete mix design(s) to the Contract Administrator according to OPSS 1350 with the exception that the test data for linear shrinkage shall be submitted within 40 days of the mix design submission, for information purposes only, according to LS Cold Weather Protection General One week prior to the commencement of concrete production in cold weather, a description of the methods to be used to control the concrete temperature shall be submitted to the Contract Administrator. The submission shall be accompanied by samples of insulation, if requested by the Contract Administrator and shall contain the following information: a. Weather conditions for which the description applies. b. Type of insulation, metric R value and number of layers to be used. c. Description of housing and heating. d. Method of withdrawal of protection to avoid sudden temperature change in the concrete. e. Method of ensuring cold weather protection measures are maintained when work requiring adjustment to the protective measure is being performed Temperature Records Temperature records shall be forwarded to the Contract Administrator at the end of every day. At the end of the cold weather protection period, the Contractor shall submit a complete temperature record consisting of a summary of the recorded temperatures and a graphical plot of temperature vs. time to the Contract Administrator Hot Weather Concreting One week prior to the commencement of concrete production in hot weather, a description of the methods to be used to control the concrete temperature shall be submitted to the Contract Administrator Placement Methods When the form and pump placement method is specified in the Contract Documents, four copies of the details of the placement method shall be submitted to the Contract Administrator at least one week prior to commencement of the work. The details shall include methodology and equipment to be used and shall bear the seal and signature of a Professional Engineer. July 2007 Pg. 3 of 19 SSP 109S50

4 MATERIALS Normal and Silica Fume Concrete The concrete shall be according to OPSS 1350 with the following exceptions: a. The minimum specified 28-day compressive strength shall be 30 MPa except for silica fume overlays, which shall be 40 MPa. b. The nominal maximum size of coarse aggregate shall be 13.2 mm for concrete patches, concrete refacing and overlays less than 100 mm in thickness. c. When the thickness of the repair exceeds 100 mm, the nominal maximum size of coarse aggregate shall be 19 mm. d. Coarse aggregates for overlays shall consist of a minimum of 60% crushed particles when tested according to MTO LS-607 and shall have 1.00% by mass maximum passing the 75 μm sieve when tested according to MTO LS-601. Coarse aggregate for overlays that form the bridge deck riding surface shall be composed of at least 80% siliceous rocks and minerals. e. For concrete patches, the Contractor may submit a proposal to the Contract Administrator for approval to use a proprietary patching material, in areas where the greatest width or length dimension of the patch is less than 300 mm Anchors Anchors for the attachment of the welded steel wire fabric to the concrete surface shall be galvanized according to CAN/CSA G164 and be of adequate length and strength to resist a pull-out force of 1.0 kn Bonding Agent The bonding agent shall consist of Portland cement and sand mixed with sufficient water to form a stiff mixture. The Portland cement shall be according to OPSS 1301 and sand shall be according to OPSS The consistency of the mixture shall be such that it can be applied with a stiff brush to the concrete surface, in a thin even coating that will not run or puddle Burlap Burlap shall be according to AASHTO M182 Class 4 and shall be free from substances which are deleterious to concrete. The burlap shall have no tears or holes Drainage Tubes Rigid P.V.C. drainage tubes shall be according to CSA C22.2 No Galvanized steel drainage tubes shall be according to ASTM A53/A53M; galvanizing shall be according to CAN/CSA G Forms Forms shall be according to OPSS 919. July 2007 Pg. 4 of 19 SSP 109S50

5 Moisture Vapour Barrier The moisture vapour barrier shall be a white opaque polyethylene film according to ASTM C171 and shall not be less than 100 μm thick Proprietary Patching Materials Proprietary patching materials shall be from the Ministry s list of Concrete Patching Materials. The list of proprietary patching material shall be obtained from the Contract Administrator Tie Wire Tie wire shall be according to OPSS Water Water used for curing, fog-misting of concrete, pre-soaking of burlap and bonding agent shall be according to OPSS Welded Steel Wire Fabric Welded steel wire fabric shall be welded galvanized steel and shall be according to CSA G30.5. Galvanizing shall be according to CAN/CSA G EQUIPMENT Bridge Deck Finishing Equipment - Overlays The finishing equipment used for overlays including finishing machine, screed rails, screed rail chairs and work bridges shall be according to OPSS Buggies Buggies used for transporting and placing the concrete may be hand operated or motorized. Motorized concrete buggies shall have a capacity no greater than 0.5 m Compressor - Air Blasting The compressor for air blasting shall have a minimum capacity of 3.5 m 3 /min. The compressed air shall be free from oil and other contaminants Consolidating Equipment Consolidating equipment shall be according to OPSS Fog Misting Equipment Fog misting equipment shall be provided for the curing of the silica fume concrete overlay. The Contractor shall use hand held fogging wand(s) and may also employ a fogging system mounted on the finishing machine. July 2007 Pg. 5 of 19 SSP 109S50

