390 Page 245390 CONCRETE SPALL REPAIR
390.1DESCRIPTION
This work consists of removal of sealant from transverse contraction joints, repair of spalled areas, sawing, cleaning, and resealing joints.
390.2MATERIALS
A.Bonding Mortar for Concrete Patches: 1.Cement: Cement will conform to Section 750. 2.Water: Water will conform to Section 790. 3.Sand: Sand will conform to Section 810.1 . 4.Proportioning: Bonding mortar will be mixed in the following proportions by volume: 2 parts Portland cement. 1 part sand. Mix with only enough water to form a thick creamy consistency. B.Concrete Patch Material: Concrete patching material will be one of the following and approved by the Department’s Concrete Engineer: 1.Type I: A packaged, dry, rapid-hardening mortar conforming to the requirements of ASTM C 928, Type R-3 containing no chloride ions. A magnesium or phosphate based product will not be allowed. If extender aggregate is added, the extender aggregate will conform to Section 820. 2.Type II: A packaged, dry, rapid-hardening concrete conforming to the requirements of ASTM C 928, Type R-3 containing no chloride ions. A magnesium or phosphate base product will not be allowed. If extender aggregate is added, the extender aggregate will conform to Section 820. 3.Type III: A dry, bagged air entrained concrete patching material (known as 3U58M) meeting the following requirements: a.Materials: 1)Cement: Cement will conform to Section 750. 2)Coarse Aggregate: Coarse aggregate will conform to Section 820 except the gradation will conform to the gradation specified in Section 390.2 B.3.b . 3)Fine Aggregate: Fine aggregate will conform to Section 800 for Class M concrete except the gradation will conform to the gradation specified in Section 390.2 B.3.b . 390 Page 2464)Air Entraining Admixture: Air entraining admixture will be dry and blended in the bag. 5)Water: Water added at the time of batching will conform to Section 790. 6)Other Admixtures: Other admixtures, if used, will conform to Section 752 and may be dry blended in the bag or added at the time of batching. b.Gradation : The coarse and fine aggregate will be blended at a 50-50 ratio by volume to meet the following gradation: 3U58M Gradation Requirements Sieve Size Percent Passing 3/8 inch 100 #4 80-100 #8 40-80 #16 25-50 #30 15-35 #50 0-18 #100 0-8 #200 0-2.3 c.Mix Proportions: Proportion the mix in accordance with the following Table per 75 pound bag of dry mix. If other sizes of bags are used, they will contain the same proportioning Mix Proportions Material Weight, pounds Type I Cement 17.8 Coarse Aggregate 28.3 Fine Aggregate 28.9 d.Blending: Provide a blending device meeting the following charact eristics and requirements: 1)Capable of producing the required mix proportions within ±2%, 2)Contains a proportioning device equipped with a warning device to indicate when the system is out of tolera nce, 3)Capable of stopping the flow of cement to allow sampling of the blended coarse and fine aggregate, 4)Designed to allow cement and aggregate to run out separat ely for checking material weights and ensuring that the blending proportions meet mix requirements. Before blending with the cement, dry the coarse and fine aggregates as approved by the Enginee r. Blend the cement and aggregate before bagging the mix. 390 Page 247e.Bags and Batch Identification: Provide moisture and tear resistant bags. Print the following on the bags: 1)The Phrase “3U58M Concrete Patch Mix” 2)Weig ht of the bag in pounds 3)Mix date 4)The instructions for mixing into concrete C.Epoxy Resin Mortar : 1.Sand: Sand will conform to Section 810.2 . 2.Epoxy Resin: The epoxy resin adhesive will conform to AASHTO M 235, Type III, Grade 2. 3.Proportioning: Proportioning will be as recommended by the manufacturer. D.Sealant: Silicone or hot pour sealant as detailed in the plans will conform to Section 870.
