Cement and Flyash can be some of the biggest BS loads to be hauled. If you get to the plant and have no trucks in front of you then it's a cake walk, but the waiting can be insane. I've waited down here in Crystal River for hours on flyash, only to miss my appointment time and get stuck in 5 o'clock Tampa traffic. You have your good days and you have your bad, super long days. Keep in mind your time at the receiver pumping and setting up and storing back your equipment will tie you up for atleast an hour on every load.
Make sure you get downtime pay for all the BS that goes along with the job, if they're not going to pay you for that I wouldn't take the job. There's too much time to be wasted in the pneumatic field.