Export/Import and Corrupt Block in oracle database

While Doing export backup of database/schema/objects;
If there is a corrupted object, an error will  be written in the export log showing the object that was not exported.
Therefore, no corrupt object blocks will be exported into the export file.

1. Export does not detect all corruptions:
  - does not detect disk corruptions above the high water mark;
  - does not detect corruptions in indexes, or in free or temporary extents;
  - does not detect all corruptions in the data dictionary (the export
     utility does not read all of the data dictionary, so there could still be undetected corruptions in the
     SYSTEM tablespace).

2. Only a Conventional path export is able to detect logical corrupt blocks.
  When using a Direct path export , the data is read from disk directly
  into the export session's program global area (PGA): the rows are
  transferred directly to the Export session's private buffer. This means
  that the SQL command-processing layer (evaluation buffer) is bypassed,
  because the data is already in the format that Export expects.
  Therefore, do not specify the export parameter DIRECT=Y but use DIRECT=N
  which is also the default value for the DIRECT parameter.

Therefore, use a conventional export and not the direct path.