390.3CONSTRUCTION REQUIREMENTS
A.General: Spall repair locations will be marked in the field by the Engineer. Joints on which seal removal or spall repair has begun will be completed and sealed during the same construction season. Spall repair and seal replacement will only be permitted between May 1 and October 15, inclusive unless the Contractor has received written permission from the Region Engineer to continue later than October 15. Sealing operations will only be permitted when the air and pavement surface temperatures are 40°F or greater and rising. The pavement will be dry before starting the concrete patch. In place sealant will be removed from transverse joints prior to placing the concrete patch. Spalled areas 1/2 inch deep or less at the joint will not need repair. When both Type A and Type B spalls are shown on the plans, Type A spalls are over 0.2 foot wide and Type B are spalls 0.2 foot wide or less but greater than 0.06 foot wide. Spalls less than 0.06 foot wide will be filled with joint sealant. B.Type A Spalls: Edges of areas to be repaired will be sawed to a depth necessary, minimum of 1½ inch, to ensure the area can be chipped down to sound concrete. Jack hammers of 30 pounds. maximum, and chipping hammers of 15 pounds. maximum will be used. After sawing, the vertical edges will be removed by chipping. The bottom of chipped areas will be left rough to obtain a good bond between the patch and the old concrete. The area will then be sandblasted, and the sand blown from the joint and the patch area. Partially exposed dowel bars will be coated or covered with an approved bond breaker. Improperly aligned or positioned bars will be removed. Prior to placing the patch, the joint will be formed to a width equal to the current opening. The area will be chipped to a uniform depth, to facilitate forming to the depth of removal. Forming material will be foam core board or other stiff material capable of standing without deflection. The forming material will be one unit for the length of the spall repair area. 390 Page 248The concrete patch material will be mixed and placed in accordance with the manufacturer’s technical data sheet. The Contractor will provide a manufacturer’s technical data sheet to the Engineer prior to performing the work. At placement, the patch material will be between 50F and 90F and will be maintained above 45F until 3,000 psi has been obtained. Traffic will not be permitted over the area until the repair material has reached 3,000 psi. Compressive strength results that do not meet the minimum requirement will be evaluated by the Department’s Concrete Engineer to determine if the concrete is structurally adequate. If the Contractor disputes the accuracy of the results of the compressive strength testing, the Contractor must submit a written proposal for how the in place strength will be evaluated to the Department’s Concrete Engineer within 5 calendar days of the Department notifying the Contractor of the deviation. The proposal must be successfully reviewed by the Department’s Concrete Engineer before the Contractor may proceed with any in place strength evaluation. Upon removal of the forming material, the joint will be sawed, cleaned, and sealed. Specific installation details will conform to the following based on the type of concrete patch material used: 1.Type I & II (packaged, dry, rapid hardening mortar or concrete – ASTM C928 Type R-3) If a bonding agent or bonding mortar is recommended by the manufacturer’s technical data sheet, the bonding agent will be in accordance with the manufacturer’s guidelines. The patch will be screeded from existing pavement to existing pavement. The top surface will be trowel finished from middle of patch to existing concrete. Any saw cuts that extend beyond the patch perimeter will be filled with patching material. The surfaces of the patch will be given a broomed finish. Patched areas will be wet cured with curing blankets and white polyethylene sheeting for a minimum of 8 hours then sprayed with curing compound at a minimum rate of 1 gallon per 150 square feet. 2.Type III (bagged air entrained concrete patching material - 3U18) A layer of bonding mortar will be scrubbed into and over the surfaces to be patched immediately prior to patch placement. Excess grout must not pool in the low areas. The patch will be placed before the bonding mortar dries and will be consolidated by vibration. The patch will be screeded from existing pavement to existing pavement. The top surface will be trowel finished from middle of patch to existing concrete. After screeding and finishing, the same bonding grout will be used to paint the edges of the repair. Any saw cuts that extend beyond the patch perimeter will be filled with patching material and must also have the surface painted with bonding grout. 390 Page 249The surfaces of the patch will be given a broomed finish. The patched area will be sprayed with curing compound at a minimum rate of 1 gallon per 150 square feet. An additional coat of curing compound will be applied after 20 minutes but less than 1 hour after the first application. C.Type B Spalls: The spalled concrete will be removed, and the areas chipped down to sound concrete. The resulting areas will be left rough to obtain a good bond between patch and concrete. The area will then be sandblasted, and the joint formed as specified for Type A spalls. The entire area will be given a coat of straight epoxy resin (without aggregates). Epoxy resin mortar will immediately be tamped in place and troweled off. Placement of epoxy will be permitted only within the temperature range recommended in AASHTO M 235, for the class of epoxy used. Form removal, joint sawing, and traffic over the patch area will not be permitted for 8 hours after placement. D.Saw and Seal Joints: Transverse joints will be sawed to the uniform width and depth specified. For silicone sealant, the Contractor will have backer rod available for variable width joints up to 1½ inches wide. Prior to sealing, the joints will be cleaned in conformance with Section 380.3 P. Once cleaning operations begin, traffic will not be permitted over repair areas until joints are sealed and seal material has cured.
