Attic flue vent pipe...asbestos? If so, what should I do?
Searching online using the phrase ""Transite flue pipe" leads to a large number of hits that indicate this type of pipe is for sure an asbestos cement pipe. It does need to be handled as a hazardous material when working with it and removing it. 

Transite piping was commonly used as a flue pipe and chimney liner for gas appliance venting. It has had to be discontinued from use because the inside of the pipe would degrade from age, use and temperature changes and then start to flake off. With enough flaking the pipe could become blocked and cause serious problems with gas appliance back drafting. 

Check with local requirements with regard to disposal requirements for this material.