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. Following are Thelen’s testing guidelines and/or procedures:
Sampling of Aggregates - ASTM D 75, AASHTO Designation T 2-91 (Illinois Modified) Both production and stockpiled IDOT materials are sampled weekly.
Sieve Analysis of Fine and Coarse Aggregate – ASTM C 136, AASHTO Designation T 27-99 (Illinois Modified) Gradations are done weekly on all production and stockpiled IDOT materials.
Materials Finer Than No. 200 Sieve in Mineral Aggregates by Washing – ASTM C 117, AASHTO Designation T 11-97 (Illinois Modified) All samples for IDOT are washed to determine the percent finer than the No. 200 sieve.
Flat and Elongated Particles in Coarse Aggregate – ASTM D 4791, (Illinois Modified) Although not a requirement in the state of Illinois, Thelen maintains the capability to run this test upon request.
Determining the Percentage of Fractured Particles in Coarse and Fine Aggregate – ASTM D 5821, (Illinois Modified) Done on all of our crushed products including manufactured sand.
Lab and Material Certifications: Our Aggregate sources at Antioch (North & South pits), Petersen and Lange Rd. All have certified aggregates in the IDOT Aggregate Gradation Control Program. The lab at Antioch is certified by IDOT to handle Antioch, Petersen and Lange Rd. QCQA aggregate production. 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 and maintained. For the products in the IDOT AGCS program, Master Bands are established and Gradation Control Charts are maintained daily.
Personnel Certifications: Onsite technicians are ASTM certified QC technicians and have successfully completed the IDOT Five Day Aggregate Technician Course and/or completed the ½ Day Aggregate Tester Class.