The state convict road force shall be guarded when working on the roads and in making road materials, and when being transported to and from the penitentiary, by guards detailed by the warden, who shall designate one guard as the superior, and the other or others as assistants. The state guard and assistants shall obey the rules prescribed for prison camps. Any guard or assistant not obeying such rules shall, on the recommendation of the superintendent or engineer in charge of the work, be immediately recalled, and some other person detailed in his stead. The wages of each guard, superior and assistant, shall be fixed by the road commissioner. All guards and prisoners shall be under the direction of the warden, or his authority, and shall work not to exceed sixty hours per week, and each prisoner shall be paid for each work day, not to exceed ten hours, the sum of 10¢ and for time in excess thereof 10¢ per hour for such excess time worked.