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]

WordNet (r) 3.0 (2006):

bituminize
    v 1: treat with bitumen [syn: bituminize, bituminise]