A new structural material builds upon the promise of enzyme-enhanced CO2 mineralization to overcome decarbonization challenges in the construction industry. Researchers from Worcester Polytechnic Institute (WPI; Worcester, Mass.; www.wpi.edu), led by Nima Rahbar, head of WPI’s Department of Civil, Environmental and Architectural Engineering, developed the new enzymatic structural material (ESM) using a novel capillary-suspension process that incorporates CaCO3 crystals into a sand and carbon matrix (hydrochar). The ESM’s crystals are created from sequestered CO2 using integrated enzyme (carbonic anhydrase) conversion, meaning that the material can be classified as “carbon negative.”
Source: WPI
The team found that the ESM demonstrated many properties comparable to or exceeding conventional concrete, such as minimum compressive strength and water durability, while requiring much milder processing steps. Whereas conventional concrete requires around 28 days for curing at high temperatures, ESM can cure in just hours at much lower temperatures. The material is also readily repairable and recyclable and exhibits a degree of self-healing capability, say the researchers.
Some previous efforts to incorporate bio-based materials into low-carbon construction materials have struggled with water durability and strength. WPI’s ESM overcomes these issues via its capillary suspension process, which actually forms its own “hydrophobic carbon-backbone microstructure” under thermal curing that helps to optimize porosity and stabilize the CaCO3 minerals.
According to Rahbar: “Producing a single cubic meter of ESM sequesters more than 6 kg of CO2, compared to the 330 kg emitted by conventional concrete.” Details of this study were published in a recent issue of the journal Matter.