SUGGESTED GUIDELINES

MINIMUM REQUIREMENTS FOR PLANT APPROVAL

CONCRETE PIPE & RELATED PRECAST UNITS

 

AGGREGATES

 

         Source Approval

         Gradation

         Quality Requirements

 

MIX DESIGN (Pre-approved Mix)

 

         Target Combined Gradation Mix Design

         Batch Weights

         Minimum Cement Content

         Strength

         Slump

 

QUALITY CONTROL PLAN

 

         QC Duties & Responsibilities

         Frequency of Measurements

         Frequency of Testing

         Calculation

         Rebar & Wire Placement

         Welding and/or Tying

         Reports and Reporting

         Certified/Qualified Personnel

 

PLANT CALIBRATION

 

         Frequency (Minimum once per year)

         Accuracy of Scale

         Calibration by an Approved Agency & Witnessed by Iowa DOT staff

 

TESTING

 

         Frequency - Strength in Accordance with the Requirements of IM 445

         Frequency Pipe Testing in Accordance with the Requirements of IM 445

         Frequency Absorption Testing

         Frequency Gradation Testing

 

MARKING & IDENTIFICATION

 

         Markings/Stamping Class, design, plant ID, date of manufacture, and trademark should be plainly marked or stenciled on the inside of the pipe near the tongues no later than 24 hours after the pipe or the precast unit is made.

 

PRODUCTION PROCESS

 

         Welding (Certified Welders)

         Mixing

         Curing

         Handling

         Storage

 

CERTIFICATION REQUIREMENTS

 

         Certified Aggregate Technician

         A certified aggregate technician must perform the aggregate gradation. Certified gradation from the aggregate source is acceptable.

         Certified PC Plant Technician Level I

 

DOCUMENTATION

 

         Certification statement

         Documentation of measurements, mixes, etc.

         Reports and reporting

 

OTHER MATERIALS

 

         Cement - Approved Sources Mill Test Reports

         Reinforcing Steel - Approved Sources Mill Test Reports

         Wire - Approved Sources Mill Test Reports

         Admixtures - Approved Sources Certifications