If you have your file located locally then you can use install.packages() and then set repos = NULL :
install.packages(path_to_file, repos = NULL, type="source")
path_to_file will represent the full path and file name:
- On Windows it will look something like this: "C:\\RJSONIO_0.2-3.tar.gz".
- On UNIX it will look like this: "/home/blah/RJSONIO_0.2-3.tar.gz".