SANDY CURTH
about
class site
Functionally Graded 3D printed earth
Soil is full of materials with varying structural and insulative
properties. Why not create an additive assembly system
to recombine the soil of a given site into a material with
designable performance traits? Can we take air and bacteria
and create printed structures that are both lightweight and
slowly increasing in strength over time?
Aeration
Foamed concrete has been in use since the 1920's for
pre-fab buildings, cold resistant structural performance,
and various other niche applications. The key challenge of
an aerated material is the loss of compressive strength.
We propose an additive deposition process in which
cementitious or earthen material is selectively aerated to
vary insulative and structural performance as needed across
a design.
MICP
Microbial-Induced Calcite Precipitation (MICP) uses naturally
occurring bacteria to bind soil particles together through
calcium carbonate (CaCO3) crystals. We are considering this
approach as a way to create locally sources sustainable
earthen building material that strengthens over the course of
weeks or months as the bacteria builds up calcium in the gaps
between aggregate. The bacteria most commonly used is
Sporosarcina Pasteurri (S.Pasteurri). To activate the process the
bacteria are combined with a cementation solution of Urea and
Calcium. Urea is a crystalline compound that is the main
nitrogenous breakdown product of protein metabolisms. The
process of MICP through bacteria, urea, and calcium ions is
known as microbial urea hydrolysis.
Team
Laura Maria Gonzalez, Sandy Curth
References
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