hi Rick
you can't leave it like that
you have to tell us how the last column compars to the first -- surface voids, wobble, etc
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hi Rick
you can't leave it like that
you have to tell us how the last column compars to the first -- surface voids, wobble, etc
Hi Ian. The last post was tapped a great deal, almost constantly. I did not see much difference. It still had many air bubbles. It was the strongest and did not wobble as it was a 1:3 mix. The one with the least air bubbles was the first post which was made of wet mixes, ones that I was unhappy with as I thought the mixes too sloppy.
If I build the big project I will 1) make mixes 1:3 2) make the mixes a bit wet. 3) mount the posts on square pillars about 900 mm high to reduce wobble. 4) make the posts 1500 mm apart. 5) tap constantly.
Hi RickQuote:
Originally Posted by rick_rine
diagnosing from a distance is always tricky ...
1) It looks like a 1:3 mix is the choice in respect to eliminating "wobble"
2) given your vibration technique -- external taping of the form -- a wet mix is preferred to a dry one
3) there's no reason to have short columns -- I rather like your slender trial columns -- the wobble is mostly due to a mix with too little strength
4) I can't comment on the column spacing -- with the right strength concrete this will mostly be an issue of aesthetics
Attachment 293893 Put points on the beams. I had half a dozen cans of interior paints in the shed with a bit left in them. Mixed them all together to make four litres and sprayed it today. Looks great. Yes I know it is interior and inferior paint. I'm not worried. The vine will cover it.
I am very proud and thanks for your help and support people.
Having trouble uploading photos but I thought I would share my new test pergola. This one has an 800 mm high square base which will reduce the sway in the posts. Also the posts are closer at 1.5 m centres. I reverted to standard gravel and sand mix 3:1 gravel:cement. I used a mechanical vibrator in the posts and in the base. One thing I overlooked was to tie down the base. What happened to the first one is that the concrete lifted the formwork up off the foundation. This oversight was easily fixed with the remaining posts. There is a photo of the first pergola as it is now and the work in progress on the new one. There are more air pockets in these posts, probably because, as I said, I reverted back to standard gravel instead of the fine stuff but it could also be because I used the mechanical vibrator and did not tap the concrete as often when I placed it in the PVC pipe.
Attachment 319216Attachment 319217
I know we come from the land down under but can us locals get a photo that we can relate to?
I am enjoying building the third and main pergola. I estimate that I have laid 100 cubic metres of concrete in my handyman life but this has been the ultimate in learning about this fantastic, malleable material. The mould I bought from America was stated to last 16 pours. I have made over 30 and have about 16 more to go so hope it lasts the distance.
Beside the practice/test pergolas I have made lots of tests columns and moulds.
There will be just under 9 ton of concrete in this pergola if I build the cross bars from concrete which I am seriously considering. I will then be able to curve the arches.
I have been very worried about lining up all the columns but am very pleased so far.
It is a great project both physically and mentally.
Mini-orb has been used form the columns.
I can't post the pictures properly. Sorry.
Hi rick_rine,
i spent 30 odd years making molds
statues column's retaining walls fountains pots
all out of concrete i used fibreglass to make the outer casting.
iv worked for BGC concrete in
perth for 12 months before getting sick of that.
ideally you want the thickest concrete possible
and use a plasticizer, this is an additive to make
your concrete go from 30 slump to 100 slump the additive last for about 15/20 min so you need to work fast
before the concrete returns to 30 slump or what ever it was before adding plasticizer, we used it all the time for tilt up walls were high strength was needed. The less water you add to concrete the less shrinkage you'll get.
Attachment 351882
The columns have been made with mini orb and look great. In the columns I used 10 mm reinforcmnt and a 4-1 gravel cement mix. In the beams I have used nylon fibres and two six mm reinforcment bars. It has been over two years in planning but looks amazing. Mostly mixed by hand. Poured in-situ. Almost perfectly straight and level surprise. I am using 4 concreting gravel, 3 bickies sand, and two cement for the crossbeams. They are 3 metres long with a span between the posts of two metres, they are .1 wide and 0.14 high. The supporting beams are 0.1 x 0.18. The posts are on a 0.3 x 0.3 base with 0.15 diameter columns moulded with mini orb. No scaffolding was needed as they sat up right and I poured the concrete in with a garden pot.
Attachment 351883Attachment 351884Attachment 351885Attachment 351885
The he pergola is twelve metres long, two metres wide, has 18 columns and has taken six months about so far to build. I am thinking of a clematis or wisteria. I got the idea when I was in Italy a few years ago. One of a kind! No one else would have one of these in their backyard, and probably no one else would want one either 😃
Rick
Seeing those columns immediately made me think Appian Way and Aqueducts. It looks extremely impressive!
An amazing project.
Regards
Paul