  We study in a model-independent way anomalous CP-violating tbW effective
couplings that might arise from new physics in the processes pp-> tW^- X and
pp-> tbar W^+X, followed by semileptonic decay of t and tbar. These processes
have a dependence on effective tbW couplings both in the production process as
well as in the decay of the t or tbar. We propose several CP-violating
asymmetries constructed out of variables in the two processes, including t and
tbar polarization, and energy and azimuthal angles of the decay particles. We
find that it is feasible to probe a certain CP-violating combination of
anomalous couplings at the per cent level at the LHC for centre-of-mass energy
14 TeV and an integrated luminosity of 10 fb^{-1}.
