511Concrete Structures

511.1 Description

This Work consists of construc ting concrete box Culverts, headw alls, retaining walls, abutments, bents, piers, slabs, gi rders, and Incidental Structu res requiring the use of concrete, except pre-stressed members.

511.2 Materials

When waterproofing is required by the Contract but a type is no t specified, either fluid- applied waterproofing or sheet membrane waterproofing shall be used.

511.2.1 Portland Cement Concrete

The Contractor shall use concrete mixes that have been designed in accordance with Section 509, “Portland Cement Concrete Mix Designs” and approve d for use on NMDOT Projects by the State Materials Bureau for the freeze/thaw risk zone in which the Project is located. A higher risk zone c oncrete may be substituted.

511.2.1 1 Concrete Surface Finishing Materials

For Class 2 Surface Finish, the Contractor may use a thin morta r composed of one (1) part cement and four (4) parts sand passing the No. 16 sieve. The cement used in the thin mortar shall be of the same type and source as that used in fre shly placed concrete. Alternatively, the Contractor may use a prepackaged, polymer mo dified mortar, designed specifically for concrete surface finishing with a minimum 28 d ay compressive strength of 2,000 psi per ASTM C109.

511.2.2 Steel Reinforcing

The Contractor shall provide steel reinforcement in accordance with Section 540, “Steel Reinforcement.”

511.2.3 Bonding Agent

The Contractor shall use a bonding agent that meets the requir ements of ASTM C1059, Type II or C-881 Type V.

511.2.4 Form Release Agent

The Contractor may use form release agents at their discretion . Compatibility must be confirmed in a letter from the Manufacturer of subsequent surfa ce treatments including but not limited to penetrating water repellent treatment, stains, and/o r paints. If compatibility cannot be confirmed, form release residue shall be removed per the sur face preparation recommendations of the manufacturer of the subsequent product. When integrally colored concrete is used, the Contractor shall use form release agents that are non-staining and minimi ze surface imperfections of con crete.

511.2.5 Liquid Applied Evaporation Reducers

Unless otherwise specified in the Contract documents, the Cont ractor may utilize liquid- applied evaporation reducers to reduce the effects of excessive rate of evaporation at the Section 511: Concrete Structures Page 352 surface of plastic concrete. Evaporation reducers shall be com mercially available water-based compounds that are specifically designed to form a thin monomol ecular film to reduce rapid moisture loss from the concrete surface prior to curing. The p roduct shall be certified to have no adverse effects on the cement hydration process or the concr ete and that it reduces surface moisture evaporation from the concrete when performing concrete operations in direct sun, wind, high temperatures, and/or low relative humidity.

511.2.6 Curing Materials

511.2.6 1 Liquid Membrane Forming Compounds

The Contractor shall use Type 1-D or Type 2 liquid membrane-fo rming concrete curing compounds that comply with ASTM C 309. When integrally colored concrete is used, the Contractor shall use only curing compounds specifically recommended for use with colored concret e and in accordance with ASTM C309 Type 1.

511.2.6 2 Linseed Oil Emulsion

The Contractor shall not use linseed oil emulsion-curing agent .

511.2.6 3 Sheet Materials for Curing Concrete

The Contractor shall use concrete curing sheet Materials in ac cordance with AASHTO M 171. The Department will only allow the white reflective type.

511.2.7 Joint Materials

The Contractor shall provide joint filler Material in accordanc e with AASHTO M213 or AASHTO M153 Type I or IV (no cork). The Contractor shall provide liquid-applied joint sealant in ac cordance with Section 452, “Sealing and Resealing Concrete Pavement Joints” at non-Bridge joint locations.

511.2.8 Extruded Polystyrene

The Contractor shall provide extruded polystyrene that complie s with ASTM C578 Types X or XII (15 psi), Type IV (25 psi), or Type VII (60 psi). If strength is not shown in the contract, the Contractor shall use Type IV (25 psi). Extruded or expande d polystyrene may be used interchangeably.

511.2.9 Tear–Web Waterstop

Waterstop at the joint between abutment cap and abutment diaphr agm shall be tear-web waterstop. The Contractor shall provide a product that meets t he requirements of Table

511.2 9:1, “Tear–Web Waterstop Requirements.”

TABLE 511.2.9:1 Tear–Web Waterstop Requirements Typical Properties ASTM Method Minimum Value Tear–Web Waterstop Requirements Typical Properties ASTM Method Minimum Value Water Absorption D-570 0.10% Tear Resistance, lb/in D-624 225 Specific Gravity, (+/-0.05) D-792 1.38 Hardness, Shore A D-2240 80 (+/-5, 10 sec. delay) Tensile, psi D-638, Type IV 2000 Elongation % D-638, Type IV 350 Low Temperature Brittleness @ - 35° F D-746 No Failure Stiffness in Flexure, psi D-747 600 Accelerated Extraction, USACE CRD-C572 Tensile, psi D-638, Type IV 1600 Elongation, % D-638, Type IV 300 Effect of Alkali, USACE CRD-C572 Weight Change, % ----- +0.25%, -0.10% Change in Hardness, Shore A D-2240 +/-5 points

511.2.10 Sheet Membrane Waterproofing

When specified in the Contract documents, the Contractor shall install waterproof membrane Materials. For this application, the Contractor shall provide flexible, sheet membrane waterproofing Material that is a minimum 50 mil thickn ess. Compatible surface primers, adhesives and flashings shall be used as recommended b y the manufacturer’s application instruction. The Material shall meet the requireme nts of Table 511.2.10:1, “Sheet Membrane Waterproofing Requirements.” TABLE 511.2.10:1 Sheet Membrane Waterproofing Requirements Typical Properties ASTM Method Value Water Vapor Permeance ASTM E96 0.05 perms max Elongation ASTM D412 300% min Tensile Strength ASTM D412 300 psi min Peel Strength ASTM D903 8 lbs/in min Puncture Resistance ASTM E154 45 lbf min

