The Collaborative International Dictionary of English v.0.48:

Bituminize \Bi*tu"mi*nize\, v. t. [imp. & p. p. Bituminized;
   p. pr. & vb. n. Bituminizing.] [Cf. F. bituminiser.]
   To prepare, treat, impregnate, or coat with bitumen.
   [1913 Webster]