Curing for concrete/ glue is when the cement/ glue dries. Dry cement becomes a glue when water is added to it and it becomes wet. The more water in the cement, the longer it takes to dry/ cure, and the stronger it is, and the less likely it is to crumble or crack/ break.
Cement dries/ cures faster in warm dry conditions and is more likely to break, crumble or fall apart if made in hot climates or when the temperature is above 20C. In hot climates, you need to make a wet concrete mix so it has more water and takes longer to dry. This wet mix will take longer to cure and give a stronger cement.
You can also sprinkle water on the cement mix while it is curing and this can extend the curing process so it takes longer to dry and gives a stronger concrete.
If you want to do this in Thailand, try to put the concrete mould in a cool room where they keep food or an air conditioned room. And add plenty of water. Have the plastic lid on the container too, this will help keep moisture in the mix.
Personally, I would just look for some dry limestone rocks and use that. Or sneak down to the beach and grab some limestone from there.
