What is the methods of concrete curing or is it only water curing ?

1. By applying curing compound on the surface of the fresh concrete, to prevent rapid drying of the concrete and allowing to attained the maximum strenght at a designed period of time.

2. Steam Curing - used when the strength of concrete needs to be attained at a very short time. Used in casting of Pre tension girders (for mass prodcuction of girders). The 80% strenght of concrete is attained at 24 hrs.  And it is enought to release the strand allowing the girders to be removed at the casting area and prepare for another batch.

3. Curing by water sprinkling - the surface the fresh concrete will be covered with burlap and wetted with water by spray. in this way the surface of concrete is wet throughtout. Springkling shall be at a minimum interval so that in no time the surface will not dry until the desired strenght of concrete in attained.

4. Curing by water ponding - Usually on the surface of floor slab with big area.

Cement hydration is what transforms concrete mixture to hardened concrete. Hydration is the cement reaction with water. The curing methods try to replace the missing moisture and/or prevent drying. Admixtures can accelerate hardening  but still the fresh concrete must maintain its moisture. The covering concrete methods still need water to keep wet the covering materials. Steam method cannot be consider as steam is water. Shading of concrete surfaces is not enough without wetting...

So, the only without-water-method that I am aware of, is curing with chemical applied on the concrete's surface which prevents evaporation.

I am interested to learn if there are other methods...

Of course concrete curing is water curing but there are some other materials for concrete curing, such us concrete hardening accelerator