Mahmood Naderi - Engineering Faculty, Imam Khomeini International University, Qazvin, Iran.

The friction-transfer method, which is described in this paper, can be used to measure the in-situ strengths of bituminous materials. From these strengths it is possible to estimate the relative Marshal strengths, using appropriate calibration graphs. In this method a specially devised apparatus fits on to the top of the partial core and is clamped to it. To measure the asphalt concrete strength, a torque is applied using an ordinary torquemeter and the maximum torque or shear stress at failure is calculated. Comparative studies of Marshal strength and friction-transfer tests produced very good correlations indicating that this new method can be used not only to study the suitability of the Marshal test, but to analyze the effects of serviceability conditions such as: freezethaw, wetting and drying, etc. on the behavior of different asphalt mixtures.

Bituminous materials; In-situ strength; Friction-transfer method; Marshal test