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Cement setting times in current weather
I've searched on the internet but I'm having trouble finding 'real
world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? -- Chris Green · |
Cement setting times in current weather
Chris Green explained :
Two to three days seems a reasonable guess but is that for warmer times? Gently - 24 hours, 2 or 3 days it should be OK to walk on normally, providing it is under slabs. |
Cement setting times in current weather
On 20/03/2021 18:59, Chris Green wrote:
I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? Assuming you have got the water content right: Strong enough to walk on, a minimum of one day. Two days is better. Strong enough to work on, about a week. To help curing, cover with insulation - cardboard or proper concrete blankets. That keeps in the heat of the curing and helps to protect from cold weather. -- Colin Bignell |
Cement setting times in current weather
Chris Hogg wrote:
On Sat, 20 Mar 2021 18:59:22 +0000, Chris Green wrote: I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? https://www.cemex.co.uk/using-concre...d-weather.aspx https://www.cement.org/learn/concret...her-concreting Thank you, those are useful. -- Chris Green · |
Cement setting times in current weather
nightjar wrote:
On 20/03/2021 18:59, Chris Green wrote: I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? Assuming you have got the water content right: Strong enough to walk on, a minimum of one day. Two days is better. Strong enough to work on, about a week. To help curing, cover with insulation - cardboard or proper concrete blankets. That keeps in the heat of the curing and helps to protect from cold weather. Thank you. Yes, I hadn't realised that the curing process is slightly exothermic so some insulation helps things along (and stops drying out). -- Chris Green · |
Cement setting times in current weather
On 20/03/2021 18:59, Chris Green wrote:
I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? I laid some slabs to form a step at the beginning of last week when the temperature was expected to be around 8C during the day and above 4C during the night. I put the left over sharp sand/cement mix (4:1) in two piles on a bit of plastic bag. I wasn't too happy with the strength of one of these piles after 20 hours but after 48 hours the second pile seemed really hard. The original mix was on the dryish side and the water used was warm from the hot tap. The step was covered with a tarpaulin or 48 hours. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Cement setting times in current weather
"Chris Green" wrote in message ... I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. Trouble is that acceptably hard and strong is a movable feast. Do you mean hard enough so kids cant graffiti it, or strong enough so you can drive over it ? Even with that last, there is a big difference between being able to drive on it with your car to park it in the garage and big bucket truck or mobile crane etc. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? Yes for walking but not for driving a mobile crane onto it. |
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On Sun, 21 Mar 2021 08:37:36 +1100, %%, better known as cantankerous
trolling senile geezer Rodent Speed, wrote: FLUSH the trolling senile asshole's latest troll**** unread Changed nym yet again, you abnormal senile troll? -- Website (from 2007) dedicated to the 86-year-old senile Australian cretin's pathological trolling: https://www.pcreview.co.uk/threads/r...d-faq.2973853/ |
Cement setting times in current weather
Chris Green wrote:
I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? Almost exactly a year ago, I had some foundations poured ranging from 550 to 850mm depth of concrete, I was a little concerned that there had been some chilly mornings, the supplier said no problem it would be hard enough to walk on overnight, as it happened I didn't visit until 48 hours later and it was by then. |
Cement setting times in current weather
On 20/03/2021 19:34, Chris Hogg wrote:
On Sat, 20 Mar 2021 18:59:22 +0000, Chris Green wrote: I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? https://www.cemex.co.uk/using-concre...d-weather.aspx https://www.cement.org/learn/concret...her-concreting 24 hours is good enough for light loads, It will be crumbly but you can wlak on it. even overnight will show some appreciable hardening. you can test with a finger -- "Women actually are capable of being far more than the feminists will let them." |
Cement setting times in current weather
On 20/03/2021 20:36, Chris Green wrote:
nightjar wrote: On 20/03/2021 18:59, Chris Green wrote: I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times. It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard? I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? Assuming you have got the water content right: Strong enough to walk on, a minimum of one day. Two days is better. Strong enough to work on, about a week. To help curing, cover with insulation - cardboard or proper concrete blankets. That keeps in the heat of the curing and helps to protect from cold weather. Thank you. Yes, I hadn't realised that the curing process is slightly exothermic so some insulation helps things along (and stops drying out). When large concrete dams are being built they have to pour the concrete in 'cubes' in such a way that excess exothermic heat does not weaken the final result.` https://www.youtube.com/watch?v=n9Gy_1Ppw5U |
Cement setting times in current weather
Maximum IQ achieved after 28 days :-)
Andrew On 21/03/2021 08:39, Brian Gaff (Sofa) wrote: How thick is it though? Brian |
Cement setting times in current weather
On 20/03/2021 21:32, alan_m wrote:
On 20/03/2021 18:59, Chris Green wrote: I've searched on the internet but I'm having trouble finding 'real world' practical cement setting times.Â* It's fairly easy to find how long it will be workable and thus when you have to finish a mix. However finding when it will be acceptably hard and strong is more difficult. So, at present, with outside temperatures in the 5 to 10 degrees Celsius sort of range (hereabouts anyway) how long should I be expecting my cement to take before being reasonably hard?Â* I know it's upwards of a month before it has reached most of its final strength but I want to know when I can put weight on slabs supported by concrete and when pointing will be strong enough to walk around on. Two to three days seems a reasonable guess but is that for warmer times? I laid some slabs to form a step at the beginning of last week when the temperature was expected to be around 8C during the day and above 4C during the night. I put the left over sharp sand/cement mix (4:1) in two piles on a bit of plastic bag.Â* I wasn't too happy with the strength of one of these piles after 20 hours but after 48 hours the second pile seemed really hard. The original mix was on the dryish side and the water used was warm from the hot tap.Â* The step was covered with a tarpaulin or 48 hours. I also bricked up a chimney opening this morning after removing a gas fire. As I already had some sharp sand and cement from my previous job I used a 4:1 mix to mortar in some bricks. 11 hours later the mortar is hard, although not fully dry. I put a pile of the mortar I had left over on a sheet of plastic in the outside cold. This pile is still very crumbly so an extra 15C of temperature has made a large difference to the setting time, as expected. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Cement setting times in current weather
On 21/03/2021 22:13, alan_m wrote:
I also bricked up a chimney opening this morning after removing a gas fire.Â* As I already had some sharp sand and cement from my previous job I used a 4:1 mix to mortar in some bricks.Â* 11 hours later the mortar is hard, although not fully dry. I put a pile of the mortar I had left over on a sheet of plastic in the outside cold. This pile is still very crumbly so an extra 15C of temperature has made a large difference to the setting time, as expected. You should use proper sand for brick and blocklaying mortar. Sharp sand is for screeding and rendering, or so I thought. |
Cement setting times in current weather
On 21/03/2021 22:13, alan_m wrote:
I also bricked up a chimney opening this morning after removing a gas fire.Â* As I already had some sharp sand and cement from my previous job I used a 4:1 mix to mortar in some bricks.Â* 11 hours later the mortar is hard, although not fully dry. I put a pile of the mortar I had left over on a sheet of plastic in the outside cold. This pile is still very crumbly so an extra 15C of temperature has made a large difference to the setting time, as expected. Have you made provision for ventilating it? (It's normal to leave an airbrick at the bottom. For good reason) ANdy |
Cement setting times in current weather
On 22/03/2021 19:56, Andrew wrote:
On 21/03/2021 22:13, alan_m wrote: I also bricked up a chimney opening this morning after removing a gas fire.Â* As I already had some sharp sand and cement from my previous job I used a 4:1 mix to mortar in some bricks.Â* 11 hours later the mortar is hard, although not fully dry. I put a pile of the mortar I had left over on a sheet of plastic in the outside cold. This pile is still very crumbly so an extra 15C of temperature has made a large difference to the setting time, as expected. You should use proper sand for brick and blocklaying mortar. Sharp sand is for screeding and rendering, or so I thought. I'm aware of this but it was to brick up a two foot by two foot hole which will be plastered over. I already had the sharp sand and cement from a previous job so I wasn't going to go out and buy another bag of soft/builders sand. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Cement setting times in current weather