6 Form and Pump Placement Method Equipment When the form and pump placement method is specified in the Contract Documents, the pump shall be a positive displacement type pump and shall be capable of delivering adequate volumes of concrete to maintain a continuous placement Hand Finishing Equipment Hand finishing equipment shall be according to OPSS Mixers The equipment used for mixing concrete shall be according to OPSS 1350 except as specified herein. Stationary mixers for the mixing of bonding agents shall be power driven and capable of uniformly mixing the materials Sawing Equipment - Overlays The sawing equipment shall be self-propelled and capable of sawing the overlay concrete full depth in one pass Straight Edges Straight edges shall be according to OPSS CONSTRUCTION General Typical locations and areas of repair are as shown on the Contract Drawings, however, the actual locations and extent of repair will be as determined during the layout of the repair areas according to OPSS 928 and as directed by the Contract Administrator Operational Constraints The Contract Administrator shall be notified of the intent to place the overlay, concrete patches concrete refacing one business day prior to the commencement of the placing operation. The work shall not proceed until the concrete surface preparation has been completed as per this specification and verified by the Contract Administrator. Construction equipment will be permitted on the bridge deck or other concrete components provided that: a. Contamination by oil or other deleterious substances shall be prevented. b. Equipment, vehicles and runways shall not be supported by reinforcing steel. c. Only the finishing machine and buggies used to place concrete shall be allowed on the abrasive blast cleaned portions of the deck or other concrete components. No other vehicles or equipment, including concrete ready mix trucks shall be permitted. d. Heavy vehicles such as concrete ready mix trucks or dump trucks will not be permitted on any portion of the deck, within a span, once concrete removals within the deck have commenced in that span. Concrete shall not be placed when the air temperature or existing concrete surface temperature is below 10 o C or July 2007 Pg. 6 of 19 SSP 109S50

7 likely to fall below 10 o C, or is above 30 o C or likely to rise above 30 o C, throughout the duration of the concrete placing operation. Prior to placing new concrete, the Contractor shall demonstrate to the Contract Administrator that the substrate temperatures meet the Contract requirements by measuring and recording the substrate temperatures using a contact thermometer or infrared thermometer. Concrete shall not be placed adjacent to any new concrete less than 48 hours old. If the ambient air temperature falls below 10 o C within the first 48 hours after placement of concrete, the 48 hour time requirement shall be extended to 96 hours. The Contractor shall ensure that during the curing and/or protection period the concrete temperature does not fall below 10 o C or exceed 70 o C. For staged overlay construction, concrete shall not be placed adjacent to any new concrete having a compressive strength less than 20 MPa. All concrete overlay placements 3 m or wider, shall be finished with bridge deck finishing equipment. No construction vehicles, equipment or traffic, with the exception of sawcutting equipment, shall be permitted on the finished surface of the overlay or patches until the curing and cold weather protection period has elapsed and a minimum of 80% of the specified compressive strength has been attained. Prior to seasonal shutdown, operations shall be scheduled in such a manner to ensure that the overlays, concrete patches and concrete refacing are completed in all areas where concrete removal has commenced. No reinforcing steel shall be left exposed during seasonal shutdown Normal Concrete Overlay Silica Fume Concrete Overlay Minimum Thickness of Overlay The thickness of the overlay shall meet the requirements of the Contract Drawings with no areas less than 45 mm in thickness Surface Preparation All concrete surfaces against which new concrete is to be placed shall be clean, sound and free from loose or unsound fragments, coatings and any other foreign substances or debris and shall be sufficiently rough to ensure that a full bond is developed with the new concrete. The portion of curb face, barrier wall or parapet wall and all existing concrete surfaces, which have not been scarified, against which new concrete is to be placed, shall be uniformly roughened by means of scabbling, chipping or bushhammering. A surface profile of 5 ± 2 mm shall be achieved by exposing the aggregates across the entire surface. All concrete surfaces and reinforcing steel to receive the overlay shall be abrasive blast cleaned according to OPSS 929. Immediately prior to wetting the concrete surface, all dust and loose material shall be removed from the prepared July 2007 Pg. 7 of 19 SSP 109S50

