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

•An optical FBG based synchronous 3D strain measurement equipment is introduced.•Elastic, viscoelastic and plastic strain in each cycle can be analyzed separately.•Four types of asphalt concrete with nanosized volcanic ash were evaluated.•Indicators from the steady strain curve can evaluate material quantitatively.•Mechanism of the generation of rutting has been analyzed.