Cómo hacer ecoladrillos caseros/en
This page explains how to make homemade bricks from a mixture of cement and plastic.
I started this project to recycle my plastic waste myself. Even though I'm trying to reduce my plastic consumption, there's always some left over. With this technique, I can turn that little bit into bricks, and when I have a lot of them, I'll make something useful out of them.
Making bricks is an excellent solution to the problem of excess plastic because, unlike other forms of recycling, it allows for the recycling of huge amounts of plastic, of any type, without laborious prior sorting and without it becoming waste again for decades, even centuries.
Materials
Cut plastic
I mainly use semi-rigid plastic (bottles, trays, etc.) cut by hand with scissors. I tried using a blender, but it didn't work. Perhaps a food processor would work, but I didn't try. At first, I also cut grocery bags, but if the scissors aren't sharp enough, they're very laborious and add very little volume, so I stopped. Additionally, grocery bags (in Buenos Aires at least) can be placed in so-called "love bottles," which are then recycled to produce plastic lumber, a solution in many ways very similar to eco-bricks.
Brick molds
I made my own molds with some old wood and nails.
Concrete
That is, the classic mixture of cement, sand, and water, for which you also need a bucket and a shovel or something similar to mix.
Procedure
Mix three parts sand, one part cement, and one part water in a bucket. Stir until the desired consistency is achieved.
The amount of concrete you need to prepare will depend on the number of bricks you want to produce and the amount of plastic you want to recycle. For example, 1,500 ml of sand, 500 ml of cement, and 500 ml of water (plus the plastic) produce three bricks.
It's important to prepare the concrete before adding the plastic, otherwise mixing everything becomes much more laborious. You can mix it with a garden shovel or trowel. In the video, I do it by hand, but someone later mentioned that cement can be toxic, so I recommend wearing gloves, especially if you're making a lot of bricks or in a row.
Add two parts plastic to every part cement. Continuing with the previous example, 1,000 ml of plastic would be required to add 1,500 ml of sand, 500 ml of cement, and 500 ml of water.
The exact ratio of plastic is delicate. Too much plastic produces ugly, brittle bricks, while too little is inefficient, as the point is to recycle as much plastic as possible. After several tests, I concluded that roughly two parts plastic to one part cement works well. However, the amount of plastic that goes into the measuring cup we use depends on the pressure we apply. Ideally, we would weigh the plastic to get an exact ratio, but I haven't done that experiment yet.
Transfer the mixture to the mold and press down firmly to fill the molds as much as possible. Again, using your hand is much easier. I recommend wearing gloves.
It is important to let it dry in the shade , as leaving it in the sun can cause the bricks to crack.
Adobe version
The steps above are the result of several tests and failed attempts. In this section, I describe some of these tests and the lessons learned.
CONICET Bricks
For this project, I was inspired by research conducted by CONICET (Argentina's National Scientific and Technical Research Council), which produced much more sophisticated ecobricks. The CONICET bricks have several advantages:
- Each one is made up of 20-30 recycled plastic bottles, crushed and mixed with cement, which thus remain out of the ecosystem for decades, if not centuries.
- They meet all the technical and legal requirements for use in buildings up to two stories high in Argentina.
- They provide twice the thermal insulation of conventional bricks, so some projects can use half the number of bricks, thus reducing costs.
- They are almost 40% lighter than conventional bricks, so you can also save on foundations.
- Their production does not require laborious and expensive waste separation (the bottle, cap, and label are all crushed together) or specialized labor, making them a potential source of employment and mass recycling.
CONICET released the details of the research so that municipalities and entrepreneurs could replicate the technique and commercialize it. Thus, by 2017, the municipality of Junín de Mendoza was already recycling more than 60% of its plastic using this technique (probably more today). Another adopter in Córdoba is using it to build social housing and even won a Google Innovation Award .
However, when I tried to download the research to adapt it to my own purposes, it was no longer available. I wrote to them, but they didn't respond, so I had to start from scratch.
See also
- LCA of cement - Life cycle and environmental impact of cement