511.2.11 Fluid-Applied Waterproofing

When specified in the Contract documents, the Contractor shall install cold, fluid-applied waterproof membrane Materials on concrete walls prior to backfi ll. For this application, the Contractor shall provide seam less rubberized asphalt membrane a t a minimum thickness of 30 mils. Compatible surface primers, and joint, crack, and cor ner treatments shall be used as recommended by the manufacturer’s application instruction. The Material shall meet the Section 511: Concrete Structures Page 354 requirements of Table 511.2.11:1, “ Fluid-Applied Waterproofing Requirements.” TABLE 511.2.11:1 Fluid-Applied Waterproofing Requirements Typical Properties ASTM Method Value Solids by Weight ASTM D1644 60% min Elongation ASTM D412 300% min Water Vapor Permeance ASTM E96 0.1 perms max Hardness ASTM C661 60 max

511.2.12 Swellable Hydrophilic Waterstop

Swellable hydrophilic waterstop shall meet the requirements of ASTM D-71, ASTM D-6, and ASTM D-217. The following properties will apply: 1. Specific gravity — ASTM D71: 1.35; 2. Hydrocarbon content — ASTM D4: 47%; 3. Volatile matter — ASTM D6: one percent (1%); 4. Penetration cone in accordance with ASTM D217 at 77 degrees F (25 degrees C): 40 mm; and 5. Service temperature range: -30 to 180 degrees F (-34 to 82 degrees C).

511.3 Construction Requirements

511.3.1 Concrete Placement

Concrete shall be placed and tested for compliance with the Pro ject Specifications in accordance with Section 510, “Portland Cement Concrete.”

511.3.2 Temporary Works and Falsework

511.3.2 1 Temporary Works

The Contractor shall perform temporary Works in accordance with the current edition of the AASHTO Guide Design Specificat ion for Bridge Temporary Work s and the AASHTO Construction Handbook for Bridge Temporary Works. Although the document contains “Gu ide Design Specifications,” the Contractor shall consider them to have the same i mportance and standing as a cod e or a Specification. If the content of the collaboration documents appears permissive with words such as “should,” “could,” “may,” etc., the Contractor shall consider the content to be a requirement unless otherwise approved by the State Bridge Engineer. In the event of a conflict between a referenced code and this Specification, this Specification will take precedence.

511.3.2 2 Falsework and Falsework Foundations

The Contractor shall construct Structure in accordance with Sec tion 511, “Concrete Structures,” and Section 512, “Superstructure Concrete”, as app licable. Section 511: Concrete Structures Page 355 The Contractor shall design, construct, and maintain falsework and falsework foundation to provide the required strength and rigidity, and to support l oads without settlement. The Contractor shall have a professional Engineer licensed in the S tate of New Mexico design the falsework and its foundation. The design of the falsework and foundation will be required if one (1) or more of the following conditions apply: 1. If the height of the Structure is greater than ten (10) ft ( excluding concrete Culverts with bottom slabs); 2. Where the supported span is greater than 15 ft; or 3. Where traffic, other than workmen involved in constructing t he Structure, will travel under the falsework. The Contractor shall place the falsework on an adequate foundat ion. The maximum foundation bearing pressure is 2,000 pounds per square foot unl ess a Geotechnical investigation indicates a higher value can be used. The Contra ctor shall provide methods for measuring settlement or movement of falsework and forms under l oad. If falsework shows settlement greater than 3/8 inch at the vertical supports, the Contractor shall stop the Work and correct the settlement or movement. If pilings are used for falsework, the Contractor shall pull or cut off falsework pilings. The Contractor shall ensure the cut-off elevations are one (1) ft b elow the low water level, natural ground, or bottom of proposed channel. If required, the Contractor shall submit Plans for falsework to the State Bridge Engineer for approval. The Contractor shall submit proposed changes to existing Structures required for maintenance of traffic to the Project Manager for approval. 30 Days shall be allowed for the initial review. 15 additional Days shall be allowed for ea ch resubmittal.

511.3.3 Form Construction

The Contractor shall make forms mortar tight and sufficiently r igid to prevent deformation due to the pressure of the concre te and other loads Incidental to the construction operations, including vibration. The Contractor shall construct and mainta in forms to prevent the joints from opening. The Contractor shall construct and maintain form s used on surfaces in public view such that the finished c oncrete surface will be smooth and of uniform color and texture. The Contractor shall remove loo se dirt, laitance, and miscellan eous debris from the bottom of the forms before placing concrete. The Contractor shall fillet forms and chamfer them 3/4 inch, un less required otherwise in the Contract, and give them a bevel or draft for easy removal o f projections such as girders and copings.

511.3.3 1 Form Lumber

The Contractor shall use lumber that is planed on at least one (1) side and the two (2) edges for exposed concrete surfaces. The Contractor shall plac e the planed face so that it will be the formed surface for the concrete being placed.

511.3.3 2 Metal Ties

The Contractor shall construct metal ties and anchorages withi n the forms to permit the removal of a portion of the tie connections without damaging th e concrete, and provide at least 1/2 inch depth of cover from the concrete surface. Section 511: Concrete Structures Page 356 511.3.3.3 Surface Treatment of Forms The Contractor shall ensure that forms have been properly wett ed before placing concrete. The Contractor shall use form release agents at their discreti on before placing reinforcing steel. The Contractor shall not use form release agents that a dhere to or discolor the concrete.

511.3.3 4 Metal Forms

The Contractor shall provide metal forms thick enough to preve nt bending and maintain their shape. The Contractor sha ll use countersunk bolts and ri vet heads. The Contractor shall use clamps, pins, and other conn ecting devices designed to hold forms rigidly together and for removal without damaging the concrete. The Contractor shall us e metal forms that have a smooth surface and line up properly. The Contractor may use metal forms that remain part of the Str ucture in accordance with the Contract or as approved by the State Bridge Engineer. The Contractor shall use permanent steel Bridge deck forms in accordance with Section 51 2.3.4.1, “Permanent Steel Deck Forms.”

511.3.3 5 Reuse of Forms

The Contractor shall continuously maintain the shape, strength , rigidity, water tightness, and surface smoothness of reused forms. The Contractor shall r esize warped or bulged lumber before reusing it.

