I renovate & flip houses in the Houston area, it is not as easy as shown on TV. I am working on a house built in 2002 where the prior owner poured dry concrete mix down the stand-up shower drain as part of his retaliation at the bank forclosing. I have removed the residual concrete in the top 4 inches of the drain and first 90 bend but am looking for advice on how to efficiently get the rest of the hardened concrete out of the section that is past the second 90 degree turn. I am not sure if I have a P-trap or running trap under the slab connection to the main sewer line since there is an adjacent bathtub.

Does anyone have advice short of jack hammering up the slab? Is there any drain tool that can chip or grind away the concrete inside the pipe since it is not totally rock hard?