8 surface by using compressed air, except where anode mesh is to be used. When anode mesh is required, the concrete surface shall be pressure washed with water using a pressure not less than 1.4 MPa, with the anode mesh in place. The pressure washing shall take place within four hours of the application of the bonding agent. All debris resulting from drilling of anchor holes and other accumulated dirt adhering to the anode or concrete surfaces shall be removed. All concrete surfaces to receive an overlay shall be maintained in a wet condition for a minimum period of six hours prior to the application of the bonding agent. Excess water shall be removed from the surface using compressed air, immediately prior to the application of the bonding agent Placing of Screed Rails Supports for the screed rails shall be installed outside the area to be waterproofed. The screed rails shall be continued beyond the deck, at each end, to a length that will enable the finishing machine to be driven beyond the end of deck Trial Run The Contractor shall notify the Contract Administrator at least one business day before the trial run, of the intent to conduct a trial run. A trial run shall be made before each placing operation, in the presence of the Contract Administrator, to ensure that the minimum thickness of the overlay can be achieved. Where the trial run indicates that an unsatisfactory thickness will result, the screed rails shall be adjusted in order to obtain the minimum thickness and the trial run repeated in the area of screed rail adjustment. The overlay shall not be placed until the Contract Administrator is satisfied that the minimum thickness of the overlay can be achieved and permission to proceed with the overlay is given in writing to the Contractor. At the time of the trial run for silica fume concrete overlays, the Contractor shall demonstrate in the presence of the Contract Administrator, their ability to successfully fog mist. The same equipment shall be used to fog mist the overlay Placing A thin even coat of bonding agent shall be brushed onto all prepared vertical and horizontal surfaces against which the overlay will be placed. After application of the bonding agent, any fine aggregates separated from the mixture or any excess bonding agent shall be removed from the surface of the concrete. The bonding agent shall be applied within 30 minutes after mixing and shall not be permitted to dry prior to placing concrete on it. In the event that the bonding agent has dried, it shall be removed and reapplied prior to placing the overlay. Any bonding agent or concrete deposited in areas other than the intended point of discharge shall be removed immediately. The method of placing concrete shall be according to OPSS 904. Concrete for partial depth removal areas shall be placed at the same time as the overlay. Unless otherwise specified in the Contract Documents, concrete for full depth removal areas shall be placed prior to placing the overlay and left with a rough surface finish. July 2007 Pg. 8 of 19 SSP 109S50

9 Construction Joints Construction joints will be permitted only where shown in the Contract Drawings or in the case of unexpected interruptions during the placing operation, as directed by the Contract Administrator. All construction joints shall be formed using bulkheads. The height of the bulkhead shall match the thickness of the overlay. The edge and face created by the bulkhead shall be a clean vertical face, free from any defects such as honeycombing and spalls. If the construction joint formed by the bulkhead is deemed unacceptable by the Contract Administrator, a new construction joint shall be created by sawcutting back to a limit where the quality of concrete is acceptable to the Contract Administrator Surface Finish Surface finish shall be according to OPSS Surface Tolerance Surface tolerance shall be according to OPSS Surface Texture Where the surface of the overlay forms the driving surface of the bridge deck, the surface shall be given a texture with a wire broom or comb, having a single row of tines. The required texture shall be transverse grooves, which may vary from 1.5 mm width at 15 mm centres to 4.5 mm width at 20 mm centres with a groove depth varying from 3.0 mm to 4.5 mm. The texture shall extend uniformly to within 300 mm of the curb or barrier wall/parapet wall Curing Normal concrete overlay shall be cured according to the requirements for curing with burlap and water requirements specified in OPSS 904 for a minimum curing period of four days. Silica fume concrete overlay shall be cured according to the requirements for high performance concrete (HPC) specified in OPSS 904 for a minimum curing period of seven days Concrete Patches, Formed Surface Concrete Patches, Unformed Surface Concrete Patches, Form and Pump Concrete Refacing Concrete Refacing, Form and Pump Surface Preparation All concrete surfaces against which new concrete is to be placed shall be clean, sound and free from loose or unsound fragments, coatings and any other foreign substances or debris and shall be sufficiently rough to ensure that a full bond is developed with the new concrete. July 2007 Pg. 9 of 19 SSP 109S50