On 22/03/2021 22:00, Vir Campestris wrote:
On 21/03/2021 22:13, alan_m wrote: I also bricked up a chimney opening this morning after removing a gas fire.Â* As I already had some sharp sand and cement from my previous job I used a 4:1 mix to mortar in some bricks.Â* 11 hours later the mortar is hard, although not fully dry. I put a pile of the mortar I had left over on a sheet of plastic in the outside cold. This pile is still very crumbly so an extra 15C of temperature has made a large difference to the setting time, as expected. Have you made provision for ventilating it?Â* (It's normal to leave an airbrick at the bottom. For good reason) ANdy Yep, all my bricked up chimneys have a ventilation grill in the room. I've used tinyurl.com/3nsk36yk -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Cement setting times in current weather
On 20/03/2021 18:59, Chris Green wrote:
Two to three days seems a reasonable guess but is that for warmer times? I rendered our yard wall yesterday afternoon, in that i've shuttered it and poured about 2 inch of concrete between the board and the wall. Wondering when I should remove the boards... As soon as it's starting to stiffen, so it 'dries out' exposed and evenly or is it best covered for longer? Any opinions from the group? |
Cement setting times in current weather
On 26/03/2021 11:58, R D S wrote:
On 20/03/2021 18:59, Chris Green wrote: Two to three days seems a reasonable guess but is that for warmer times? I rendered our yard wall yesterday afternoon, in that i've shuttered it and poured about 2 inch of concrete between the board and the wall. Wondering when I should remove the boards... As soon as it's starting to stiffen, so it 'dries out' exposed and evenly or is it best covered for longer? Any opinions from the group? As long as it wont fall off makes sod all difference -- Renewable energy: Expensive solutions that don't work to a problem that doesn't exist instituted by self legalising protection rackets that don't protect, masquerading as public servants who don't serve the public. |
Cement setting times in current weather
On 26 Mar 2021 at 11:58:28 GMT, "R D S" wrote:
On 20/03/2021 18:59, Chris Green wrote: Two to three days seems a reasonable guess but is that for warmer times? I rendered our yard wall yesterday afternoon, in that i've shuttered it and poured about 2 inch of concrete between the board and the wall. Wondering when I should remove the boards... As soon as it's starting to stiffen, so it 'dries out' exposed and evenly or is it best covered for longer? Any opinions from the group? No harm results from leaving it longer. If the concrete was too wet drying the surface wouldn't help anyway. And if the concrete is properly constituted then the longer you leave it the less likely removal will damage the surface. -- Roger Hayter |
Cement setting times in current weather
On 26/03/2021 13:41, The Natural Philosopher wrote:
On 26/03/2021 11:58, R D S wrote: On 20/03/2021 18:59, Chris Green wrote: Two to three days seems a reasonable guess but is that for warmer times? I rendered our yard wall yesterday afternoon, in that i've shuttered it and poured about 2 inch of concrete between the board and the wall. Wondering when I should remove the boards... As soon as it's starting to stiffen, so it 'dries out' exposed and evenly or is it best covered for longer? Any opinions from the group? As long as it wont fall off makes sod all difference Isn't that the problem - determining when its strong enough not to fall off? Leaving a quarter bucket of left over 4:1 mix in a pile recently in the cold probably suggests a MINIMUM of 48 hours and more like twice that before I would be confident enough to start banging around it to get shuttering off. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Cement setting times in current weather
On 27/03/2021 09:45, alan_m wrote:
On 26/03/2021 13:41, The Natural Philosopher wrote: On 26/03/2021 11:58, R D S wrote: On 20/03/2021 18:59, Chris Green wrote: Two to three days seems a reasonable guess but is that for warmer times? I rendered our yard wall yesterday afternoon, in that i've shuttered it and poured about 2 inch of concrete between the board and the wall. Wondering when I should remove the boards... As soon as it's starting to stiffen, so it 'dries out' exposed and evenly or is it best covered for longer? Any opinions from the group? As long as it wont fall off makes sod all difference Isn't that the problem - determining when its strong enough not to fall off?Â* Leaving a quarter bucket of left over 4:1 mix in a pile recently in the cold probably suggests a MINIMUMÂ* of 48 hours and more like twice that before I would be confident enough to start banging around it to get shuttering off. Well, because i'm highly impatient and somewhat reckless I took it off yesterday afternoon and it was OK, it had been in place just under 24 hrs. |
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