Emmitt Smith's accused of being a total asphalt -- and screwing a concrete supply company out of nearly $50k worth of cement ... this according to a new lawsuit obtained by TMZ Sports.
Smith -- besides being a NFL legend -- is also the head of Emmitt Smith Enterprises which is the parent company to EJ Smith Supply ... a construction company based in Dallas.
But according to a new lawsuit, EJ Smith ordered $46,448.65 in product from Redi-Mix Concrete last summer -- and never forked over the cash.
Now Redi-Mix is going after the dough ... and they've personally named Emmitt in the lawsuit ... as well as EJ Smith Supply.
We reached out to #22 for comment -- so far, no word back.