This is brought as part of the atonement process for a Nazirite who becomes impure: Nedarim 9b
The korban asham of a nazir is brought "for nothing," because it provides neither purification nor atonement: Keritot 27a
Why doesn't the korban asham of a nazir have a minimum value: Keritot 27a
If it was Slaughtered without intent for its dedicated purpose: Menachot 48b
If it was slaughtered when too young or too old: Menachot 48b
Is this considered a "voluntary offering": Temurah 14b
Bringing such an offering on an altar outside the Temple: Temurah 14b
The meat goes to a kohen: Zevachim 44b