**How Oyster Shells Are Inspiring a Revolution in Cement Durability**
While the modern world is built with cement, its production is one of the largest sources of greenhouse gas emissions. Because of this environmental impact, enhancing cement’s durability and safety is more important than ever.
In a groundbreaking study from Princeton University, scientists have found design inspiration in an unlikely place: the humble oyster and its iridescent composite material, nacre.
—
### Nature’s Masterpiece: Nacre
Nacre, also known as “mother of pearl,” lines the inner shell of oysters and other saltwater bivalve mollusks. It’s well-known for its shimmering beauty and is frequently used in jewelry. But beyond its aesthetic appeal, nacre is an architectural marvel.
At the microscopic level, nacre consists of hexagonal “tablets” made of aragonite—a common natural form of calcium carbonate. These tablets are held together by a soft biopolymer, acting like an organic glue. This unique combination gives nacre impressive strength, flexibility, and crack resistance.
—
### Bio-Inspired Engineering
Scientists at Princeton University’s Department of Civil and Environmental Engineering wondered if this natural design, shaped by half a billion years of evolution, could be applied to human building materials like cement.
Their research, published in the journal *Advanced Functional Materials*, aimed to replicate the microscopic characteristics of nacre to improve cement toughness.
“This synergy between the hard and soft components is crucial to nacre’s remarkable mechanical properties,” said Shashank Gupta, a graduate student and co-author of the study. “If we can engineer concrete to resist crack propagation, we can make it tougher, safer, and more durable.”
—
### The Experiment: Mimicking Nacre’s Structure
Gupta’s team created three types of multi-layered beams from alternating cement paste sheets and thin polymer layers:
1. A simple stack of cement and polymer layers.
2. A beam featuring hexagonal grooves etched into the cement.
3. A beam with the cement fully cut into hexagonal-shaped plates or “tablets,” mimicking nacre’s microscopic structure.
All three were compared to a traditional solid cement beam with no polymer or hexagonal features.
—
### Remarkable Results
The reference beam without modifications showed typical brittleness and no ductility. In contrast, all three bio-inspired beams displayed significantly increased toughness and ductility.
Most impressively, the beam mimicking nacre’s hexagonal tablets exhibited:
– 17 times greater toughness
– 19 times more ductility
compared to the standard cement beam, all while maintaining equal strength.
—
### Engineering Stronger Materials by Design
“Our bio-inspired approach is not simply to mimic nature’s microstructure, but to learn from the underlying principles and use that knowledge to engineer human-made materials,” explained Reza Moini, co-author of the study.
He added, “One of the key mechanisms that makes a nacreous shell tough is the sliding of the tablets at the nanometer level. In other words, we intentionally engineer defects in brittle materials as a way to make them stronger by design.”
—
### Looking Ahead
This innovative research opens exciting pathways to create safer, tougher, and more durable building materials with inspiration from nature’s own ingenious designs. By harnessing such biomimicry, the construction industry can potentially reduce its environmental footprint while improving structural resilience.
Once again, mother nature provides.
https://www.popularmechanics.com/science/animals/a69093939/engineers-discover-durable-cement-secret-stronger/