WAS TRAVELING APPROXIMATELY 55 MPH DOWN A STATE HIGHWAY. AFTER COMING AROUND A BLIND CURVE, CAME UPON STOPPED TRAFFIC DUE TO ROAD WORK. APPLIED PRESSURE TO BRAKE PEDAL WHEN PEDAL WENT SOFT AND DEPRESSED ALL THE WAY TO THE FLOOR. AFTER RELEASING BRAKES AND PUSHING AGAIN STILL HAD NO BRAKES. HAD TO SWERVE OUT OF ROAD-WAY TO AVOID REAR ENDING MULTIPLE VEHICLES. AFTER RUNNING OUT OF ROAD, HIT 2 CULVERT PIPES ALONG WITH ROAD WORK SIGNAGE, FINALLY BRINGING THE TRUCK TO A STOP IN A RESIDENTIAL YARD. TRUCK BRAKE LINES FOR FRONT BRAKES HAD CORRODED AND RUPTURED CAUSING THE INCIDENT. FURTHER INVESTIGATION INTO THIS MATTER SHOWS AN APPARENT ISSUE WITH THIS MODEL GMS FOR BRAKE LINE CORROSION THAT GM HAS FAILED TO ADDRESS THROUGH THE RECALL PROCESS.