Accepting that there are variables (such as climate), how long would these structures be expected to last? Would they become non-repairable or could replacements of parts (pre-cast panels OR frames) extend their lives? I would be looking at something to last me another 50 years
Anyone in a laboratory knows about formaldehyde for preserving tissues - and it is VERY unpleasant stuff.
I would say Shawn is the better man to ask this question from he has real experience in using concrete. I kind of guessed you would see the sense in using the P boards, just remember to coat with floor wax and they will come off clean If I was to do what you are doing I would not put a beam mid section, understand this method is almost one big beam in itself and you are just putting one beam on top of another, you really gave your own answer to the question, suggesting the Rebar from foundation level goes all the way to the top, what can also be done is; you can inset a piece of 2'' square Coco lumber at the top of the first pour, any scrap wood will do, drill big holes to take the rebar, remove before the concrete has set and you will have provided a key for the next pour, the Tex/Phil guy does not vibrate his forms only hits them with a rubber hammer that is only good on the outside, better to use a form vibrator and that really consolidates it, I used a small Jack hammer electric drill and this worked well, a better job will always be done using a mixer and not by hand mix, use the cheaper Pozzolan cement and you will get less thermal cracking, anyone that says to use the Premium Portland, need to do some research on this, a couple of others things to note, the bottom of the forms tend to swell outwards with the weight of the concrete make sure it is well braced, use slightly less chips in the first 12 inches of pour as some to migrate to the bottom especially if it is vibrated, be careful of the water content as a very rough guide, when the mixer is tipped to empty the batch should rise to meet the mouth of the mixer and the top of this needs to be knocked off to get the rest out. I guess Shawn in the only one to advise you on the cold joint and what material if any is available for this, it must be wetted for sure maybe with some cement in the water? Hope this helps
Curing the Concrete, form boards should not be removed for at least 48hrs after that you have to keep it wetted or cover with plastic, concrete drying out too quickly is not good, perhaps even leave the form on for a whole week? you will be surprised how hot it will be in the first 2 days then it slowly cools, I have seen forms removed the next day but I would not chance that, back to the question of Cold Joints, a CHB wall is just full of them? Providing a key on the bottom section have it all wetted down before the top section is poured, vibrate well (but do not over vibrate) and it is unlikely you will have the typical voids like in the pictures I posted, know this even a badly made Concrete wall is sure to be 10 times stronger than one of CHB, just do the best you can and you will have No Wucking Furries
A 20m long wall is a long span without any corners in it, may fall over if the footings are small. May want to add a few corners, notch is back 500mm for a few meters then back in line again. Add a planter in the recessed section. Not sure if that made sense.
There will be columns along the wall but a poured wall firmly attached to the footing should be stable enough... the footing will be twice the width of the wall, I will also turn the wall at both ends for 1 meter before transition to smaller fencing...
You can use snap ties for this. They work by pulling against the opposing forces on either side of the form. Very little bracing is required with this method. Later the ends are "snapped" off about 1-1/2 inches in the concrete and patched.. Another method is to cut pvc conduit the thickness of the wall and use all thread through it to hold the forms together. The pvc holds the forms apart and the all tread holds them together. The pvc remains in the wall and the all thread is reused. Here they are pouring an 8 foot wall in one shot. They do not seem to be worried about the concrete segregating.
Sir I would like you to consider this; A CIP concrete wall will have much more weight in it that a CHB one does, they are full of air pockets and the blocks are lighter than concrete, in UK the rule of thumb is; the footing should be 6'' either side of the wall minimum depending on soil conditions? If it were me I would put in a 24''wide for a 6'' Wall, 20'' for a 4'' and have it 8''to10'' deep with lots of steel in it, It would help me sleep better? The best advice for this is likely to be from Shawn, Ozzyguy is also pretty good on construction advice.
Sure, I am a belts and suspenders kind of guy and will make the footing with a rebar beam inside and will make it much wider than the wall, also thinking about making the upper 4 ft 3/4 the width of the lower 4 ft.... kind of you to be concerned but will follow all safety rules.... also will follow Texas Filipino tip to pour a layer and let if firm before pouring the next, Will only pour 4 ft total so not to worried about blowout ...
