q  Aggregates; dividers, bins, no co-mingling, certified materials only, storage and stockpiling


q  Cement storage; no co-mingling, certified Mill Test Reports with each shipment


q  Curing times and methods (general)


q  Adverse weather protection, control methods


q  Repairs; done prior to shipping with prior approval of the engineer and/or his representative


q  Stencils; class, design, date of manufacture, plant ID and trademark inside. Products must be marked no later than 24 hours after being made, once inside and once outside on opposite walls to indicate top.


q  Materials; must comply with applicable requirements of Division 41 the Iowa DOT Standard Specifications and IM requirements.


q  When requested by the Contractor, pipe may be furnished with not more than two lift holes. Lift holes shall not be larger than 2 inches in diameter and shall be cast or formed in a manner so that there are no breaks of the circumferential reinforcing of single-cage reinforced pipe or of the inner cage of double-cage reinforced pipe. When practicable, circumferential wires will be bent slightly to provide for the lift holes.


Cutting of circumferential wire in lift hole locations will be permitted if the pipe with the cut circumferential wire satisfies the 0.01-inch crack test requirements of AASHTO M170 for the specified class of pipe.


q  Forms on clean, smooth, level base when concrete is placed


q  External vibrators; insure not to dent or cause damage to forms.


q  Reinforcements; cages machine formed, certified materials, proper concrete coverage and positioning. Reinforcements shall meet the requirements of IM 107.


q  General workmanship


q  Record keeping; daily production logs, quality control tests, certified material tickets, ready mix tickets (if applicable) and any other pertinent information


q  Plant quality control operations and approved Quality Control Plan


q  Batching equipment for concrete calibrated yearly


q  Cure storage (if outside operations)


q  Formed concrete units shall have minimal honeycomb


q  Yarding; 2-ft. apart minimum, both ends readily accessible for inspection


q  Permissible variations; see referenced AASHTO, ASTM, and Iowa DOT Standard Specifications and IMs





q  Failure to comply with the approved quality control procedures


q  Failure to conform to any specification requirements


q  Defects indicating mixing and molding which does not conform to specifications


q  Fractures or cracks passing through the wall of the unit, except single end cracks that do not exceed depth of joint


q  Excessive honeycombed surface or open texture that would adversely affect the function of the unit


q  Damaged or cracked ends


q  Failure to conform to dimensional requirements (diameter, wall thickness, length and length of two opposite sides, design, concrete coverage reinforcement, positioning, etc.)


q  Not meeting strength requirements (cylinders, 3-Edge Bearing Test)


q  Any continuous crack 0.01 or more, 12 inches or more anywhere in the wall of the pipe or unit


q  Failure to stamp, mark and/or identify the finished item