I don't think ACI has a Standard on maturity testing. There are several ACI reference publications on accelerated curing and the relationship to maturity testing.
Why is the ASTM standard not adequate for the application?
My firm performs maturity testing based on the ASTM C1074 standard, and I have been asked before by clients if there is an applicable ACI standard. I feel that the ASTM standard is adequate, but I'm just trying to make all of my clients comfortable with the procedure.