Microsoft SQL Full & Incr Backup Transaction Log not removed

Hi

we have Microsoft SQL 2008 server and Backup Exec 2012 server.

we have set Full Backup of Microsoft SQL Server databases only on Monday 2 PM and Incremental Backup Tue to Friday 2PM.

Today (on Monday 1 apr 2013 at 2pm) Full backup run successfully but when i go to the data folder transaction logs are still their and not reduced the size.

what should i do to remove the transaction logs once the full backup done.

or i ;m doing anything wrong. next backup will be incremental and on tuesday 2 apr 2013 at  2PM

Regards

Devang