System and method for conditioning and detection of moisture damage in asphalt mixes

Abstract

Apparatus and methods for detection of susceptibility to moisture damage for asphalt mixes. A sample of asphalt mix is placed inside a chamber, which is partially filled with water. An increased air pressure is applied to the chamber. A controlled evacuation of the water from the chamber takes place while the increased pressure is maintained in the chamber. Pressure is released from the chamber and water is returned to the chamber. The cycle is repeated a predetermined number of times. Changes in conductivity and turbidity of the water may be monitored to indicate mixture stripping. When a chosen number of cycles of a pressurized emptying and filling of the chamber is complete, the asphalt sample is removed from the chamber and tested against a controlled sample. The test procedure adapts itself readily to a dual chamber design so that two samples may be tested simultaneously. A vacuum may also be applied to the chamber in addition to pressurizing the chamber. The action of forcing water into a sample and allowing it to bleed out of a sample creates pore pressure and stresses the sample in a way that closely simulates the action of a tire passing over wet pavement. Computerized controls may be used to automate the procedure and to record and display data from sensors.