I wanted to investigate in how concrete would act when being restrained by a flexible material (a balloon). By adding several balloons together inside a rigid form, they would also take shape by each other and the external shape. Like a specific brick-system, where they only can be placed in one specific way but then be perfect.
In the first stage i investigated how to cast into balloons and how the result would be. By using a funnel and making a more liquid mix (I used the mix of the flexible formwork but added water), the concrete easily flew into the balloons. By adding an extra tension to the shapes, with the string, the shapes became more interesting!
Before casting into the balloons, the rubber had to be stretched out, to maximise the amount that fits into them. So I simply blew them up for a few minutes before casting. I then started to fill the external wooden frame with the concrete filled ballons. To some I added rubberbands, to others I did nothing, and a few of the balloons where also heart-shaped which by themselves created interesting shapes!
When the box was filled and dried, this was how they look, the tob being more 3dimentional and the bottom more restricted:
And when stripping them of the ballons and then returning them to the shape, this is how they looked (because a lot of water was added, it created a layer on top where only water and a little bit of sand and concrete gathered, and cracked):
Learning about the adaptive formwork technique we wanted to take the opportunity to cast something which would not have been possible to cast otherwise. We came to the idea of using tape in order to create a mold. We chose fruit as our shapes and by rolling tape around them we were able to create a mold which had the shape of the fruits.
In contrast to the rather ‘free’ creation of the fruit molds we also made a more strict geometrical shape out of paper.
The concrete is still drying but will soon be taken out of its molds. We are a bit worried that the slurry might not have passed through the aggregate, even though we made the recipie with one part cement and one part water. But we will see what happends.
To be continued!
The objective for assignment four was to cast in a flexible formwork. Casting in a flexible formwork can be done in different ways and we chose to explore how to cast according to the topics of ‘varying stretch’ and ‘impressions’.
For the pannels we used the semi-self compacting concrete recipe which was handed out with the asignment.
Cement: 0.330 kg
Sand (0-4 mm) 0.417 kg
L40 0.175 kg
VMA 0.00625 kg
Water: 0.148 kg
Master Gelenium 51 0.003125 kg
After making the blend we found that the mixture was a bit too dry and we added 60 g of extra water. Looking at the casts we made we can draw the conclusion that we might have needed some more water to make the cament more flexible and tereby avoiding it to crack the way it did but also to make the concrete fully reflect all the details from the impression of the materials.
The first picture shows the result of the experiment for ‘varying stretch’. In this experiment we used jersey fabric and string to create a variation in the cast.
This picture shows the result for the experiment for the ‘impressions’. For this cast we used plastic shot glases, set out in a pattern, and a stiffer type of fabric. Since the result is a bit ruff we would like to try the same method but with a smoother mix and a more stretchy fabric.
This is the result of the new cast, which we are very happy with!
We wanted to investigate how concrete would behave when pouring it onto a almost vertical surface. So we attached a plastic sheet in a curve-like shape towards the wall. After mixing the concrete, with double amount of water, we decided to add some colour. Because we fell so much in love with the intense blue colour, we decided to not mix it in but to sprinkle some on top and see what would happen to in in the pour.
The result was quite nice. On the slope the concrete got really thin and cracked quite easy, in the “pool” the pigmentation gathered and created nice patterns of colour.
Looking at the thicker piece, the “pool”, you can see the difference in structure depending on what it was casted against. The plastic film created an extremely soft surface compared to the top which was quite 3dimentional and where the most of the colour ended up.
The edges are very thin and also very fragile. To summarise, it became a study of colour and pigmentation in concrete, but also a basic demonstation on how the surface of the form effects the surface of the cast.
Assignment 2 calculations:
The first cast, where the sand was the variable, our cast was very nice, compact and grey because we only used cement and almost no sand.
The second cast, with water as variable, we had very little liquids in the mix. This resulted in a very dry “cake” that fell apart when taking it out of the form.
When it comes to the last three, with pigmentation, almost no colour change can be detected. When mixing the three we felt that we needed to add more water. They where too dry to put into the formwork. Unfortunately we just added random amounts, and also different in between the different casts. therefore there is a difference in colour and density between them.
How things change over time can be frightening but also fascinating! Statues and sculptures of limestone or other more sensitive materials is heavily affected by what we call Acid rain. As the rain falls on the material, it slowly starts to eat of parts, little by little, until you no longer can recognise the initial motive. The method of making something finished, straight or closed, to later remove chosen or random parts is a method used in many fields, art, architecture etc. Siri Derkert osed this way of working on her artwork in the subway station Östermalmstorg in Stockholm. So by first covering a dark part of the wall In white concrete, and later apply force to revel the underlying color and then create lines.
Lime stone statues effected by acid rain.
First image: Unknown
Second image: Rheims Cathedral, France
Siri Derkert working on her art, Stockholm
When pouring concrete into a form there are several things that can go wrong. Can these features be turned into an asset? Can they be controlled or steered in any way? Air or water bubbles is a common problem but can create a beautiful pattern. Although it is hard to control the placement and intensity of the bubbles. Another issue when casting large amount of concrete is the lines created in-between different pours, because the color do differ between different bags of cement and is affected by many other aspects which is hard to control and will therefore result in slight color differences. This can also be turned into an asset.
Airbubbles in light gray casts
Material: Unknown, probably plaster or cement
Made by: Fernando Mastrangelo
Material: Pigmented Cement
Process: Casting in layers
Cement Ceramic vessels
Made by: Studio Twocan
Material: Pigmented Cement
Process: Mould casting
Made by: Hotson Bakker Boniface Haden architects + urbanistes
Osoyoos, BC V0H, Canada
Material: Sand, Clay, Grave, Water, Cement
Process: Rammed Earth
Rammed earth wall at the NK’Mip Desert Heritage Centre in Osoyoos, BC