Carbon Block: Work In Progress

I have really felt that when it comes to the majority of man-made goods there is little to no environmental benefits across the board. My first thought goes to the air purifier across the room as it is cleaning the air and providing a more comfortable environment, however upon closer consideration it is made of almost entirely plastic. Much of the materials around us today consist of plastics or other synthetic and over processed materials which have the main purpose of preserving themselves. Meanwhile their construction is lousy and intended for only a few years of use at best. This made me want to look into creating a product that was made to benefit the environment starting from its materiality. I first heard about the material Biochar on a Ted Talk focused on carbon sequestration. The main focus of the video was that we need additional forms of carbon sequestration other than the natural processes of trees and ocean algae. The video talked about natural carbon sequestration methods like biochar and basalt which capture carbon while also benefiting the environment and processes around them and have relatively limited environmental concerns. I think this topic relates to circular economy and sustainable design because it focuses on circular materiality. I think specifically with the ideas of degrowth we have to become more intentional about the products we incorporate into our lives and inanimate objects may be seen as wasteful in the future so to rethink them in a more useful and beneficial manner will make them much more efficient and sustainable.

When first considering the impact of the object the natural first place to start was materiality. I wanted the object/material to be carbon neutral or better yet carbon negative in all aspects. I think the biological cycle of the cradle to cradle framework best represents my project as all the materials I used were for the purpose of being returned to soil or reused in Lime projects. In terms of economic degrowth this is still a consumer good however the lack of synthetic or forever materials reduces its environmental impact and makes the end of life process much easier. I would raise caution with the rebound effect as the materials do still come from the Earth and over consumption would result in environmental decay and habitat loss in regions like Arizona, and Norway for the olivine, as well as using non-waste biomass to fulfill biochar needs. I don't want this new material design to ramp up raw material extraction causing more harm than good.

Lime:  Lime comes from limestone (CaCO3) where it is heated at 900-1000℃ in the process called calcination to remove the CO2 leaving you with quicklime (CaO). The process of calcination is an extremely energy intensive process that in addition puts CO2 into the atmosphere. After the lime is calcined it is then slaked which is the process of adding water (H20) to create (Ca(OH)2). In this process significant heat is released which could be harnessed and used to make the calcination process less energy intensive. Slaked Lime orf Hydrated Lime can then be mixed with aggregates and pozzolanic materials to form a Lime Concrete. The process of the lime solidifying involves the lime re-absorbing CO2 from the air going from (Ca(OH)2 + CO2) to (CaCO3 + H2O) or Calcium Carbonate (Limestone) and Water. The material of lime is energy intensive but circular due to the ability to recalcine cured lime and restart the process. Technological advancements have also allowed for greener forms of Lime. Algae based lime double dips on the carbon absorption through the algaes photosynthesis absorbing CO2, calcination releasing the CO2, and curing process which recaptures the released CO2 which offers us carbon negative options for lime building materials. 

Pumice: Pumice is a lightweight volcanic rock that has pozzolanic properties which means it reacts with calcium hydroxide (Ca(OH)2) and forms a cementitious material. I chose to use pumice due to its lightweight properties and availability however any pozzolanic material will work. 

Biochar: Biochar is organic waste heated in low oxygen environments at high temperatures to create a material that is stable and rich in carbon in a process called pyrolysis. Although the process of pyrolysis is energy intensive and releases pollutants into the air, modern pyrolysis systems have capture systems which can byproducts like heat, oil, and gases reuse them to power the pyrolysis process, heat local water systems, etc. The main use of biochar in the material composition is as an aggregate in place of commonly used sand. This increased the porosity and decreased the weight and density of the composition, making it ideal for non-structural applications.

Olivine/Peridot: For the incorporation of crushed olivine I lined the mold with first vaseline to allow for easy mold removal, but it also allowed the olivine rocks to stick to the sides of the mold. I chose not to incorporate the olivine into the mixture as it greatly increased the weight of the material and I wanted the green rock to be visible as it goes through the process of carbon weathering. The visible changes of olivine start with a dulling of its hues, become more milky or chalky due to a breakdown of the crystalline structure, then begin to turn to a shade of brown, yellow, or gray. The olivine rock dissolves leaving Magnesite, Silica, Magnesium Hydroxide, Serpentine, Iron Oxides, and Clay materials which can all be used to improve soil quality in the right application. Olivine is the most abundant material in Earth's upper mantle which means it does not take extensive energy to reach deep into the earth's surface. However there are questions of deforestation and habitat loss from extraction processes. 

Limitations and expansions: The primary limitations for this project was time and material availability. Because I am working with materials primarily used for construction and wholesale purposes, getting my hands on the proper or most effective materials was a struggle. For starters I would want to work with algae based lime as it double dips on the carbon sequestration making it a greener material. I would also like to incorporate metakaolin clay, fly ash, or other stronger pozzolanic materials however they often were accompanied by large order minimums, long shipping times, or high shipping costs. Finally, I wanted to use fine olivine sand as a carbon sequestering pigment integrated throughout the entire composition. The smaller grain size would allow for increased chemical weathering while also serving as a lighter weight alternative to the crushed olivine. In terms of time as a limitation for this project, it takes lime mortars about 90 days to fully cure and harden which I would want to test for multiple different compositions to test physical properties. I also wanted to test the carbon sequestration as this is a conceptual material, I have to test it to identify if it works as intended. I also wanted to test the chemical weathering in different environments. Although it takes years to weather in nature I wanted to test some environments such as a kitchen or bathroom to allow for higher levels of humidity, but also some more controlled environments such as a greenhouse cabinet, or next to an open window. Overall, I think having more time for this project would have allowed me to dive deeper into different material compositions and try out new materials, however I have really enjoyed this project and want to continue testing out carbon sequestering materials in the future.