No! Not normal.
Most root canals are completed in 1-2 visits.
Yours is obviously difficult or presents some complication. You are lucky your dentist is conscientious enough to spend 4 visits treating you for a procedure he likely only expected to spend 1-2 visits on. He/she seems to be trying to do the best job possible, while frustrating for both of you, you will be the beneficiary via the best poss. Outcome.