10 All existing concrete surfaces, against which new concrete is to be placed, shall be uniformly roughened by means of scabbling, chipping or bushhammering. A surface profile of 5 ± 2 mm shall be achieved by exposing the aggregates across the entire surface. All concrete surfaces and reinforcing steel to receive new concrete shall be abrasive blast cleaned according to OPSS 929. Immediately prior to wetting the concrete surface, all dust and loose material shall be removed from the prepared surface of the repair area by using compressed air. The surface of the existing concrete shall be maintained in a wet condition for a period of six hours prior to placing any new concrete. Prior to placing concrete, excess water shall be removed from the surface using compressed air Placement of Welded Steel Wire Fabric When welded steel wire fabric is specified in the Contract Documents, it shall not be installed until after the concrete surface and exposed reinforcing steel in the repair area have been abrasive blast cleaned. The welded steel wire fabric shall not be abrasive blast cleaned at any time. Where there is no exposed reinforcing steel, the wire fabric shall be fastened to the concrete with anchors placed no further than 600 mm apart, in a grid pattern. Where reinforcing steel is exposed, the wire fabric shall be securely fastened to the reinforcing steel by tie wires placed no further than 600 mm apart, in a grid pattern. When the exposed reinforcing steel is not capable of providing rigid support for the wire fabric, anchors shall be used to support the wire fabric. The wire fabric shall be installed flat, tight and in the locations shown in the Contract Drawings, using spacers and anchors. The edges of adjoining wire fabric shall overlap by two-wire spacing plus 100 mm. The wire fabric shall be kept clean of any contamination, which will reduce the bond of the repair material to the wire surface Installation of Anchors and Dowels Holes for anchors and dowels shall be drilled into the concrete in the location and spacing specified in the Contract Documents. They shall be installed in such a way not to cause delamination or other damage to the surrounding concrete. Each anchor shall be installed to resist a pull out force of at least 1.0 kn Formwork and Falsework The erection and removal of formwork and falsework shall be according to OPSS 919 and it shall be designed to retain the concrete and withstand the placement pressures. The formwork shall be placed to provide the specified cover to reinforcing steel or welded steel wire fabric, or both, as indicated in the Contract Documents. When this results in over-building of the existing concrete surface, a 1:1 slope shall be provided to meet the existing surface at the edges of the repair area. The perimeter of the formwork shall be sealed to be grout-tight. Vent holes shall be installed at the highest locations. July 2007 Pg. 10 of 19 SSP 109S50

11 Placing The method of placing concrete shall be according to OPSS 904, except that the form Notification of Placement of Structural Concrete shall not be required for concrete patches and concrete refacing Construction Joints Construction joints in concrete will be permitted only in the locations shown on the Contract Drawings and shall be according to OPSS Surface Finish The surface finish shall be according to OPSS Surface Tolerance Surface tolerance shall be according to OPSS Curing Unformed Surfaces The concrete shall be cured according to the requirements for Curing with Burlap and Water requirements specified in OPSS 904 for a minimum curing period of four days. The burlap and the moisture vapour barrier shall then be removed and the concrete permitted to air dry for not less than three days prior to any application of tack coat for waterproofing, where applicable Formed Surfaces General All exposed concrete surfaces of formed components shall be cured as specified in clause Concrete Patches, Formed Surface Concrete Patches, Form and Pump Curing shall be according to the following: a. If the formwork is left in place for four days or more, no additional curing will be required. b. Where the formwork is removed in less than four days, the concrete shall be cured as specified in clause for unformed surfaces, for the remainder of the four day curing period Concrete Refacing Concrete Refacing, Form and Pump Burlap and water shall be applied to the top of all exposed concrete surfaces, immediately after the finishing operation. The burlap shall be soaked for 24 hours prior to placing and shall be kept continuously wet by means of an operating soaker hose placed along the top of the component being refaced. The soaker hose shall be placed immediately after the concrete has set and its operation shall not cause fines to be washed out. July 2007 Pg. 11 of 19 SSP 109S50