511.3.4 Temperature and Weather Limitations

The Contractor shall keep the concrete mixture temperature bet ween 50 °F to 90 °F at the time of placement.

511.3.4 1 Cold Weather Concrete

The Contractor shall place cold weather concrete in accordance with ACI 306, “ Cold Weather Concreting .” If air temperatures are likely to fall below 40 °F during the placement or curing periods, the Contractor shall submit a cold weather concreting and curin g plan to the Project Manager for approval by the State Concrete Engineer before concrete pla cement. The Contractor shall allow 14 Days for review. The Contractor shall ensure that the Plan details the methods and Equipment to maintain the require d concrete temperatures over t he entire concrete pour area. Information submitted will include, but not be limited to: 1. Whether or not outside heating sources will be used (and how the exhaust will be vented away from the fresh concrete); 2. Whether or not the rate of surface evaporation is expected t o exceed the limitations detailed in Section 511.3.4.3, “Rate of Evaporation Limitations ” and measures to be taken; 3. What the target mix temperature will be; 4. How the concrete will be prot ected from the ambient conditio ns; 5. Curing methods to be used during and following the protectio n period; Section 511: Concrete Structures Page 357 6. How soon after the placement the protection from the ambient conditions will be implemented; 7. Who will be responsible for ins uring that the proper protect ion from the environment is properly implemented; 8. How the actual temperature of the concrete will be monitored ; a. How often will this be checked; b. Who will do the checking; 9. What actions will be taken if the temperatures fall below th e target points; 10. Who will be responsible for ta king the necessary actions; a nd 11. Who the contact will be if Department Personnel need to tra nsmit notices or information about the cold weather conditions. Review and Acceptance of the Cold Weather Concreting and Curin g Plan shall not relieve the Contractor from its obligation to perform the Work and provide Materials in strict conformance with the Contract. The Contractor shall not place concrete directly onto any surf ace that is less than 40 °F unless otherwise approved by the Project Manager. The Contract or shall not place concrete on frozen ground. If placing concrete at or below air temperatures of 35 °F, the Contractor shall provide suitable enclosures and heating devices. The Contractor shall vent exhaust from combustion type heating devices outside the placing area so that the exhau st fumes cannot come in contact with the freshly placed concrete. The Contractor shall ensure the concrete surface temperatures never fall below 45 °F during placement and the first th ree (3) Days after placing. T he Contractor shall not let the surface temperature fall below 40 °F during the next four (4) D ays after the initial three (3) Day curing period, or until the in-place strength determined by the Maturity Method , in accordance with Section 510.3.5.2, “In-Place Concrete Strength Measurement s” indicates that 75% of the design strength is achieved. The Contractor shall monitor the minimum concrete temperatures at various locations including edges and corners of slabs or other Structures, and c heck immediately before placing insulating Material over the concrete. If heating the aggregates or water, the Contractor shall use h eating methods and Equipment that can heat the Material uniformly. The Contractor shall not heat the Materials to more than 110 °F. During the heating or mixing process, the Co ntractor shall not add cement to water and aggregate combinations that are hotter than 90 °F.

511.3.4 2 Hot Weather Concrete

The Contractor shall place hot weather concrete in accordance with ACI 305, “ Hot Weather Concreting.” Hot weather is any combination of the following conditions tha t tends to impair the quality of freshly mixed or hardened concrete by accelerating the rate of moisture loss and rate of cement hydration or otherwise c ausing detrimental results: hig h ambient temperature; high concrete temperature; low relat ive humidity; wind speed; or sol ar radiation. The Contractor shall estimate the rate of evaporation at the s urface of the concrete per Section 511: Concrete Structures Page 358 Section 511.3.4.3, “Rate of Evaporation Limitations.” If the r ate of evaporation is anticipated to be greater than 0.2 lb per sq ft per hour, the Contractor shall submit a hot weather concreting and curing Plan to the Project Manager for approval by the Stat e Concrete Engineer before concrete placement. The Contractor shall allow 14 Days for rev iew. The Contractor’s Hot Weather Concreting and Curing Plan shall include measures that shall be taken by the Contractor at their expense and maintaine d to the satisfaction of the Project Manager to reduce the rate of evaporation during initia l cure to within the specified rate. The methods can include but not be limited to following: 1. Erect windbreaks to reduce the wind velocity over the concre te surface; 2. Place concrete during nighttime or early morning hours; 3. Use cool aggregate and mixing wa ter to lower the fresh concr ete temperature; 4. Increase the relative humidity at the site with a fog spray; and/or 5. Apply a liquid-applied evaporation reducer. Review and Acceptance of the Hot Weather Concreting and Curing Plan shall not relieve the Contractor from its obligation to perform the Work and prov ide Materials in strict conformance with the Contract.

511.3.4 3 Rate of Evaporation Limitations

The “Rate of Evaporation Limita tions” are detailed in ACI 305 – Hot Weather Concrete. These procedures lessen the potent ial of plastic-shrinkage crac king in concrete. The “Rate of Evaporation Limitations” apply to Bridge decks, approach slabs, CBC (top and bottom slabs), slipped formed concrete Structures, all PCCP and structural sho tcrete. ACI 308 – Guide to Curing Concrete emphasizes that the rate of evaporation limitat ions can be exceeded in both cold and hot weather and must be addressed in both conditions. The Contractor shall determine the anticipated rate of evapora tion of surface moisture from the concrete by utilizing Fi gure 511.3.4.3:1, “Surface Eva poration from Concrete.” The Contractor shall not place concrete if the anticipated rate of evaporation exceeds 0.20 lb per square foot per hour at the site over any ten (10) minute perio d, unless measures are taken to prevent excessive moisture loss f rom the surface of the concret e during initial curing. See Section 511.3.4.2, “Hot Weather Concrete” for Acceptable measur es. These measures must be detailed in the Cold Weather Concrete Plan per Section 511.3 .4.1, “Cold Weather Concrete” or the Hot Weather Concrete Plan per Section 511.3.4. 2, “Hot Weather Concrete.” During the concrete placement, the wind speed, relative humidi ty and ambient air temperature shall be collected via a computerized weather stati on that shall be provided and retained by the Contractor. The weather station shall be an au tomated system that does not require any human support or effort after its initial set-up. The Contractor shall record readings at minimum five (5) mi nute intervals until the final c uring system has been physically applied. Copies of these readings shall be submitted to the Pr oject Manager within 24 hours of the placement. Measurements to determine the Surface Evapor ation from the Concrete shall be taken at a height of approximately five (5) feet above the deck for relative humidity and ambient air temperature, and between a height of 20 inches and five (5) feet for wind speed. For concrete placements that are smaller than ten (10) cubic y ards, a handheld anemometer may be used in lieu of a weather station. The handh eld anemometer shall be capable of measuring wind speed, humidity and air temperature; and shall be supplied and retained by the Contractor. Figure 511.3.4.3:1 Surface Evaporation from Concrete (reference ACI 305) To use this chart: 1. Enter with air temperature, move up to relative humidity 2. Move right to concrete temperature 3. Move down to wind velocity 4. Move left; Read approximate rate of evaporation 511.3.4.3.1 Wind Break If a wind break is used, the wind break shall be a minimum hei ght of eight (8) ft - zero

