The aim was to create a fine concrete texture, looking like skin.
First the fine aggregate was poured into a frame. A layer of crinkled paper was put on top, and then the cast was filled with the coarse aggregate and filled up with the mix of cement and water.
unfortunately the concrete didn´t went all through the aggregate, so only parts of it came out with the skin-texture.
Probabely the mix was not liquid enough, or not shaked enough so it could reach the bottom of the course aggregate.
What we want to do is to create a kind of shell which with very free form by pouring the concrete onto sandpile. After a test——concrete with different consistencies pouring onto the same sandpile and evaluating the performances, we are looking forward to finding the most suitable consistency for a concrete shell.
Firstly we made a test showing what can 10 gram water do in a default mix, we added 10 more gram water each consistency and poured them onto a slanted panel. They performed wide differences which totally beyond our imagination.
Then we began to deal with the main question. We made four different consistency (the diagram shows the exact figure) and poured them onto the sandpile, trying to made them flew freely and tolerating the overlapping part for better evaluation.
From the experiment on how concrete flow with different consistencies, we learned that viscosity did have great affect on how it shaped. And the amount of water decided concrete’s viscosity. Concrete of mixture 1 and mixture 2 flew quickly and hard to shape, after decreasing the water, it became easier to shape the shell. Therefore, for further development, concrete between mixture 3 and mixture 4 can be used to shape a shell, with appropriate flowability to extend and enough viscosity.
I did a test with the technic “prepacked aggregate concrete“.
First I build a little box which I divided in 25 parts with paper walls. I filled the little “rooms” as in the diagram below. When every “room” was filled with either sand or aggregate I carefully took out the paper walls and poured in the slurry. (1kg cement, 1,2 kg water). I hope the “slurry” will come down through the aggregate.
The result wasn’t so good. I think it depends on the fluidity of the slurry.
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.