Assessment of a Simple Test to Evaluate Concrete Permeability Presenter: Erica Mack Acknowledgements: Peter Taylor, Xuhao Wang

40% the concrete state 20% background Percentage of paved roads within Iowa that are paved with concrete the concrete 40% Percentage of paved roads within the United States that are paved with concrete state 20%

background

1-inch Crushed Limestone methods water cement ratio 0.35 0.40 0.45 0.60 Cement Slag Class C Fly Ash twelve Natural River Sand 1-inch Crushed Limestone unique mix designs

methods six samples per mixture seventy-two total samples Air Permeability Test Drop Absorption Test Compressive Strength Test

methods twenty microliters of water 3 days 7 days 56 days 28 days

results of the mix design The compressive strength is lower when the water-cement ratio of the mixture is higher.

results and analysis A low water cement ratio is expected to yield a lower permeability. A lower permeability will result in a higher drop absorption time. This property was confirmed and consistent across all twelve mix designs.

results and analysis Permeability is expected to be poor when concrete is at a young age, resulting in a low drop absorption time. Supplementing slag as a binder type creates a denser paste, increasing drop absorption time.

results of the air permeability test The air permeability test was conducted to have a direct measurement of the permeability of the samples. Drop absorption time increased linearly with the measured air permeability index.

conclusions Traditional Test Methods Traditional Test Methods The drop absorption test provides permeability results that are consistent with known permeability characteristics of concrete. The drop absorption test is faster and more localized than traditional permeability test methods. Traditional Test Methods Drop Absorption Test Traditional Test Methods Drop Absorption Test

current uses and future goals The drop absorption test is being used to assess roadways within Iowa that are experiencing the common pavement distress of joint deterioration. A classification scale is being developed to provide an indication of permeability after obtaining the drop absorption time of a sample. The drop absorption test has the potential to be of great value to the industry.

thank you Thank you for listening. Special thanks to the Concrete Pavement Technology Center, the Portland Cement Concrete Pavement and Materials Research Laboratory, and Iowa State University.