511.3.4 3.2 Fogging System

If a fogging system is used, a water fog shall be continuously applied over the surface of the freshly placed concrete in such a manner that the entire su rface is kept at a relative humidity of 90% or greater and the surface of concrete is kept at an evaporation potential of 0.15 pound/square foot/hour or less, as determined from Figure 511.3.4.3:1, “Surface Evaporation from Concrete.” The evaporation potential shall be determined prior to fogging and outside the wind protection, and continuously monitored wit h evaporation potential measurements taken and recorded at least once every five (5) mi n throughout the entire placement, and continuing until the concrete curing system has been completely installed. If a wind break and/or fogging are being used, the Contractor shall obtain these readings from the protected area at a height of approximately five (5) feet above the protected concrete. The area to be fogged shall be the entire area of the freshly placed concrete, which has not had the final finish applied. This fog shall be delivered through a network of nozzles, which are properly spaced to provide a uniform fog at the surfa ce of the concrete. The nozzles used shall be of the type, which atomizes the water so that there are no visually discernible droplets of water. The area of coverage from each nozzle shall overlap all adjacent nozzle coverage by at least one (1) ft. It shall be d emonstrated prior to the placement of the concrete that the intended system is capable o f delivering the required fogging environment for at least twice the anticipated required time. The Contractor shall not finish or otherwise mix any of the fogging water into the fresh concrete. The intended system must be properly field tested, and approve d by the State Materials Bureau before being used on any S uperstructure concrete. Foggi ng shall continue until the surface is treated with an approved curing method.

511.3.4 3.3 Liquid Applied Evaporation Reducers

If a liquid-applied evaporation re ducer is used, it shall be s elected from the Departments Approved Products list and must be applied in strict accordance with manufacturer’s application instructions. Liquid applied evaporation redu cers are not curing compounds a nd are not finishing aids. Liquid applied evaporation reducer s are to be used to reduce su rface evaporation during the initial cure of concrete. Initial cure of concrete typically o ccurs up to and including bull-floating. Multiple applications of liquid applied evaporation reducer may be required, reference manufacturer’s application instructions. Upon commencing surface finishi ng (beyond bull-floating), furt her application of liquid evaporation reducers shall not be allowed (liquid evaporation r educers cannot be used as finishing-aids). The Contractor shall cure concrete after surf ace finishing in accordance with

511.3.5 Concrete Placement

Concrete shall be placed and tested for compliance with the Pro ject Specifications in accordance with Section 510, “Portland Cement Concrete.” The Contractor shall not place concrete until the Project Mana ger approves the reinforcing steel and forms. The Contractor shall ensure that forms are clean and free of rust, grease, and other Deleterious Mat erial immediately before placi ng the concrete. The Contractor shall remove wooden form spacers immediately before placing concrete in that area. The Contractor shall vibrate the concrete during placement to force the coarse aggregate from external surfaces and to bring mortar against the forms to produce a smooth finish significantly free of water, air pockets, and honeycombs. The Contractor shall place concrete in girders, walls, and oth er similar Structures in horizontal layers. The Contractor shall ensure that the concre te is not too thick for the vibrator to consolidate and merge it with the previous layer. The Contr actor shall not pour concrete layers deeper than two (2) ft. The Contractor shall not place concrete faster than the rate u sed for the design of the forms. The Contractor shall adjust the rate for the temperatur e of the concrete being placed.

511.3.5 1 Chutes and Troughs

The Contractor shall avoid segregation of the Materials and th e displacement of the reinforcement when placing the concrete. The Contractor shall use metal or metal-lined open troughs and chutes; the Contractor shall not use aluminum. All tools used for the moving and/or spreading of the concrete shall be square pointed tools. The Contractor shall not use round nose shovels and spreading tools. Where the Contract requires steep slopes, the Contractor shall equip the chutes with baffle boards or use short lengths that reverse the direction o f movement. The Contractor shall keep chut es, troughs, and pipes clean and free of hardened concrete by thoroughly flushing with water after each pour. Th e Contractor shall discharge the water used for flushing away from the placed concrete. The Contractor shall not allow concrete to free fall for more than three (3) ft. For CBC walls and retaining walls that are less than or equal to ten (1 0) inches thick, maximum free fall heights shall not apply. For CBC walls and retaining walls gre ater than ten (10) inch thick, concrete may have a free fall of less than nine (9) ft. The Contractor shall fill each part of the form by placing the concrete as close to the final position as possible. The Contractor shall vibrate the concret e during placement to force the coarse aggregate back from the forms and around the reinforceme nt without displacing the bars. After the concrete's initial set, the Contractor shall n ot jar the forms or place strain on the ends of projecting reinforcement. 511.3.5.2 Concrete Pumping If placing concrete by pumping, the Contractor shall install p umping Equipment so that vibrations resulting from the op eration do not damage the concr ete being placed. The Contractor shall obtain Project Manager approval before using c oncrete pumping Equipment. Before placing the concrete, the Contractor shall clean the Eq uipment thoroughly. The Contractor shall operate the Equipment so that it pumps a conti nuous flow of concrete without air pockets and without an appreciable loss of slump or entrain ed air. The Contractor shall control the loss of entrained air by one (1) or more of the following methods: 1. Tie the end of the pump hose so that the discharge end is po inting upward, forming a “J” at the end of the hose; 2. Install a series of four (4) consecutive elbows to form a 36 0° loop; Section 511: Concrete Structures Page 362 3. Reduce the diameter of the end of the pump line; or 4. Limit the enclosed angle of the boom arms to an angle of 135 ° or more. The Contractor shall make sure that the discharge of the concr ete from the pump is as close as possible to the bottom of the structure being placed, but in no case shall it be allowed to drop a distance greater than four (4) feet with the exceptio n of CBC walls where the walls equal to or less than ten (10) inc h thick, concrete may have a free fall of less than nine (9) ft. The Contractor shall not use aluminum pipe. The Contractor sh all not add water to the concrete during pumping. If water is added at the pump hopper to clear a clogged pump, the Contractor shall dispose of the concrete in the hopper and the line.

