Like ready mixed concrete, ready mixed mortar is mixed at a plant and delivered to the job in trucks. Use of new extended life admixtures that can retard set for as long as 72 hours make this possible. THE ADMIXTURE THAT MAKES IT POSSIBLE In addition to extending the storage life of mortar up to 72 hours, the admixture improves fresh and hardened mortar properties. The admixture may be a blend of several individual admixtures: retarder; moisture retention agent; water reducer; and air-entraining agent. As with all admixtures, mortar temperature, mixing sequence, mixing time, and mix proportions all influence the effectiveness of extended life admixtures. DOES IT TAKE 72 HOURS BEFORE MORTAR JOINTS HARDEN? When the mortar is placed between masonry units, the units absorb water and admixtures in the water. Removing the extended life admixture from the mortar causes it to assume the setting characteristics of conventional job-mixed mortar. WAYS OF DELIVERING READY MIXED MORTAR It can be delivered in ready mixed concrete trucks, shipped in containers on a flatbed trailer, or mixed at the jobsite by a supplier who uses mobile batcher-mixers.