Related Experiment Video
Updated: May 10, 2025
08:59
A Freeze-Thawing Method to Prepare Chitosan-Polyvinyl alcohol Hydrogels Without Crosslinking Agents and Diflunisal Release Studies
Published on: January 14, 2020
17.2K
Chitosan Shrinking Fibers for Curing-Initiated Stressing to Enhance Concrete Durability
Dryver Huston1, Mandar M Dewoolkar2, Diarmuid Gregory1
1Department of Mechanical Engineering, University of Vermont, Votey Hall, 33 Colchester Ave., Burlington, VT 05405, USA.
Materials (Basel, Switzerland)
|April 24, 2025
Summary
This study enhanced concrete durability using shrinking chitosan-based fibers. Active fibers significantly improved freeze-thaw and chloride resistance, offering a sustainable construction solution.
Area of Science:
- Materials Science
- Civil Engineering
- Sustainable Construction
Background:
- Concrete's widespread use presents environmental challenges and durability limitations.
- Chitosan-based fibers offer a potential solution for enhancing concrete performance.
Purpose of the Study:
- To improve concrete durability and resilience through the incorporation of shrinking chitosan-based fibers.
- To evaluate the effectiveness of active (shrinking during curing) versus passive (pre-shrunk) chitosan fibers.
Main Methods:
- Two types of chitosan fibers (active and passive) were incorporated into concrete at various weight percentages (wt%).
- Durability was assessed using freeze-thaw and chloride penetration tests.
- Comparative analysis was performed against non-reinforced concrete and concrete with passive fibers.
Main Results:
- Active fiber-reinforced concrete demonstrated over 200% greater freeze-thaw durability than passive fiber concrete.
- Chloride penetration rates were significantly reduced in concrete with active fibers.
- Saltwater exposure tests showed up to 59% higher resistance in active fiber concrete compared to passive fiber concrete.
Conclusions:
- Shrinking chitosan-based fibers, particularly active fibers, substantially enhance concrete durability against freeze-thaw cycles and chloride ingress.
- This innovation supports the development of more sustainable and resilient construction materials.
Related Concept Videos
01:27Shrinkage in Concrete
55
Shrinkage in concrete is primarily due to water loss from evaporation, hydration of cement, or carbonation, leading to a reduction in volume. The volumetric contraction results in volumetric strain in concrete. However, in practice, shrinkage is measured as linear strain, which is one-third of the volumetric strain.
When concrete is still in its plastic state, it can undergo a decrease in volume by about 1% of its absolute volume. This decrease is known as plastic shrinkage. It arises either...
When concrete is still in its plastic state, it can undergo a decrease in volume by about 1% of its absolute volume. This decrease is known as plastic shrinkage. It arises either...
55
01:30Superplasticizers
69
Superplasticizers are advanced admixtures that enhance the workability of concrete by lowering the water content without compromising the strength of the material. These substances are highly effective water reducers, improving concrete flow, making it easier to work with, and enabling concrete to reach inaccessible areas or densely reinforced sections without mechanical vibration. The key components in superplasticizers are either sulfonated melamine or naphthalene formaldehyde condensates,...
69
01:22Fiber Reinforced Concrete
60
Fiber-reinforced concrete significantly enhances the structural and nonstructural properties of traditional concrete by incorporating fibers like steel, glass, and polymers. These fibers, varying from natural ones such as sisal and cellulose to manufactured ones like polypropylene and Kevlar, are mixed into hydraulic cement with aggregates. Steel fibers, often preferred for their robustness, contribute to improved ductility, toughness, and post-cracking performance. The concrete is classified...
60
01:21Drying Shrinkage
53
When hardened concrete is exposed to air with a relative humidity of less than 100 percent, it begins to lose the free water within its capillaries. As this water evaporates, the water initially adsorbed onto the calcium silicate hydrates migrates towards these now empty spaces and eventually evaporates as well. Over time, as more water leaves, the volume of the concrete decreases, a phenomenon known as drying shrinkage.
A portion of this drying shrinkage can be reversed; if the concrete is...
A portion of this drying shrinkage can be reversed; if the concrete is...
53
01:20Curing of Concrete
81
The hydration of cement takes place within the water-filled capillary pores. However, environmental elements can disrupt this process by evaporating water from the concrete surfaces. Sealed concrete with a water-cement ratio below 0.5 experiences self-desiccation, leading to water loss. The water loss in concrete is mitigated by curing. This technique involves keeping the concrete saturated to maintain the necessary temperature and moisture conditions, to optimally fill the spaces in the cement...
81
01:17Accelerators
62
Accelerators in concrete serve as admixtures to speed up the hardening process, enabling the concrete to achieve early strength faster. Although accelerators do not necessarily impact the time it takes concrete to set, they reduce this time in practice. A common accelerator is calcium chloride, which is particularly useful for hastening early strength development in cold weather or for rapid repair jobs that require quick heat generation after mixing.
The effectiveness of calcium chloride can...
The effectiveness of calcium chloride can...
62