A recent interlaboratory study was conducted to generate single-operator repeatability and multi-operator reproducibility statements that can be included for guidance in C1781. This work was conducted at Middle Tennessee State University and was analyzed under ASTM ILS # 1012. In this study, test pads of permeable unit pavement systems were constructed with 14 different concrete paver types and each of the 14 different pavement systems were tested with three different sized drainage aggregates meeting the grading requirements of Size Numbers 8, 9 and 10 in accordance with ASTM C33-13, Standard Specification of Concrete Aggregates  (which are identical to those in ASTM D448, Standard Classification for Sizes of Aggregate for Road and Bridge Construction ). A total of 42 different paver unit/drainage aggregate systems were tested. Note that while Size Number 10 aggregate is not recommended by ICPI for use as a drainage aggregate because of the reduced permeability of systems when this aggregate is used, it was included in the inter-laboratory study to simulate permeable systems with reduced infiltration rates due to partial clogging from sediment over time. This was done to check the validity of the test method over a wider range of infiltration rate values. Test boxes were built for each paver unit/drainage aggregate system and mounted together on a permeable subbase layer atop silty soil. The testing was done by two operators and one additional person recording the time for all events. Each operator conducted duplicate measurements at two locations for each paver unit/drainage aggregate system resulting in a total of eight measurements per paver unit/aggregate system; four for Operator 1 and four for Operator 2. Overall, the infiltration rate values for all the tests ranged from 30 to 1600 in./h. Based on the statistical analysis of the data, three new precision statements are being proposed to be added to Section 11 the first on single-operator repeatability, the second on multi-operator reproducibility and the third on the expected difference in measured infiltration rates at two different locations on the same pavement. Further information on the testing and analysis of the data including a draft of the section on Developing a Precision and Bias Statement from an upcoming ASTM symposium paper and the ASTM ILS analysis can be requested from either Kevin Shanahan at email@example.com or Craig Walloch at firstname.lastname@example.org.
Keywordsclay paving units; concrete grid paving units; concrete paving units; infiltration; permeable; unit pavement systems; water;
Ballot Item Approved as C1781/C1781M-2014 and Pending Publication