511.3.5 3 Conveyers and Belts The Contractor may use conveyor belts to transport the concret e from the point of

delivery to the point of placement. If using multiple belts, t he Contractor shall ensure that the drop from one (1) belt to the next is no greater than 18 inches . At the end of the last belt, the Contractor shall not allow the concrete to free-fall more than four (4) ft. The Contractor shall ensure that the concrete coming off the end of any belt is not being segregated. If segregation occurs, the Contractor shall slow down the speed of the belt un til segregation no longer occurs.

511.3.5 4 Placing Concrete Under Water

If placing concrete under water, the Contractor shall submit a mix design and procedure plan to the Project Manager. The Project Manager may require u p to 30 Days to approve them. The Contractor shall allow time in the schedule to accom modate this approval process.

511.3.5 5 Vibrating/Consolidation

Unless otherwise directed by the Project Manager, and excludin g drilled shafts, the Contractor shall consolidate concrete with suitable mechanical vibrators operating within the concrete. During concrete placement, the Contractor shall keep enough personnel, vibrators, and other tools available to assure adequate consolidation. If necessary, the Contractor shall supplement vibrating with hand s pading with suitable tools to a ssure proper consolidation. If using vibrators, the Contractor shall use procedures in accorda nce with ACI 309 – Consolidation of Concrete. The Contractor shall not use a “jitterbug” or any other flat t ool that could cause concrete segregation. The Contractor shall use vibrators that have each been certifi ed within the last 90 Days to provide 8,500 to 12,500 Vpm. The Contractor shall operate vibrators to consolidate the conc rete thoroughly around the reinforcement and embedded fixtures and into corners and angles of the forms. The Contractor shall not use vibrators to make concrete flow or run . The Contractor shall vibrate long enough to accomplish consolidation, but do not vibrate so long to cause segregation or air bubbles. The Contractor shall insert the vibrators vertica lly into the concrete, and immediately withdraw upward along the same line with the opposi te motion. The Contractor shall not drag the vibrator horiz ontally across the placing are a. When operating vibrators, the Contractor shall avoid contact w ith reinforcing bars, particularly epoxy coated reinforcing bars or bars that extend into concrete that has taken an Section 511: Concrete Structures Page 363 initial set. If vibrating concrete in areas reinforced with ep oxy-coated bars, the Contractor shall cover the vibrators with nonmetallic sleeves to prevent damage to the epoxy coating.

511.3.5 6 Sequence of Placement and Application of Load

The Contractor shall not place superimposed loads on or agains t load carrying members, floor slabs, or retaining walls until the concrete reaches 75% of specified design compressive strength but no less than 2,500 psi, determined in accordance w ith Section 510.3.5.2, “In- Place Concrete Strength Measurem ents.” Concrete Box Culverts a nd CBC wingwalls shall not be backfilled until specified design compressive strength h as been achieved. The Contractor shall submit a concrete placement schedule to t he Project Manager upon request. The Contractor shall plan and schedule concrete place ment to prevent damage to previously placed concrete or to the curing or protection syste ms of previously placed concrete. The following applies to concrete placement scheduling: 1. The Contractor may erect reinforcement and formwork for wall s, columns, and pier caps 24 h after placement of foot ings or floor slab concrete. Unless otherwise provided, the Contractor may pl ace concrete columns, walls, and pier caps, 48 h after placement of footing or floor slab concrete; 2. The Contractor shall not set beams or girders, or place Supe rstructure concrete until Substructure forms have been st ripped sufficiently to determine the quality of the concrete; 3. The Contractor shall not place the load of the Superstructur e on the Substructure until the Substructure concrete has been in place for at least 14 Days or until in- place strength measured by the Maturity Method indicates that t he concrete has attained 75% of the design strength; 4. The Contractor shall ensure that the concrete has achieved s ufficient strength as determined by the Maturity Method in accordance with the form d esign before placing concrete for integral h orizontal members, such as pier caps or top slabs; 5. The Contractor shall place the vertical members at least sev en (7) Days before mounting friction collars or falsework brackets that will suppo rt the weight of horizontal members. The Contractor shall ensure that the verti cal members have attained the specified strength before applying loads, unless t he Department approves otherwise; 6. The Contractor shall limit monolithic casting of walls and d eck slabs of concrete box Culverts to Culverts that are six (6) ft high or less. The Con tractor shall construct box Culvert walls higher than six (6) ft in accordance with thi s subsection; and 7. If the concrete is not gaini ng strength as expected, the Ass istant District Engineer of Construction may extend the waiting periods. The Contractor sh all conduct construction operations in a ma nner that does not damage the pr eviously placed concrete.

511.3.5 7 Supplementary Lighting

The Contractor shall not mix, place, or finish concrete when t he natural light is insufficient without using an adequate artificial lighting system, approved by the Project Manager. The Contractor shall test the lighting system at least one (1) Day before placing the concrete to assure that the system will provide sufficient light, without s hadows or dark areas for placing, testing and finishing concrete. The Contractor shall ensure th at the lights do not create a hazard for traffic on adjacent Roadways or Detours.