390.4METHOD OF MEASUREMENT
A.Saw and Seal Joints: Saw and seal joints will be measured to the nearest foot. The areas that have spall repairs will not be measured. B.Repair of Type A Spalls: Repair of Type A spalls will be measured to the nearest 0.1 square foot. Surface measurements will be taken to the nearest 0.1 foot. C.Repair of Type B Spalls: Repair of Type B spalls will be measured to the nearest 0.1 foot or to the nearest 0.1 square foot, as shown on the plans.
390.5BASIS OF PAYMENT
A.Saw and Seal Joints: Saw and seal joints will be paid for at the contract unit price per foot. Payment will be full compensation for removal of old sealant, cleaning, and resealing the joints. B.Repair of Type A Spalls: Repair of Type A spalls will be paid for at the contract unit price per square foot. Payment will be full compensation for sawing, sealing, materials, labor, equipment, and incidentals required. C.Repair of Type B Spalls: Repair of Type B spalls will be paid for at the contract unit price per foot or to the nearest square foot, as shown on the plans. Payment will be full compensation for sawing, sealing, materials, labor, equipment, and all incidentals required. 391 Page 250391 UNDERSEALING
391.1DESCRIPTION
This work consists of filling existing voids under PCC pavement by drilling injection holes and pumping a cement/fly ash grout under the pavement slab.
391.2MATERIALS
A.Design Mix: The design mix for grout will conform to the following proportions by absolute volume: 1 Part Portland cement 3 Parts fly ash Water to achieve the specified fluidity Fluidity of the grout when measured by a flow cone in accordance with ASTM C939 will have a time of efflux between 9 and 15 seconds. The Contractor will submit for approval materials proposed for use. The submittal will include mill certification for cement, physical and chemical analysis for fly ash, and tests of the grout slurry by a Department approved testing laboratory. Tests will show one-, three-, and seven-day strengths, flow cone times, shrinkage and expansion observed, and time of initial set. The seven-day strength will be at least 600 psi as measured in accordance with ASTM C942. As an alternate, standard 6 inch diameter by 12 inch high water tight concrete cylinder molds may be used to determine seven day strength. When the cylinder molds are used, the strength will be 700 psi minimum. Compressive strength results that do not meet the minimum requirement will be evaluated by the Department’s Concrete Engineer to determine if the grout is structurally adequate. If the Contractor disputes the accuracy of the results of the compressive strength testing, the Contractor must submit a written proposal for how the in place strength will be evaluated to the Department’s Concrete Engineer within 5 calendar days of the Department notifying the Contractor of the deviation. The proposal must be successfully reviewed by the Department’s Concrete Engineer before the Contractor may proceed with any in place strength evaluation. Alternate design mixes for the grout may be submitted to the Engineer for approval. B.Portland Cement: Type I or Type II cement is required. The cement will meet the requirements of C.Fly Ash: Fly ash will conform to Section 753. D.Water: Water will conform to Section 790.
391.3CONSTRUCTION REQUIREMENTS
A.General: The Contractor, or subcontractor performing the undersealing, will have prior experience with undersealing operations and will have personnel on the project with expertise in undersealing. Prior to awarding the contract, the Department may require the