12 Forms shall be removed within 16 to 24 hours of concrete placement, unless the Contractor is unable to remove the forms due to structural concerns. All concrete surfaces shall be immediately covered with wet burlap and moisture vapour barrier according OPSS 904 and shall be maintained in a moist condition for the remainder of the four day curing period Cold Weather Protection General The Contractor shall protect the concrete during cold weather. The protection system shall be designed for the worst conditions that can be reasonably anticipated from local weather records, forecasts, site conditions and past experience for the time period during which the protection is required. Regardless of ambient air temperature, overlays shall be moist cured with burlap and water at all times. During cold weather, burlap shall be prevented from freezing Control of Temperature During cold weather, the Contractor shall for a minimum period of seven days following concrete placement, monitor and control the temperature of the concrete to ensure that the concrete temperature does not fall below 10 o C. The Contractor shall take measures to ensure that the concrete temperature remains within the acceptable limits. The Contractor shall supply thermocouple wires and digital temperature indicators with an accuracy of +0.5 C to monitor the ambient air temperature and concrete temperature. The digital temperature indicators shall be left in place or one provided to the Contract Administrator to facilitate additional readings for verification purposes. Thermocouple wires shall be embedded near the concrete surface in a minimum of four locations for each day of concrete placement, as directed by the Contract Administrator. For cold weather conditions, protection of concrete shall at least be according to Table 1. July 2007 Pg. 12 of 19 SSP 109S50

13 TABLE 1 Minimum Cold Weather Protective Measures Anticipated Minimum Air Temperature ( o C) Protective Measure (Thickness of New Concrete) m < m <0.25 m +5 to 0 PM2 PM2 PM2-1 to 10 PM2 PM3 PM4-11 to 20 PM3 PM4 PM5 Less than 20 PM5 PM5 PM5 Maximum Allowable Drop in Concrete Temperature/24 h 15 C PM2 Protective Measure Cover concrete with insulation having an R-Value of 0.67**. PM3 Protective Measure Cover concrete with insulation having an R-Value of 1.33**. PM4 Protective Measure Cover concrete with insulation having an R-Value of 2.00**. PM5 Protective Measure House and heat as specified in Housing and Heating of OPSS 904. **Note: All R-Values are metric. The conversion factor from metric to imperial unit is: Metric R value x = Imperial R value Temperature Records The Contractor shall record the ambient air temperature and concrete temperature at a minimum frequency of once every four hours for the first 24 hours after concrete placement and then once every eight hours for the remainder of the protection period and during the removal of the cold weather protection and formwork. The Contract Administrator shall be provided the necessary access to the location and equipment to verify temperature readings Withdrawal of Protection The cold weather protection shall be gradually removed or reduced in such a manner that the maximum allowable drop of concrete temperature for each 24 h period as specified in Table 1 is not exceeded. The protection shall not be totally removed nor shall the concrete be fully exposed to the air until the average concrete temperature is within 10 o C of the air temperature. July 2007 Pg. 13 of 19 SSP 109S50

14 Field Sampling, Coring and Testing General Sampling and testing for air void system parameters and rapid chloride permeability shall be according to OPSS 1350 with the exception that where anode mesh is used, sampling and testing to determine rapid chloride permeability, and air void system parameters will not be required. Tensile bond strength testing will not be required for circular columns with spiral reinforcement and where anode mesh is used Air, Slump and Temperature The Contractor shall be responsible for all aspects of sampling and testing the plastic concrete for slump, air content and temperature according to OPSS 1350 and the results of these tests recorded. The minimum frequency of testing shall be one test from each load of concrete Tensile Bond Strength Lot Size A lot shall consist of the total quantity of concrete patches, concrete refacing or overlay in the Contract Documents. Each lot will be divided into sublots. Separate sublots are required for each overlay placement and for individual structures. Sublots for overlays shall be approximately equal in size and not greater than 300 m 2. For concrete patches and concrete refacing, sublots shall be approximately equal in size and not greater than 100 m 2. Patch areas shall not be combined with areas of concrete refacing for determining sublots. Testing will not be required on a structure when the total measured area of concrete patches on a structure is less than 20 m 2. Testing will not be required on a structure when the total area of concrete refacing on a structure is less than 20 m 2. The Contract Administrator will determine the sublot size after discussion with the Contractor and before any concrete is placed Tensile Bond Strength Requirements The Contractor shall be responsible for all aspects of sampling and testing of cores from overlays, concrete patches and concrete refacing, to determine tensile bond strength. The minimum tensile bond strength of concrete patches, concrete refacing and overlays shall be 1.0 MPa. The tensile bond strength testing shall be carried out by the Contractor, in the presence of the Contract Administrator, on three in-situ cores taken within one metre of each other for each sublot. The core locations will be randomly selected by the Contract Administrator. The Contractor shall locate reinforcing steel in the area prior to taking any cores to avoid cutting the reinforcing steel. The testing shall be carried out prior to the application of tack coat, where applicable, by technicians employed by a laboratory acceptable to the Ministry. The cores shall be obtained according to CSA A C, 100 mm in diameter and extend into the parent concrete to the depth specified in MTO LS-430. The testing shall be according to MTO LS-430 and shall be carried out when the concrete is 7 to 10 days of age. The equipment used to measure the tensile bond strength shall be equipped with a maximum load indicator. July 2007 Pg. 14 of 19 SSP 109S50

