269 SECTION 504 DESCRIPTION
504.01.01 General. This work consists of furnishing and placing lightweight Portland cement concrete in
bridges, culverts, and other types of concrete structures. MATERIALS
504.02.01 General. Material shall conform to the following Sections and Subsection:
Portland Cement Concrete ................................ ................................ ................................ ................................ ..................... Section 501 Admixtures ................................ ................................ ................................ ................................ .............................. Subsection 501.02.04 Concrete Structures ................................ ................................ ................................ ................................ ............................... Section 502 Aggregates for Portland Cement Products ................................ ................................ ................................ ............................. Section 706
504.02.02 Concrete Making Properties. Lightweight concrete shall be subject to the following requirements
and test methods: Test Test Method Requirements Making Test Specimens (laboratory) ................................ ............... ASTM C192 ................................ .......... — Making Test Specimens (field) ................................ ........................... Nev. T428 ................................ .......... — Compressive Strength ................................ ................................ ..... ASTM C39 * ................................ ....... Table I Unit Weight & Cement Factor (wet) ................................ .................... Nev. T435 ................................ ....... Table I Tests for Popouts ................................ ................................ ............ ASTM C330 ............................ No Surface Popouts Air Content ................................ ................................ ......................... Nev. T431 ................................ ....... Table I Slump ................................ ................................ ................................ . Nev. T438 ................................ ....... Table I Air Dried Weight ................................ ................................ .............. ASTM C567 ................................ ....... Table I Coring Concrete ................................ ................................ ................ ASTM C42 ........................... Subsection 504.04.01 * The compressive strength requirements of Portland cement concrete will be based on the strength test, which is defined as the average of the breaking strength of 3 standard cylinders at 28 days. The compress ive strength test will be required for each 38 m3 (50 yd3), or portion thereof, placed each day. For large continuous pours, one test near the beginning of the pour and one test near the end of the pour may be substituted for the 38 m3 (50 yd3) requirement. Other cylinders may be made and broken for informational purposes. CONSTRUCTION
504.03.01 General. The construction of conventionally reinforced lightweight concrete structures shall conform
to Sections 501 and 502, with the exceptions contained in this Section. Give not less than 32 days notification in advance of use of the proposed sources of materials and make arrangements for the Engineer to obtain samples as required for testing purposes. Samples will not exceed 225 kg (500 lb) fo r each separate grading. Furnish a written statement giving the amount of cement in kg/m3 (lb/yd3), the proportions of cement and each size of aggregate in a saturated surface dry condition, the slump, and the percentage of air in the concrete proposed for use in the work. If proposing to use an admixture other than an air -entraining agent, state its complete brand name and the quantity proposed to be used per m3 (yd3) of concrete. The Engineer, after making such tests as deemed advisable, will either acc ept the proposed materials and proportions or suggest modifications needed for acceptance. After acceptance of batch proportions and materials, do not alter them during the course of the work except as found necessary to maintain yield, amount of cement, and unit mass within specification requirements. Do not revise batch proportions resulting in concrete that contains an amount of total water per cubic meter (cubic yard) greater than 105% of that contained in concrete of the accepted proportions.
504.03 02 Storage of Aggregates. Stockpile lightweight aggregate on the job or at a central batching plant for
a minimum time of 24 hours before its use. Stockpile fine and coarse aggregates separately. 504 LIGHTWEIGHT CONCRETE FOR STRUCTURES 270 504.03.03 Classification and Proportions. Proportion lig htweight concrete by mass, such that the requirements in Table I will be satisfied. Give advance notice in writing when any changes are to be made in the batch proportions. Do not vary batches of lightweight concrete more than ± 50 kg/m3 (± 3 lb/ft3) in u nit mass from the design mix. The amount of cement of any individual batch placed in the work shall not be more than 8 kg/m3 (14 lb/yd3) less nor more than 14 kg/m3 (23 lb/yd3) greater than the amount designated on the design mix. Batch aggregates and repo rt to the Engineer by mass. The masses used may be varied as necessary to comply with the above tolerances in amount of cement and unit mass. TABLE I Class of Concrete Cement Range kg/m3 (lb/yd3) Maximum Water Cement Ratio kg/kg (lb/lb) Minimum Compressive Strength MPa (psi) Slump Range mm (in.) Entrained Air Range % Maximum Air Dried Mass kg/m3 (lb/ft3) LA 330-420 (564 -705) 0.53 (0.53) 21 (3,000) 25-100 (1 -4) — 1,842 (115) LAA 330-450 (564 -752) 0.49 (0.49) 21 (3,000) 25-100 (1 -4) 4-7 1,842 (115) LA or LAA, Mod ified 360-450 (611 -752) 0.53 (0.53) Specified on Plans 25-100 (1 -4) 4-7 1,842 (115) The maximum water/cement ratio is based on aggregate in a saturated surface dry condition. Natural fine aggregate may be used provided it does not result in concrete having a mass in excess of maximum.
