Quality Control Statement

Thelen Materials 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:

Sampling of Aggregate

ASTM D 75, AASHTO Designation T 2-91 (Illinois Modified). Both production and stockpiled IDOT and WisDOT 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 Aggregate by Washing

ASTM C 117, AASHTO Designation T 11-97 (Illinois Modified). All samples for IDOT and WisDOT 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.

State-of-the-Art Quality Control Program

Lab and Material Certifications:

Our Aggregate sources at Antioch (North & South), Petersen, and Lange Rd. all have certified Aggregate in the IDOT and WisDOT Aggregate Gradation Control Program. The lab at Antioch is certified by IDOT and WisDOT to handle Antioch, Petersen and Lange Rd. QCQA aggregate production. All lab equipment is certified by IDOT and WisDOT on a yearly basis. Truck scales, aggregate 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 WisDOT Aggregate Certification class and the IDOT Five Day Aggregate Technician Course and/or completed the Day Aggregate Tester Class