15 The Contractor shall ensure that the epoxy adhesive is cured according to the manufacturer s recommendations prior to carrying out the test. If failure occurs in the epoxy adhesive and the specified strength of 1.0 MPa has not been reached, the test shall be repeated within 300 mm of the original core location. Retesting is not required when the specified strength of 1.0 MPa has been achieved. After the tensile bond strength testing is completed, the cores shall be extracted for the full depth of the coring to demonstrate to the Contract Administrator that the depth of coring was adequate. All individual tensile bond strength results obtained by the Contractor shall be recorded on forms acceptable to the Ministry and forwarded to the Contract Administrator along with the average within four business days from the date of testing Filling of Core Holes Filling of core holes shall be according to OPSS Compressive Strength General Preparation, storage and transportation of cylinders to determine compressive strength shall be according to OPSS Early Strength Determination Testing for early strength determination shall be according to OPSS Remedial Work The Contractor shall notify the Contract Administrator in writing immediately if any of the defects or conditions listed in section are present in the Work, with an explanation of the cause and extent. These areas shall be repaired at the Contractor s expense. A proposal for the remedial work for the above defects and conditions shall be submitted to the Contract Administrator for review. The Contractor shall not proceed with repairs until approval of the proposal has been received. The Contractor shall treat cracks according to Table 2. Treatment shall not commence until the specified curing period has elapsed. Repair of cracks shall be according to OPSS 932 or the Contractor may submit an alternative proposal for repair to the Contract Administrator for review. The Contractor shall not proceed with application of tack coat for waterproofing until all remedial work has been accepted by the Contract Administrator. July 2007 Pg. 15 of 19 SSP 109S50

16 Overlays and Patches to be Waterproofed and Paved TABLE 2 - TREATMENT OF CRACKS Width of Crack* (mm) > 0.50 Exposed Overlays, Refacing and Patches > 0.30 Remedial Work Repair; or, if the linear measurement of cracks > 0.50 mm in width per m 2 is 2 m or greater, remove and replace concrete. Repair; or, if the linear measurement of cracks > 0.30 mm in width per m 2 is 2 m or greater, remove and replace concrete. * Width of crack is measured at the widest point of the crack (not average width of crack) Management of Excess Materials Excess materials resulting from the performance of the work under this specification shall be removed and managed as specified elsewhere in the Contract Documents Access to Work Areas, Work Platform and Scaffolding Adequate access shall be provided to facilitate placement of the concrete, inspection and measurement by the Contract Administrator Modification of Deck Drains Modification of deck drains shall be made prior to waterproofing the deck Drainage Tubes in Deck Installation of drainage tubes shall be made prior to waterproofing the deck QUALITY ASSURANCE Inspection After Curing The Contract Administrator will inspect the work to determine if the completed work contains any of the following defects: a. Areas of debonding. b. Honeycombed areas. c. Cracks Acceptance The Contract Administrator will reject all or a portion of the sublot based on: a. The presence of one or more of the defects identified in subsection b. Average tensile bond strength less than 0.6 MPa. c. Any work that does not conform to the requirements of this Special Provision. d. Any concrete that does not conform to the acceptance requirements of OPSS July 2007 Pg. 16 of 19 SSP 109S50

