Hi all,
So my newly laid concrete slab is now just over a week old.
As with anything I often do when I give it a go for the first time I was nervous as you're never quite sure how it's going to end up!
Well no surprise my concrete mixing/finishing skills still need a lot of work because patches of the slab have started to spall and are a bit sandy. I've attached a photo. Probably only 1/4 is affected and it is in small patches not all over.
From various reading and looking at old forum posts and other resources I understand that spalling can be caused by several factors including poor mix, rapid temperature change, finishing too early amongst others.
Temperatures didn't drop below freezing when it was set and they haven't for the last week and it's obviously more than likely my novice finishing or mixing skills.
My main question is this. The slab is for a shed base so cosmetically the spalling is not an issue as it will be covered. There are no cracks or fissures, no voids and the dark area of exposed concrete under the flaked off spall is rock solid. So is the rest of the slab. The flaking portions are probably 3Mm thick max and the underneath does not show any signs of poor setting.
Could this be a surface finish issue and while not ideal would it be ok to just remove as much as possible and leave as it is?
I think my finishing technique was more than likely inadequate but this shouldn't compromise the overall mix I would hope.
Thanks
Daz
So my newly laid concrete slab is now just over a week old.
As with anything I often do when I give it a go for the first time I was nervous as you're never quite sure how it's going to end up!
Well no surprise my concrete mixing/finishing skills still need a lot of work because patches of the slab have started to spall and are a bit sandy. I've attached a photo. Probably only 1/4 is affected and it is in small patches not all over.
From various reading and looking at old forum posts and other resources I understand that spalling can be caused by several factors including poor mix, rapid temperature change, finishing too early amongst others.
Temperatures didn't drop below freezing when it was set and they haven't for the last week and it's obviously more than likely my novice finishing or mixing skills.
My main question is this. The slab is for a shed base so cosmetically the spalling is not an issue as it will be covered. There are no cracks or fissures, no voids and the dark area of exposed concrete under the flaked off spall is rock solid. So is the rest of the slab. The flaking portions are probably 3Mm thick max and the underneath does not show any signs of poor setting.
Could this be a surface finish issue and while not ideal would it be ok to just remove as much as possible and leave as it is?
I think my finishing technique was more than likely inadequate but this shouldn't compromise the overall mix I would hope.
Thanks
Daz
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