Interfacial Transition Zone
Interfacial Transition Zone - Related Videos
08:59
Determination of Aggregate Surface Morphology at the Interfacial Transition Zone (ITZ)
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Cited by 9 •
2019
Hereby, we proposed a protocol to illustrate the effect of aggregate surface morphology on the ITZ microstructure. The SEM-BSE image were quantitatively analyzed to obtain ITZ's porosity gradient via digital image processing and a K-means clustering algorithm was further employed to establish a relationship between porosity gradient and surface roughness.
01:28
Transition Zone
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2024
The transition zone in concrete is a critical area where aggregate meets cement paste, marked by a distinct porosity and weakness compared to the surrounding material. The adhesion around the aggregates is primarily due to Van Der Waals forces. The voids within this zone influence its robustness; initially, it is less durable than the surrounding bulk mortar due to larger voids. Initially, when concrete is compacted, a higher water-cement ratio near the aggregates leads to the formation of...
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
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2017
Here, we present a protocol to trigger an orientational transition of a liquid crystal in response to temperature. Methodologies are described for preparing a sample in order to observe the transition and the detailed transitional evolution.
02:31
Phase Transitions
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2020
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...
01:58
Cooperative Allosteric Transitions
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2020
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
FAQs
Near an aggregate surface, particle packing is less efficient and the wall effect alters how cement particles arrange. Bleeding can concentrate water locally, while hydration creates larger products in this region than in the bulk paste. These combined effects produce a more porous ITZ, making it a structurally distinct part of the concrete rather than a simple geometric boundary.
The ITZ can act as a preferred route for damage and transport because its porosity and susceptibility to microcracking are greater than those of the surrounding matrix. Once cracks or transport paths develop, they can influence how fluids move through concrete. This helps explain why a relatively thin region can affect bulk strength, stiffness, permeability, and durability.
Aggregate characteristics, water-to-cement ratio, curing, and supplementary cementitious materials are the main engineering variables identified for improving ITZ structure. Their effects matter because the zone forms under local conditions that differ from the bulk matrix. Adjusting these variables targets not only the paste overall, but also the ITZ-related weaknesses that influence composite performance.
Compared with bulk cement paste, the region beside coarse aggregate may contain larger hydration products, higher porosity, and greater vulnerability to microcracking. This contrast matters because concrete behaves as a composite whose aggregate and paste interact through this locally weaker area. Evaluating only the bulk matrix can therefore miss mechanisms that govern transport and mechanical performance.
An ITZ-focused improvement strategy can consider aggregate characteristics, water-to-cement ratio, curing conditions, and supplementary cementitious materials. These interventions target particle packing, bleeding, hydration, and local porosity near aggregate surfaces. The intended outcome is a better-structured transition zone and, consequently, improved strength, stiffness, permeability, or durability of the concrete.
Engineers pay particular attention to the ITZ when a concrete design must balance mechanical performance with resistance to fluid movement and deterioration. The zone is relevant to strength and stiffness because microcracks can weaken composite behavior, and to durability because transport through porous or cracked regions affects permeability. Its condition links local structure to whole-material performance.