17 MEASUREMENT FOR PAYMENT General For all types of overlays there will be no measurement for the following: a. Concrete produced in excess of that required for the placing operation. b. Quantity of bonding agent. If the construction joint formed by the bulkhead is not according to clause and is deemed unacceptable by the Contract Administrator, the portion of overlay removed shall be deducted from the volume indicated on the delivery ticket. No measurement will be made for areas of new overlays, concrete patches and concrete refacing that were removed according to the requirements of subsection No measurement will be made for normal concrete and/or silica fume concrete required to patch, reface or overlay areas of concrete removal where the removal was not approved by the Contract Administrator Actual Measurement Place Concrete Overlay Place Silica Fume Concrete Overlay Measurement will be of the volume of concrete placed, including concrete placed in partial depth removals, in cubic metres by delivery ticket. Deductions will be made for concrete produced in excess of that required for the placing operation and for the portion of the overlay which is sawcut back and removed at the construction joint. The total volume will be calculated to the nearest cubic metre Concrete Patches, Formed Surface Concrete Patches, Unformed Surface Concrete Patches, Form and Pump Concrete Refacing Concrete Refacing, Form and Pump By Volume Measurement will be by the volume of concrete placed in cubic metres. The volumes will be calculated by multiplying each area to be patched by the average depth. Depths shall be taken on a grid system to best describe the profile at the particular area. The Contract Administrator, in the presence of the Contractor, shall take a minimum of three measurements for each removal area or 10 for every m 2, after concrete removal is completed by placing a straight edge across the removal area and measuring the depth from the straight edge to the concrete. The depths shall be measured and averaged to the nearest millimetre. No measurement shall be made for concrete required to fill localized areas behind the second layer of reinforcing steel. July 2007 Pg. 17 of 19 SSP 109S50

18 The total volume shall be calculated to the nearest 0.1 m Plan Quantity Measurement Modification of Deck Drains Measurement of the number of deck drains modified is by Plan Quantity, as may be revised by Adjusted Plan Quantity. The unit of measurement is each Drainage Tubes in Deck Measurement of the number of drainage tubes placed is by Plan Quantity, as may be revised by Adjusted Plan Quantity. The unit of measurement is each BASIS OF PAYMENT Modification of Deck Drains - Item Drainage Tubes in Deck - Item Place Concrete Overlay - Item Place Silica Fume Concrete Overlay - Item Finish and Cure Concrete Overlay - Item Finish and Cure Silica Fume Concrete Overlay - Item Concrete Patches, Formed Surface - Item Concrete Patches, Unformed Surface - Item Concrete Patches, Form and Pump Item Concrete Refacing - Item Concrete Refacing, Form and Pump - Item Payment at the Contract price for the above tender items shall be full compensation for all labour, equipment and material to do the work, subject to payment adjustments specified in the Contract Documents. Payment at the Contract price for the above tender item shall also include abrasive blast cleaning of the concrete surface for concrete patches and concrete refacing. Payment for abrasive blast cleaning of reinforcing steel and the concrete surface to receive an overlay will be administered under OPSS 929. When the Contract does not contain a separate tender item for providing access to the work, the Contract price for the concrete patching and concrete refacing items shall include full compensation for all labour, equipment and materials to do the work, including provision of access Payment Adjustment The payment reduction factor (Pr i ) for each sublot shall be calculated based on the following formula: Where: Pr i = 1.25 ( 1 B ) B = The average tensile bond strength (MPa) for each sublot. (For the purpose of calculating the payment reduction, a value of 1.0 MPa shall be used for B when the average tensile bond strength is greater than 1.0 MPa.) i = Sublot number July 2007 Pg. 18 of 19 SSP 109S50

19 The payment reduction (Pr) for the lot is calculated by the equation: Pr = Tender Unit Price x [(Pr 1 x LQ 1 ) + (Pr 2 x LQ 2 )... (Pr n x LQ n )] Where: Pr i = Payment reduction factor for sublot i LQ i = Quantity for sublot i (m 3 ) n = The total number of sublots For the purpose of calculating the payment reduction for concrete overlays, the Pr shall be applied to both Place Concrete Overlay and Finish and Cure Concrete Overlay items. For the purpose of calculating the payment reduction for silica fume concrete overlays, the Pr shall be applied to both Place Silica Fume Concrete Overlay and Finish and Cure Silica Fume Concrete Overlays items. July 2007 Pg. 19 of 19 SSP 109S50