What is a hydraulic cement and are there chemicals other than calcium chloride that add to the rapid set of concrete?
Hydraulic cements are cements which are capable of setting and hardening under water. Lime mortars cannot do this as they need the carbon dioxide of the air to change from the hydrated lime of the mortar to calcium carbonate. Among the commercially available hydraulic cements are portland cements, blast-furnace slag cements, portland-pozzolan cements, white portland cements and alumina cement. In addition to calcium chloride, other chlorides will act to accelerate setting and hardening of concrete. They are not as effective and economical as calcium chloride. A few silicates will also accelerate setting. Some of these are marketed by admixture manufacturers.