You can repair your corrupt RAR file manually. It is not a big process, it involves very easy steps. The steps are:
[li]Open WinRAR application
[/li][li]Click on file, and then select open
[/li][li]A find archive window will be opened, select corrupt zip file from your system
[/li][li]Click on open button
[/li][li]Repairing File Name.zip will be opened
[/li][li]Click on browse to save repaired file at desired location
[/li][li]Check Treat the corrupt archive as ZIP box, and then click OK
[/li][li]After corrupt ZIP archive is repaired, click on close.
If your file is highly corrupted and you need to use software then you can use additional software. I am recommending because i have used software to repair my PDF file. My PDF file got corrupted due to virus attack.