A portable FWD for determining in-situ asphalt layers moduli

In-situ tests on asphalt pavements were carried out to verify the capabilities of the new portable FWD device. It was found that new device requires additional testing on the asphalt surface after coring the asphalt layers to their far bottom. This type of double testing enabled the derivation of the in-situ asphalt layer modulus, using a straight forward backcalculating technique together with a correction factor, depending on the ratio of the asphalt layer thickness to it expected modulus. The results of this derivation were compared with those coming from the conventional FWD-Modulus testing or the laboratory indirect tension tests performed on in-situ asphaltic cores. It was concluded that encouraging results were gained only from the double pfwd testing, as opposed to the conventional FWD-modulus testing.