You would need to use eval, but that is probably not the right path. If you have many files for which you need to associate names, how about using a dict:
julia> files = Dict{String,String}()
Dict{String, String}()
julia> files[chr*"file"] = "c:/Users/"*chr*".csv"
"c:/Users/ppp.csv"
julia> files["pppfile"]
"c:/Users/ppp.csv"