Volume 7, Issue 10 (November 2010)
Incorporation of Property-Based Testing in Coarse Aggregate Specifications for Pavement Applications
The demand for pavement facilities that can handle increasing loads escalates the need for high quality aggregate material. While once plentiful, quality aggregate sources are starting to diminish. When aggregates are eliminated locally by resource depletion as well as land development that prohibits mining, the cost of construction can rise significantly. The cost of transporting quality aggregate materials from other places that comply with specifications can be very expensive. Coarse aggregate specifications for pavement mixtures for many states are outdated, with some sections dating back to around the 1930s. Specifications do not reflect the current level of knowledge concerning testing methodologies of desirable aggregate properties for pavement applications, especially at the local and low volume level. There is a need to evaluate the quality of aggregates based on the suitability of property-based testing requirements. A better understanding of testing requirements used to evaluate material properties can lead to a better utilization of local aggregate materials and reduce the reliance on diminishing high quality sources. This study investigates what property-based testing requirements have been established in current specifications as well as new areas of testing that need to be developed. A questionnaire of professionals defined a set of testing requirements for different pavement applications, which were then compared to the currently specified testing requirements. The results concluded that gaps exist in how professionals define quality aggregate compared to what current specifications define as quality aggregate. This creates the need for the inclusion of more property-based testing that could better characterize aggregates based on pavement performance. This type of characterization could open up the possibility of utilizing local materials that are normally rejected for lower volume applications.