Since the importance of knowing passive layer of steel is the reason of this video, Can U team set up another Cylindrical Concrete which MildSteel reinforcement bars or/and stressed Strand wires inside concrete sample? May be, some additional actual core sample taken from Working Structure to be used for understanding Carbonation Behaviour to Steel Bars bonding inside concrete... Thank You.... Add one sample which represent to Surface Exposures in extreme condition such Under sea water concrete... T. Q... .
Good one sir..Is it should be a freshly opened samples??I think, if we are keeping more time in environment after cutting,then we can't identify the carbonation.
@Kiran Ram You can measure the calcium hydroxide content in the concrete with XRD. You can also use Xray CT and you can see a difference in the X-ray absorption.
Great video! Too bad they only touched on the negative effects.... I found that due to the formation of a calcium carbonate layer the porosity also decreased and compressive strenght increased when compared to reference. Wish we were given fun assignments like these during my degree.
Thanks Michiel, You are right that there can appear to be some benefits during lab testing but we don't always see these in the field. The areas of higher stress in a concrete structure will cause more calcium hydroxide dissolution. The limestone that forms will then be in areas of low stress. This means that the porosity changes are quite variable and depend on the structure. Also, the areas around the reinforcing steel tend to be the highest stressed and so they will see the worst impacts of carbonation. The pores that fill are the large pores and not the small ones. This means the pores are still continuous and the gas permeability doesn't change that much. While there can be some increase in strength from the formation of the limestone it is variable and again depends on the stress in the structure. In the field structures that I have looked at, I see nothing but negatives from carbonation. I do agree though that there can "appear" to be improvements in unstressed lab tests. Thanks so much for the comment!
I for one really dislike the weird video effect you're using. I think stuff in the background would be less distracting than this "infinite white" look.
Thanks, I have thought about putting things in the background but then they get in the way of the words and figures that I want to show. Maybe I will play around with some other backdrops.
Could you raise up your camera some? I love the videos, but staring at your nose-hair for the length of it makes it much harder to watch. Lifting the vantage point would fix most of that..
My review is this is a go. It does not punish anyone. In fact one obtains a harder concrete in half the thickness. This should go viral.
Sir you are one of the best teacher I have encountered . Such energy !!!! Kudos
Thank you so much!
Isnt it just reacting with calcium hydroxide in the matrix to form limestone calcium carbonate. Like old lime cement does?
Great video. Could you explain how carbonation affects on the strength of concrete?
Can you please tell me the test standard that you've followed?
How does one measure the actual amount of carbon dioxide which has been absorbed ?
Since the importance of knowing passive layer of steel is the reason of this video,
Can U team set up another Cylindrical Concrete which MildSteel reinforcement bars or/and stressed Strand wires inside concrete sample? May be, some additional actual core sample taken from Working Structure to be used for understanding Carbonation Behaviour to Steel Bars bonding inside concrete...
Thank You....
Add one sample which represent to Surface Exposures in extreme condition such Under sea water concrete...
T. Q...
.
Good one sir..Is it should be a freshly opened samples??I think, if we are keeping more time in environment after cutting,then we can't identify the carbonation.
Ram - Yes the concrete has to be sprayed right away with the solution.
@@TylerLey Sir,
What are the other methods for determining the carbonation depth in concrete??
@Kiran Ram
You can measure the calcium hydroxide content in the concrete with XRD. You can also use Xray CT and you can see a difference in the X-ray absorption.
@@TylerLey Thank you Sir..
Great video! Too bad they only touched on the negative effects.... I found that due to the formation of a calcium carbonate layer the porosity also decreased and compressive strenght increased when compared to reference. Wish we were given fun assignments like these during my degree.
Thanks Michiel,
You are right that there can appear to be some benefits during lab testing but we don't always see these in the field. The areas of higher stress in a concrete structure will cause more calcium hydroxide dissolution. The limestone that forms will then be in areas of low stress. This means that the porosity changes are quite variable and depend on the structure. Also, the areas around the reinforcing steel tend to be the highest stressed and so they will see the worst impacts of carbonation. The pores that fill are the large pores and not the small ones.
This means the pores are still continuous and the gas permeability doesn't change that much. While there can be some increase in strength from the formation of the limestone it is variable and again depends on the stress in the structure. In the field structures that I have looked at, I see nothing but negatives from carbonation. I do agree though that there can "appear" to be improvements in unstressed lab tests.
Thanks so much for the comment!
Great question!
It can be very helpful to stiffen the concrete but the clay will lose water during hydration and cause a lot of shrinkage.
Nice vedio 👌
Come on man. You're making me read? the spoken word trumps the written word now. This is the 21st century.
I for one really dislike the weird video effect you're using. I think stuff in the background would be less distracting than this "infinite white" look.
Thanks,
I have thought about putting things in the background but then they get in the way of the words and figures that I want to show. Maybe I will play around with some other backdrops.
Could you raise up your camera some? I love the videos, but staring at your nose-hair for the length of it makes it much harder to watch. Lifting the vantage point would fix most of that..