READY MIX
QUALITY CONTROL STATEMENT
Thelen Sand and Gravel is committed to producing only the highest quality materials. A strict quality control program monitored by trained technicians ensures that Thelen is ahead of the quality control curve. Our labs are equipped with state-of-the-art technology to properly test all our materials. The following are Thelen’s testing guidelines and/or procedures:
Fine Aggregate Moisture Content by the Flask Method – ASTM C 70, (Illinois Modified) Tested weekly and on days of large pours.
Total Moisture Content of Aggregate by Drying – ASTM C 566, AASHTO Designation T 255-00 (Illinois Modified) The method used to check coarse aggregate moisture content. Done weekly and on days of large pours.
Sampling Freshly Mixed Concrete – ASTM C 172, AASHTO Designation T 141-05 (Illinois Modified)
Temperature of Freshly Mixed Portland Cement Concrete – ASTM C 1064
Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete – ASTM C 138, AASHTO Designation T 121M/T 121-05 (Illinois Modified) The Unit Weight and Yield are checked when concrete is tested at the lab or when there is a question of yield. We typically do not do a gravimetric calculation on the air.
Air Content of Freshly Mixed Concrete by the Pressure Method – ASTM C 231, AASHTO T 152-05 (Illinois Modified) This is the typical method we use to test the air content of concrete (other than lightweight concrete).
Air Content of Freshly Mixed Concrete by the Volumetric Method – ASTM C 173, AASHTO T 196M/ T196-05 (Illinois Modified) This is the test method used for checking air content of lightweight concrete (It can be used for all types of concrete, however, the pressure method is much quicker).
Making and Curing Concrete Test Specimens in the Field – ASTM C 31, AASHTO Designation T 23-04 (Illinois Modified) Concrete Test Cylinders are taken in the field for large pours or when requested by the engineer / contractor. We bring the test cylinders back to the lab for curing by the following day.
Making and Curing Concrete Test Specimens in the Laboratory – ASTM C 192, AASHTO Designation R 39-05 (Illinois Modified) Concrete Test Cylinders are made in the Lab for most all tests done, large pours, QCQA backup cylinders, when requested by the contractor, or when doing trial mix designs.
Note: Aggregate Tests ASTM D 75, ASTM C 136 and ASTM C 117 also pertain to ready mix.
Concrete Mix Designs & History: We have an extensive list of mix designs for all types of projects. Strength and historical test data is maintained on a database. We have personnel certified to design mixes for IDOT projects.
Concrete Troubleshooting and Testing of In-Place Concrete: - We have personnel with years of concrete troubleshooting experience who can diagnose problems in the field. We can perform rebound hammer tests to indicate strength of in-place concrete.
Lab, Plant, & Truck Certifications: - Our Ready Mix Concrete plants at Antioch, Waukegan, and River Road are certified by IDOT for QCQA concrete production. The material batch scales are calibrated and certified yearly by an outside source along with IDOT. The chemical admixture dispensers are calibrated and certified by IDOT along with representative of the Chemical Admixture suppliers. Only chemical admixtures on the approved material lists are used for IDOT projects. The Ready Mix Plants at Antioch, Waukegan, River Road and Wilmot are certified by the National Ready Mixed Concrete Association bi-annually. All concrete ready mix trucks are certified and maintained by our Truck Mechanics Shop. The labs at Antioch, Waukegan and River Road are certified by IDOT for the testing of QCQA concrete yearly. All lab equipment is certified by IDOT on a yearly basis. Scales and Balances are calibrated yearly by an outside source. Lab Equipment is checked weekly / monthly and maintained.
Personnel Certification:
Onsite technicians have the following certifications:
• American Concrete Institute as an ACI Concrete Field Testing Technician – Grade I.
• Certified by IDOT for PCC Level I, II and III concrete. Only those certified as PCC Level III can design concrete mixes for use in IDOT projects.
• Attended the 5 day Quality Concrete Seminar put on by the St. Marys Cement Company.
• Attended the 4 day program - Concrete: Principles and Practice and the 2 day program - Aggregate and Chemical Admixtures for use in Concrete at the Portland Cement Association.
• Completed the IDOT ½ day concrete tester training.
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