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Common adhesives for nonstructural applications are manufactured using petrochemicals and synthetic solvents. These adhesives are associated with environmental and health concerns because of their release of volatile organic compounds (VOCs). Biopolymer adhesives are an attractive alternative because of lower VOC emissions, but their strength is often insufficient. Existing mineral fillers can improve the strength of biopolymer adhesives but require the use of crosslinkers that lower process sustainability. This work introduces a novel approach to strengthen biopolymer adhesives through calcium carbonate biomineralization, which avoids the need for crosslinkers. Biomineral fillers produced by either microbially or enzymatically induced calcium carbonate precipitation (MICP and EICP, respectively) were precipitated within guar gum and soy protein biopolymers. Both, MICP and EICP, increased the strength of the biopolymer adhesives. The strength was further improved by optimizing the concentrations of bacteria, urease enzyme, and calcium. The highest strengths achieved were on par with current commercially available nonstructural adhesives. This study demonstrates the feasibility of using calcium carbonate biomineralization to improve the properties of biopolymer adhesives, which increases their potential viability as more sustainable adhesives.
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This content will become publicly available on September 9, 2026
Cross-linking biopolymers using salt for frost susceptible silty soils
Advancements in engineering construction have led to an increase in significant challenges with foundations and pavement infrastructure built on silty soil. Silty soils are created through the combination of mainly silt-sized particles (< 0.075 mm), typically with a small percentage of clay, and are vulnerable to frost. Biopolymers can possibly be an alternate solution for calcium-based stabilizers or be used as a co-additive. This study aimed to investigate the interaction of biopolymer-induced soil with multivalent ions via unconfined compressive strength to identify a potential stabilizer and appropriate dosages. For comparative analysis, biopolymers with different cations on silty soil strength were evaluated after curing for 7 days and 28 days. The results indicated that the biopolymer networks develop slowly; however, cross-linking the biopolymers with different cations enhanced their rate of stiffness and strength increase. This composite sample indicated a possible solution for partially replacing calcium-based stabilizers in frost-susceptible silty soil.
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- Award ID(s):
- 2327384
- PAR ID:
- 10663099
- Publisher / Repository:
- CRC Press
- Date Published:
- Page Range / eLocation ID:
- 280 to 285
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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