511.3.6 Removal of Forms

The Contractor shall not remove the forms until the concrete i s strong enough to avoid damage by removing the forms. If in-place strength tests in accordance with Section 510.3.5. 2 , “ I n - P l a c e C o n c r e t e Strength Measurements,” are not used to control field operation s, the Contractor shall remove forms in accordance with Table 511.3.6:1, “Timetable for Remova l of Forms,” not counting those Days when the temperature is below 40 °F. Table 511.3.6:1 Timetable for Removal of Forms Structural component Minimum time for removal Bottom of beams 14 Days Bridge decksa seven (7) Days Floor slabs seven (7) Days CBC Floors seven (7) Days CBC Top Slab seven (7) Days Walls 24 h Columns 48 h Sides of beams 24 h All other parts 24 h aAdditional requirements of Secti on 512, “Superstructure Concret e,” shall apply. If one (1) of the test methods in Section 510.3.5.2, “In-Place Concrete Strength Measurements,” is used to control the field operations, the Con tractor may remove forms from the bottom of beams and floor sl abs when the concrete reaches 7 5% of the design compressive strength.

511.3.7 Joints

The Contractor shall make construction joints in concrete Stru ctures in accordance with the Plans, unless otherwise direc ted or approved by the Project Manager. If the concrete placement is interrupted and additional constr uction joints are required, the Contractor shall place the additional joints in planes perp endicular to the principal lines of stress, and at points of minimum shear, as approved by the Proj ect Manager.

511.3.7 1 Keyed Joints

The Contractor shall mechanically bond construction joints wit h keys formed by beveled strips embedded in the surface of the concrete. The Contractor shall make the keys from 1 3/8 inch to 1 1/2 inch deep. The Contractor shall place the ke ys centrally within the thickness of the joint. The Contractor shall ensure that the keys have a width that is one-third (1/3) of the depth of the smallest dimension of the joint. The keys do not need to exceed the clear distance between reinforcing mats, or be greater than eight (8) inches. The Contractor shall provide raised keys in accordance with the Plans.

511.3.7 2 Bonding New Concrete to Existing

If bonding new and existing concrete, the Contractor shall ret ighten the forms before Section 511: Concrete Structures Page 365 depositing new concrete on or against the hardened concrete. T he Contractor shall roughen the surface of the hardened concrete without loosening the aggr egate or damaging the concrete on the surface. The Contractor shall thoroughly clean the surface of foreign matter and laitance. The Contractor shall utilize a bonding method at the interface between the hardened and fresh concrete. It is Accept able to utilize an enriched mortar or a bonding agent. When using enriched mortar, the Contractor shall saturate the surface of t he concrete and scrub the enriched motar onto the entire surface with a nylon bristled br ush. The Contractor shall place the new concrete before the enriched mortar reaches an initial set. If using a bonding agent, the Contractor shall follow the manufacturer’s application inst ructions. The Contractor shall place the concrete continuously f rom joint to joint, and finish the face edges of exposed joints in accordance with the Plans. 511.3.7.3 Water Stops and Flashings The Contractor shall provide and place water stops, and flashi ngs per the Contract documents. The Contractor shall splice or solder water stops a nd flashings to form continuous watertight joints. Swellable hydrophilic waterstop shall be installed with two (2 ) inch minimum concrete cover. Materials shall be instal led per manufacturer’s install ation instructions.

511.3.7 4 Joint Sealing Materials

The Contractor shall install jo int sealers in accordance with the manufacturer’s recommendations, including surface preparation and the use of p rimers and backer-rod as required.

511.3.8 Miscellaneous Construction

511.3.8 1 Setting of Bearings

The Contractor shall ensure the surfaces on which metal masonr y plates and elastomeric bearing pads will rest are flat and on level planes. If using elastomeric bearing pads, the Contractor shall finish the Bri dge seats slightly high and grin d to the correct elevation. If it is necessary to adjust the elevation of a bearing upward , the Contractor shall make the adjustment by placing full si ze shim plates. If it is nece ssary to adjust the elevation of a bearing downward, the Contractor shall make the adjustment by d iamond grinding to a level plane-bearing surface. The Contractor shall not use grout to l evel or adjust elevation. If placing a bearing surface bel ow the level of adjacent concr ete, the Contractor shall ensure water drains away from the masonry plate or elastomeric bearing pad. The Contractor shall finish sections of Bridge seats on abutme nts or piers on both sides of bearing assemblies to drain, with a slope of from 1/16 inch to 1/8 inch per foot. The Contractor shall correct depressions that retain water.

511.3.8 2 Waterproofing

If required in the Contract, the Contractor shall protect the backsides of abutment backwalls and wingwalls by waterproofing. The Contract shall d efine the vertical and horizontal limits of the waterproofing. The Material shall be installed in conformance with the manufacturer’s application instructions.

511.3.9 Finishing

The Contractor shall perform finishing after removing forms in accordance with the Contract.

511.3.9 1 Exposed Surfaces

The Department considers “exposed surfaces” as surfaces that a re not buried in the ground or permanently covered by the fill, or against which the fill is not permanently placed. However, the Department does not c onsider the inside surfaces o f concrete box drainage Culverts and concrete box girders, and the bottom side of concr ete Bridge decks as “exposed surfaces.” 511.3.9.2 Class 1, Ordinary Surface Finish The Contractor shall apply a Class 1 finish to exposed surface s as a final finish or before a Class 2, Rubbed Surface Finish, or a Class 4, Special Surface Finish. A Class 1 finish includes the removal of rods, bolts, or other form ties to at least 1/2 inch deep from the face of the concrete. The Contractor shall fill tie holes and honeycombs with mortar composed of one (1) part cement and two (2) parts sand; the Contractor shall use the same brand and type of cement as used in the concrete. The Contractor shall remove objectionable fins, bulges, and pr ojections by rubbing with carborundum bricks or by other methods approved by the Project Manager. If necessary, the Contractor shall clean the entire surface. The Contractor shal l keep such surfaces in an Acceptable condition until Fi nal Acceptance of the Work. The Contractor shall apply a Class 1 finish to surfaces buried in the ground or permanently against the fill, except that form ties may be cut off even with the concrete surface, and fins, minor bulges , projections, stains, and disco lorations do not need to be removed. Unless specified otherwise in the Contract, the Contractor sha ll apply a Class 1 finish to the front faces of backwalls of abutments, the top surfaces of Bridge seats on piers and abutments, and concrete curtain walls between pier pilings. The Contractor shall apply a Class 1 finish to the inside surf aces of concrete box drainage Culverts, except as noted in Section 511.3.8.3, “Class 2, Rubbed Surface Finish.”

