Disclosed herein are settable compositions and methods of using settable compositions in a wellbore. In one embodiment a method of introducing a settable composition into a wellbore is described. The method comprises providing a settable composition comprising pumice, hydrated lime, a set retarder, and water. Introducing the settable composition into a wellbore. Allowing the settable composition to remain static in the wellbore, wherein the settable composition remains in a pumpable fluid state for a period of about 1 day or longer while static in the wellbore.