You could probably saturate that link with a single TCP stream -- even without BBR -- by simply choosing the correct send and receive buffer sizes in your test program. (I assume you're using iperf or a similar program to perform your tests.)

BBR and other congestion-control algorithms come into play when the underlying IP network is congested. To test them, you have to have control of the congestion rate of the underlying circuit, which you might not have if you're testing this on an ordinary public IP network.