Volume 3, Issue 4 (April 2006)
Dynamic Modulus Testing of Thin Pavement Cores
A novel method of testing thin surface cores using the dynamic (complex) modulus test is proposed that utilizes composite mechanics theory. Rectangular specimens are sawed from the round surface layer cores, and the sawed blocks are simply stacked horizontally without bonding. Two hydrostone caps are made to provide flat and smooth loading ends, as well as to restrain the blocks from moving during loading. Two Linear Vertical Differential Transformers are attached 180° apart to the flat uniform side of the horizontally stacked cores to obtain the strain response without measuring over the joint of the cores. The advantage of this approach over the diametral loading mode, used for resilient modulus testing, is that it provides homogenous testing conditions, which gives direct access to stress and strain and, therefore, constitutive equations.