Delta 20 set retarder was specially developed to retard the extremely fast setting times of amorphous calcium aluminate (ACA) based mixes, such as those based on Calumex SC-A and Calumex XT-20. It provides improved workability without sacrificing strength development or rapid hardening after initial set.
At a dosage of 0.3% initial setting times of Calumex SC-A (when mixed with portland cement at a 1:9 ratio) can be increased from 30 seconds to more than 10 minutes. However, final set still remains within one minute of initial set, providing the best of both worlds.
Delta 20 is a fine powder that quickly dissolves in slurry or that can be added to dry mortar mix to improve characteristics.