This is a common question, asked by many.
We all have seen, Almost everyone working at project site, do insist to keep on curing by pouring water, wrapping concrete surface with hessian cloths etc.
Do the poured water really increase the strength of concrete?
What if, i dont cure concrete?
Lot of such questions comes in mind of many peoples.
A bad Concrete can be turned into a good Concrete by doing proper curing and A good Concrete Becomes Bad if we don't cure it properly.
What actually happens in concrete, which need to be taken car?
We all are familiar with a term called hydration, It's a chemical process in which cement react with water and forms a strong bonding in ingredients.
During this process, heat is generated which cause water to get evaporated from its core.
Concrete do not required additional water to complete the hydration process, Design water quantity is sufficient to take care of it.
But if water gets evaporated from its core, the process of bonding stops and it never restart again even if we pour the water on its surface (Bad concrete can achieve good strength, if we do not allow to get this process stop)
OK, i understood it, then why we keep on poring water on its surface?
Water acts like a coolant, which normalize the surface temperature of concrete, due to which evaporation losses stop (If a good concrete not cured, means its temperature is not controlled due to which water from core gets evaporated, it will turn into a bad concrete).
Its like coolant in our vehicle engine, if coolant is not there or insufficient, it will take down the engine and you cant move with that vehicle unless you correct it (Sadly we cant correct it after break-down or stopping in concrete bonding, Its a good subject of research and scientist are trying to achieve a self repairable state by introducing bacteria's in it. You can read more about it by clicking here).
Poured water does not go inside of concrete nor it take any part in hydration process ( Its again a subject of research, though we say concrete is impermeable, its not. it have some porosity and i don't know if it take parts in any reaction or not. Cement particles can take part in chemical reaction with water at any time, provided they have access to water which is seeping in. Mostly it don't because incomplete hydration block the way of water to cement particle. Even if reaction takes place its a very limited and may not contribute to strength gain or bonding).
There are many alternative method's of curing available, which works on same principle. Do not allow the water from concrete to get out from it, hence ensure full hydration in cement particles.
like covering the concrete surface by applying water base, wax base and resin base compounds, which do not permit the escape of water from it.
To ensure the proper curing of concrete we can left the form in place for columns and beams to avoid the evaporation losses (Subjected to project completion schedule and available formwork materials).
Evaporation losses not only happens due to core temperature but also due to a atmospheric temperature, winds etc.
In fresh concrete we had seen a cracks due to shrinkage of concrete.
This happens due to the atmospheric temperature at surface of concrete which evaporates the water from surface thus leads to crack on the surface (More cracking occurs in summer compare to winter).
To avoid such cracks we can implement following curing ways;
1. If the environment is windy (Mostly at coastal and high rise areas) , we can cover the slab top by hessian cloth or polythene sheets after finishing the surface.
2. Curing by sprinkling water should be started immediately after initial setting of concrete (Normalize the atmosphere).
Important : In a slab which are open to sky, we should re-trowel the surface, this will ensure;
1. Sealing of shrinkage cracks and all pores on concrete surface.
2. You have achieved a 99% water proof concrete surface.
If you have any query on it or want to say thank, you can say it by replying to this thread.
We all have seen, Almost everyone working at project site, do insist to keep on curing by pouring water, wrapping concrete surface with hessian cloths etc.
Do the poured water really increase the strength of concrete?
What if, i dont cure concrete?
Lot of such questions comes in mind of many peoples.
What actually happens in concrete, which need to be taken car?
We all are familiar with a term called hydration, It's a chemical process in which cement react with water and forms a strong bonding in ingredients.
During this process, heat is generated which cause water to get evaporated from its core.
Concrete do not required additional water to complete the hydration process, Design water quantity is sufficient to take care of it.
But if water gets evaporated from its core, the process of bonding stops and it never restart again even if we pour the water on its surface (Bad concrete can achieve good strength, if we do not allow to get this process stop)
OK, i understood it, then why we keep on poring water on its surface?
Water acts like a coolant, which normalize the surface temperature of concrete, due to which evaporation losses stop (If a good concrete not cured, means its temperature is not controlled due to which water from core gets evaporated, it will turn into a bad concrete).
Its like coolant in our vehicle engine, if coolant is not there or insufficient, it will take down the engine and you cant move with that vehicle unless you correct it (Sadly we cant correct it after break-down or stopping in concrete bonding, Its a good subject of research and scientist are trying to achieve a self repairable state by introducing bacteria's in it. You can read more about it by clicking here).
Poured water does not go inside of concrete nor it take any part in hydration process ( Its again a subject of research, though we say concrete is impermeable, its not. it have some porosity and i don't know if it take parts in any reaction or not. Cement particles can take part in chemical reaction with water at any time, provided they have access to water which is seeping in. Mostly it don't because incomplete hydration block the way of water to cement particle. Even if reaction takes place its a very limited and may not contribute to strength gain or bonding).
There are many alternative method's of curing available, which works on same principle. Do not allow the water from concrete to get out from it, hence ensure full hydration in cement particles.
like covering the concrete surface by applying water base, wax base and resin base compounds, which do not permit the escape of water from it.
To ensure the proper curing of concrete we can left the form in place for columns and beams to avoid the evaporation losses (Subjected to project completion schedule and available formwork materials).
Evaporation losses not only happens due to core temperature but also due to a atmospheric temperature, winds etc.
In fresh concrete we had seen a cracks due to shrinkage of concrete.
This happens due to the atmospheric temperature at surface of concrete which evaporates the water from surface thus leads to crack on the surface (More cracking occurs in summer compare to winter).
To avoid such cracks we can implement following curing ways;
1. If the environment is windy (Mostly at coastal and high rise areas) , we can cover the slab top by hessian cloth or polythene sheets after finishing the surface.
2. Curing by sprinkling water should be started immediately after initial setting of concrete (Normalize the atmosphere).
Important : In a slab which are open to sky, we should re-trowel the surface, this will ensure;
1. Sealing of shrinkage cracks and all pores on concrete surface.
2. You have achieved a 99% water proof concrete surface.
If you have any query on it or want to say thank, you can say it by replying to this thread.