504.03.04 Mixing. Produce workable concrete of uniform consistency. Use stockpiled aggregates in a
saturated surface dry condition just before batching. Charge the batch so that 75% of the total mixing water and admixtures are introduced in the mixer in advance of the aggregates. Introduce the aggregates and mix for a minimum of 45 seconds. The amount of absorption by the aggregate will be the determining factor in mixing time. Add the cement and final water and complete mixing. For stationary mixers, mix not less than 3 minutes. For truck mixers, mix not less than 100 revolutions of the drum. Operate the drum on truck mixers at high speed while charging it with aggregate. Introduce cement into th e mixing drum while it is rotating at slow speed. Immediately before discharge of the concrete, rotate the drum at high speed for at least 60 seconds. METHOD OF MEASUREMENT
504.04.01 Measurement . Lightweight concrete will be measured according to Subsect ion 502.04.01.
Reinforcing steel will be measured under Section 505. BASIS OF PAYMENT
504.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract
price per unit of measurement for the pay items listed below t hat are shown in the proposal. Payment will be full compensation for the work prescribed in this Section. Payment will be made under: Pay Item Pay Unit (class) Lightweight Concrete (Minor) ................................ ................................ ................................ ................. Cubic Meter (Cubic Yard) (class) Lightweight Concrete (Major) ................................ ................................ ................................ ................. Cubic Meter (Cubic Yard) 271 SECTION 505 REINFORCING STEEL DESCRIPTION
505.01.01 General. This work consists of furnishing and placing reinforcing steel and welded wire
reinforcement. MATERIALS
505.02.01 General. Material shall conform to the following Subsections:
Bar Steel Reinforcement ......................................................................................................................................... Subsection 713.03.01 Welded Wire Reinforcement .................................................................................................................................... Subsection 713.03.02 Use Grade 420 (60) bar steel reinforcement unless otherwise specified on the plans. Spiral reinforcement may be either bar steel reinforcement or steel wire, of the equivalent size of the bar steel. Use epoxy coatings listed in the QPL. Tie wire shall be commercial quality 1.5 mm diameter (16 gage) minimum, black annealed soft-iron wire, unless otherwise approved. Tie wires used on epoxy coated reinforcing steel shall be coated with plastic or an equal type coating as approved.
505.02.02 Samples. Furnish one extra bar of each diameter for each 90 metric tons (100 tons) or fraction
thereof. Select this bar from the longest bar of each size so that the bar, or a portion of it, can be used to replace any bar of that diameter which is selected to be used as a field sample. Supply field sample of sufficient length to provide for two 750 mm (30 in.) samples of each diameter. Indicate the extra bars on the fabricator’s details.
505.02.03 Specifications for Coating Reinforcing Steel. Coating of bar steel reinforcement shall conform to
AASHTO M284 (ASTM A775). Fabrication and handling of coated reinforcing steel shall conform to AASHTO M317 (ASTM D3963) except as provided herein. Patching or repair material shall conform to AASHTO M284 (ASTM A775) and shall be obtained from the coating manufacturer utilized to initially coat the reinforcemen t. Coating of welded wire reinforcement shall conform to ASTM A884, Class A. When approved in writing, zinc coating conforming to ASTM A993 may be substituted for epoxy coating. The coating fabricator for epoxy coated reinforcing steel shall be certified by the Concrete Reinforcing Steel Institute’s Certification Program for Fusion Bonded Epoxy Coating Applicator Plants. Submit a copy of the Epoxy Coating Certification along with notification of the starting date of coating application. Give notification of the date and location of the coating operation, in writing, at least 10 days before the planned date for beginning the coating operation. Allow the Engineer free access to the plant of the coating applicator for inspection. If the representative so elects, perform preparation of the bars, coating and curing of the bars in the representative’s presence.
505.02.04 Welded Hoop Reinforcing. Fabricate welded hoop reinforcing consisting of bar steel reinforcing
formed into a circular shape with ends connected by complete joint penetration butt welding or resistance butt welding according to Subsection 505.03.05 and the requirements herein.
a.General. Designate in writing a welded hoop reinforcing Quality Control Manager (QCM). The QCM shall be responsible directly to the Contractor for the quality of all welded hoop reinforcing including the inspection of materials and workmanship performed by the Contractor and all subcontractors and submitting, receiving, and approving all correspondence, required submittals, and reports regarding welded hoop reinforcing to and from the Engineer. The QCM shall not be employed or compensated by any subcontractor, or by other persons or entities hired by subcontractors, who will provide other services or materials for the project. The QCM may be an employee of the Contractor. The QCM shall be qualified as an AWS Certified Welding Inspector or approved equivalent and shall have a minimum of 3 years experience in the inspection/oversight of reinforcing steel welding. Provide verification of QCM qualifications at least 10 days before the planned date for beginning the welding operation.
Source: Nevada Standard Specifications for Road and Bridge Construction, 2014 Edition. Pages 275–276 of 610.