AI just released a document that illustrates inaccuracies and manipulation of asphalt thickness design and cost analysis within “Concrete Pavement Analyst (CPA)” – a computer program developed and distributed by the National Ready Mix Concrete Association to help consultants design parking lots.
Our 11-page “Setting the Record Straight” document can be downloaded now. While CPA refers to Asphalt Institute design methods for their asphalt pavement designs, CPA does not replicate them or produce results that are comparable. In fact, CPA produces asphalt designs that are up to double the required asphalt thickness relative to actual AI methods.
CPA then takes the overdesigned asphalt section and their “comparable” concrete section and performs Life Cycle Cost Analysis (LCCA) on both designs. The LCCA within CPA is full of biased assumptions and defaults against asphalt, such as an overly aggressive asphalt rehabilitation and maintenance schedule. All the biases within CPA lead to increased thickness and increased cost for asphalt. Details can be found by downloading the AI document.
Our message is clear to consultants that are being presented with CPA: It is not wise to use a concrete association’s software to design and analyze an asphalt pavement because the results will be skewed in concrete’s favor.