High temperature deformation investigation of asphalt mixture with nanosized volcanic ash fillers using optical fiber sensor

Abstract

Due to the complexity of asphalt concrete materials and lack of reliable test methods, the high temperature rutting resistance is difficult to be quantitatively expressed. The increasing use of modified asphalt and nontraditional materials makes it even more complicated. This paper introduces an optical fiber Bragg grating (FBG) based equipment for the synchronous 3D strain measurement of asphalt concrete specimen with high resolution. The FBG has high data sampling frequency (up to 300 Hz) and large strain range (10,000 με). The strain measurement accuracy of the FBG can reach 1 με. For the repeatability and accuracy tests in this paper, the maximum strain variances of the proposed equipment were 1.66% and 2%, respectively. Four types of asphalt concrete with nanosized volcanic ash fine fillers have been evaluated through the repeated-load plastic deformation test using the proposed equipment. Through the analysis of the whole process strain data, it is proved that the shape of the strain curve in steady cycle can be independent of the load magnitude and the aggregate skeleton. Therefore, the strain curve can be used to study the mechanism of the generation of rutting and develop indicators for material rutting resistance evaluation quantitatively.