Anisotropy of field-compacted asphalt concrete material

This note presents a study to quantify the degree of anisotropy induced in situ by the compaction equipment. Large asphalt concrete samples were cut from the field and sawed in the laboratory to give prismatic specimens 200 X 80 X 80 mm(3). The specimens were tested in all directions, at 40 degrees C, using low sinusoidal load. The dynamic modulus obtained at different frequencies was used as the indicator of anisotropy in the three principal directions. Analyses of variance were conducted. They indicated that the material is not isotropic, but rather cross-anisotropic.