Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. The dataset collected by ATLAS in LHC pp collisions at $\sqrt{s}$ = 8 TeV is used to perform a variety of such measurements. In the SM the top quark is predicted to decay almost exclusively into a W boson and a $b$-quark. Measurements of the W-helicity and spin correlations in $t\overline{t}$ production are presented as well as new measurements of CP asymmetries in b-hadron decays using top-quark events. As it may be significantly enhanced by the presence of new physics, the $t\overline{t}$ production charge asymmetry is measured inclusively and differentially in the lepton+jets and dilepton channels, including a dedicated measurement for highly boosted top quarks. The first direct ATLAS measurement of the top-quark width is presented.