CTRE  en route

Summer 2007

CTRE en route is published twice a year to inform readers about CTRE's projects and programs.

Address: CTRE, 2901 S. Loop Drive, Suite 3100, Ames, IA 50010

Phone: 515-294-8103
FAX: 515-294-0467

Website: www.ctre.iastate.edu/

CTRE Communications:
Marcia Brink
CTRE en route editor:
Michele Regenold

CTRE is an Iowa State University center.

Iowa State University: Becoming the best

CP Tech Center lab scores well

A computer and a variety of lab equipment set up on 2 desksEquipment for the Rapid Chloride Permeability test.

Several small concrete samples in a pot of water on a burnerConducting a boil test.

In June 2007, Kansas Department of Transportation (KDOT) Concrete Research Engineer Rodney Montney invited 5 concrete research labs to take part in a “round-robin” set of tests. The objective was to compare test results from different labs. The test results should be similar; however, they may be influenced by the different labs’ operations, technicians, and equipment.

The CP Tech Center’s lab results were right on the average. Lab manager Bob Steffes said, “These results show that our technician and equipment are doing good work.”

About the testing

KDOT created identical concrete samples:

  • 6 4”x8” concrete cylinders with 5% silica fume and
  • 6 4”x8” concrete cylinders with 7% silica fume.

Each lab was ordered to follow the exact same test standards and procedures covering 2 different tests:

  • Rapid Chloride Permeability (ASTM C1202-97) and
  • Volume of Permeable Voids (Boil Test) (ASTM C 642).


KDOT analyzed all the labs’ results from the 2 tests.

Test performed Cylinders tested
(3 per test)
Range of results Average results from all labs CP Tech lab results
Volume of Permeable Voids(%)(ASTM C 642) 5% silica fume 10.3 % to 8.9 % 9.7 % 9.7 %
7% silica fume 10.0% to 8.2% 9.0 % 9.2 %
Rapid Chloride Ion Permeability (Coulombs) (ASTM C 1202-97) 5% silica fume 3258 to 1847 2420 2446
7% silica fume 3054 to1727 2251 2288

These results show that the CP Tech Center lab performance is very well centered within the range of results from all the participating labs.

Congratulations to Jeremy McIntyre, CP Tech Center lab technician, and Bob Steffes, CP Tech Center lab manager.