511.3.9 3 Class 2, Rubbed Surface Finish

The Contractor shall apply a Class 2 finish to concrete surfac es generally exposed to public view. The Contract may specify a Class 4, Special Surface Finish wit h selected colors, for various components or parts of components. If the Contract spe c i f i e s a C l a s s 4 , S p e c i a l Surface Finish, the Contractor shall apply a Class 2 finish fir st, unless otherwise approved by the Project Manager. A Class 2 finish consists of a Class 1 finish, then thoroughly wetting the surface and applying a mortar. The Contractor shall apply a thin mortar, in accordance with S ection 511.2.1.1, “Concrete Section 511: Concrete Structures Page 367 Surface Finishing Materials,” and rub it into holes and pockets in the surface of the concrete. The Contractor shall allow the mortar to remain until it has se t sufficiently to prevent removal by subsequent rubbing operations. The Contractor shall rub the surface with a No. 25 to No. 30 carborundum brick, then, rub with burlap to remove exces s mortar. If the completed rubbed surface does not look uniform, the Contractor shall make a final finish by wet rubbing with a No. 30 carborundum brick. The Contractor shall apply Class 2 finish to the following: 1. Outside vertical surfaces of Bridge decks; 2. Outside surfaces of exterior girders, curb and rail posts se en in elevation view; 3. Curb tops, post tops, inside fa ces of curbs, and faces of ha nd rails; 4. Exposed surfaces of pier columns and caps; 5. Abutment wingwalls and Bridge seats one (1) ft below final g rade; 6. Bridge rehabilitation Projects with existing slope paving; 7. Top surface of slope paving (tops of Bridge seats require on ly a Class 1 finish); 8. Exposed surfaces of barrier r ailings on Bridges or concrete box Culverts; 9. Exposed surfaces of miscellaneous concrete Structures extend ing above Shoulder line grade and inside walls of concrete underpass Structures; 10. Concrete box Culverts used for drainage, on the soffit and streamside faces of headwalls and wingwalls, and for six (6) inches down the back s ide of wingwalls; and 11. The interiors of sidewalls to one (1) ft back from the face of the Culvert at the tops of the sidewalls, and extending on a 45° line downward and inward.

511.3.9 4 Class 3, Float Finish

The Contractor shall apply a Class 3 finish to upper surfaces not formed, such as tops of walls, headwall, tops of slabs and bottom slabs of box Culverts , copings and Bridge seats, except tops of Bridge decks, Sidewalks, or curbs. A Class 3 finish consists of placing an excess amount of concr ete in the forms and striking off this excess concrete with a template, forcing the coarse aggregate below the surface. After striking off the concrete, the Contractor shall thoroughly work the surface with a wooden, cork, or canvas float without adding water or cement. Before the final finish has set, the Contractor shall use a fine brush to remove surface film an d to produce a fine grain, smooth, sanded texture.

511.3.9 5 Class 4, Special Surface Finish When specified in the Contract documents, the Contractor shall apply a Class 4, Special

Surface Finish. The Class 4, Special Surface Finish shall be a pplied in accordance with Specification Section 548, “Coating of Concrete.” The Contractor shall apply the Class 4 finish over the Class 2 finish, unless directed otherwise by the Project Manager. The Contractor shall apply the Class 4 finish consistent with the location requirements of Section 511.3.8.3, “Class 2, Rubbed Surface Finish.” If repair ing existing Structures, apply a Class 4 finish to the entire surface of the repaired components .

511.3.10 Curing

The Contractor shall cure all concrete in accordance with ACI 308 – Guide to Curing Concrete. All concrete shall receive a minimum of seven (7) Da ys of curing treatment. The Contractor shall use curing methods in accordance with Table 51 1.3.10:1, “Curing of Concrete Structures,” unless the Contract specifies otherwise. If the Department allows the Contractor to choose the curing m ethod, the Contractor shall obtain the approval of the Project Manager before beginning cur ing operations. Table 511.3.10:1 Curing of Concrete Structures Method designation Curing method description Method 1 Water curing Method 2 Curing compound Method 3 Form curing Method 4 Combination of Method 1 and Method 2 Structure description Curing methods Top surfaces of: Bridge decksa 4 Approach slabs 4 Concrete curbs, gutters and Si dewalks 1 or 2 Pier caps, abutment Bridge seats 1 or 2 Wingwalls and parapet walls 1 or 2 All vertical concrete surfaces that begin in contact with form Materials, including but not limited to: Barrier walls, barrier railing, wingwalls, parapet walls, abutments, box culverts, de cks, slabs, curbs, gutters, sidewalks, construction joints Elevated horizontal surfaces on the underside of structural elements that begin in contact with temporary form Materials including but not limited to: pier caps, girders, structural slabs Slip Formed Concrete elements including but not limited to: Concrete wall barriers, curb, gutter All other concrete b 3 1, 2, or 3 aSee Section 512.3.10.1, “Curing ,” for additional curing require ments for Bridge decks. bUnless the Contract specifies otherwise.

511.3.10 1 Method 1, Water Curing

The Contractor shall keep the concrete thoroughly and continuo usly wet and covered for at least seven (7) Days. The C ontractor shall place and anchor covers, mats, and sheeting to ensure continuous contact wit h the concrete surfaces. The Contractor shall cover concrete slabs as soon as possible with a double layer of clean, wet burlap or cotton mats, or other moisture retaining M aterial approved by the Project Section 511: Concrete Structures Page 369 Manager. The Contractor shall ensure that the moisture retaini ng Materials lay flat with no wrinkles and that adjacent strips of moisture retaining Materia ls overlap at least 12 inches. After installation, the Contractor shall soak the moisture reta ining Material and add moisture as required to ensure that it is not allowed to become dry for the duration of the specified curing period. The Project Manager will determine the suitability of the moisture retaining Material for reuse, based on the cleanliness and absorptive ability of the M aterials. In addition to the moisture absorptive Material, the Contracto r shall install plastic sheeting over the moisture absorptive Mate rial. If the slabs are on gra de, the Contractor shall extend the cover Materials at least twice the slab’s thickness beyond the edges of the slab, and make sure that the entire exposed surface of the concrete is protect ed. If the slab is a Bridge deck, the Contractor shall place the cover Materials to fully protect exposed edges and unformed surfaces of the concrete. The Contractor may temporarily remove the cover from surfaces that require a rubbed finish for finishing, but shall restore the cover as soon as po ssible.

511.3.10 2 Method 2, Curing Compound

Application of curing compound shall be in accordance with man ufacturer’s application recommendations. For slabs, Bridge decks and other flatwork, the Contractor sha ll apply the curing compound to the fresh concrete as soon after finishing as allow ed by the manufacturer. The Contractor shall thoroughly mix the membrane forming curin g compound per the manufacturer’s recommendations. The Contractor shall not apply the curing compound in rainy co nditions. The Contractor shall adhere to the thermal limitations as specified by the man ufacturer – typically, the product when stored should not be allowed to freeze and should not be a pplied when the air or concrete temperature is less than 40 degrees Fahrenheit. The Contractor shall apply the curing compound under pressure with an atomizing-type spray nozzle. The Contractor shall uniformly cover the entire surface area at the rate recommended by the manufacturer or at a rate of at least one (1 ) gal per 175 ft 2 whichever rate is greater. The Contractor shall use spray Equipment with enough pressure to force the curing compound to leave the nozzle as a fine mist. If the noz zle becomes plugged, the Contractor shall immediately clear the nozzle before continuing the application. The Contractor shall not continue to spray curing compound through a nozzle that has become plugged or obstructed. The Contractor shall apply the curing compound by first sprayi ng back and forth in one

511.3.10 3 Method 3, Form Curing

The Contractor shall leave forms in place in accordance with Se ction 511.3.6, “Removal of Forms.” The Contractor shall keep wood forms moist during t he curing period and replenish the system with water to maintain a continuously moist conditio n. The Contractor shall cure exposed surfaces with Methods 1 or 2. Form removal shall be in accordance with Section 511.3.6, “Rem oval of Forms.” Should forms be removed prior to the specified seven (7) day curing pe riod, the Contractor shall immediately resume curing by Method 2. For Structures with formed surfaces that require the applicati on of a finish per Section

511.3 8, “Finishing” such as bar rier walls, barrier railings on Bridges, wingwalls, or parapets on

Bridges or box Culverts, the Contractor shall remove the forms in accordance with Section

511.3 6, “Form Removal,” finish the concrete in accordance with Section 511.3.8, “Finishing,”

and resume curing with Method 2 for the duration of the curing period. The Contractor shall not pause curing for more than two (2) hours.

511.3.10 4 Method 4, Combination of Curing Compound and Water C uring

The Contractor shall apply Method 2 curing compound as soon af ter finishing as is allowed by the manufacturer. When the concrete is hard enough that placement loads and burl ap or cotton mats can be applied without marring the concrete surface or deformation of structural elements, the Contractor shall apply Method 1 curing directly over the curing compound coated surface.

511.3.10 5 Equipment and Personnel Readiness

The Contractor shall show the Project Manager that curing Mate rial and Equipment (including backup sprayers and mi xers) are in working order, at least one (1) Day before concrete placement.

511.3.10 6 Temperature Requirements for Storage and Application

The Contractor shall store curing compounds in protected areas away from weather and extreme temperatures and per the manufacturer’s recommendations . The Contractor shall dispose of compounds that have been frozen in storage. The Con tractor shall apply curing compounds when the temperature of the compound is between 50 °F and 95 °F.

511.3.10 7 Penetrating Water Repellent Treatment Solution

The Contractor shall saturate the exposed surfaces of the foll owing concrete Structures with a penetrating water repellent treatment in accordance with Section 532, “Penetrating Water Repellent Treatment” for: 1. Bridge wingwalls; 2. Front and side faces of abutment Bridge seats; 3. Front faces of abutments, backwalls and diaphragms; Section 511: Concrete Structures Page 371 4. Top surfaces of Bridge seats on piers and abutments; 5. Pier columns, stem walls and ve rtical surfaces of pier caps; 6. Top and vertical side surfaces of Bridge decks, except in th e areas where using epoxy Bridge deck overlays; 7. Top surfaces of concrete approach slabs; 8. Concrete barrier railings; 9. Concrete wall barriers; and 10. Sidewalks, curbs and gutters on Structures. The Contractor shall extend treatment to at least one (1) ft b elow the final groundline. The Contractor shall not treat the underside of pier caps, or side and end surfaces of concrete approach slabs. 511.4 METHOD OF MEASUREMENT The Department will measure all pay items using the dimensions shown in the Contract or approved modifications.

511.5 Basis of Payment

Pay Item Pay Unit Structural Concrete, Class ____ Cubic Yard Structural Concrete, Class ____, ____ inch Square Yard Substructure Concrete, Class ____ Cubic Yard

511.5.1 Work Included in Payment

The following Work and items will be considered as included in the payment for the main item(s) and will not be measured or paid for separately: 1. Waterstops and flashings; 2. Waterproofing; 3. Premolded and preformed joint fillers; 4. Concrete required to fill overbreakage in excavation when fo otings or walls are cast against vertical or horizont al faces of excavation; 5. Installation of drains and weep holes; 6. Extruded polystyrene; and 7. Means and methods associated with placement of concrete in h ot and cold weather conditions, including but not limited to wind break, fogging sy stems, and temporary heat. Section 512: Superstructu re Concrete Page 372