Related Experiment Video
Updated: Aug 5, 2025
05:38
Production and Analysis of Sporosarcina pasteurii Biocement Bricks Using Custom 3D-Printed Molds for Unconfined Compression Tests
Published on: March 7, 2025
392
Performance Modeling of Spherical Capsules during Mixing of Self-Consolidating Concrete
Samir E Chidiac1, Mouna A Reda1
1Department of Civil Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L7, Canada.
Materials (Basel, Switzerland)
|March 29, 2023
Summary
Capsule survival in self-healing concrete is crucial. This study found that capsule radius-to-thickness ratio, concrete properties, and mixing speed significantly impact survival during concrete mixing.
Area of Science:
- Materials Science
- Civil Engineering
- Concrete Technology
Background:
- Autonomous healing in concrete systems relies on embedded capsules.
- Capsules must survive concrete mixing but rupture upon cracking.
- Standardized testing for capsule survival during mixing is lacking.
Purpose of the Study:
- To investigate factors influencing capsule survival during concrete mixing.
- To correlate capsule shell properties and concrete rheology with survival rates.
- To develop a predictive model for capsule survivability.
Main Methods:
- Utilized finite element modeling to simulate capsule performance.
- Employed statistical modeling to predict capsule survival rates.
- Analyzed correlations between capsule properties, concrete rheology, and external forces.
Main Results:
- Capsule survivability is significantly influenced by radius-to-thickness ratio (30-45 recommended).
- Concrete rheological properties, average paste thickness (APT), aggregate characteristics, and mixer speed are key factors.
- Predictive model achieved 68% confidence in survival rate estimation.
Conclusions:
- Optimizing capsule design and understanding concrete mix properties are essential for successful autonomous healing.
- The study provides insights into critical parameters for capsule survivability in self-healing concrete.
- Recommendations are provided for capsule radius-to-thickness ratios to ensure both survival and functionality.
Related Concept Videos
01:14Design Example: Managing Concrete Workability
106
This example deals with managing the workability of concrete for a raft foundation project under hot weather conditions. Workability is crucial for ensuring the concrete is easy to place, compact, and finish. In this scenario, a slump test — a common method to measure the workability of fresh concrete — initially indicated low workability. This was attributed to the rapid water loss from the concrete mix, exacerbated by the high temperatures causing the course aggregates to heat up.
106
01:23Behavior of Concrete Under Compressive Load
231
Concrete exhibits specific behaviors under different compressive loads. Understanding this is crucial for understanding its structural integrity. When concrete undergoes uniaxial compression, it tends to develop cracks that run parallel to the direction of the force. These parallel cracks stem from localized tensile stresses that occur perpendicular to the compression direction. Additionally, angled cracks may appear due to the formation of shear planes.
As the concrete specimen fractures under...
As the concrete specimen fractures under...
231
01:16Dynamic Modulus of Elasticity of Concrete
443
The dynamic modulus of elasticity assesses how a concrete structure deforms under impact or dynamic loads. It is typically higher than the static modulus of elasticity, measured under slow, steady loading conditions.
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by...
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by...
443
01:20Elasticity in Concrete
121
Upon subjecting concrete to moderate or high uniaxial compressive or tensile stresses, the strain response is non-linear relative to the stress applied. As the stress is removed, the resulting stress-strain curve deviates from the original path traced during loading, creating a hysteresis loop, indicative of the concrete's non-linear and non-elastic properties. Typically, a material's modulus of elasticity, which is a measure of the material's stiffness, is inferred from the linear...
121
01:30Mixing Concrete
145
Concrete mixing ensures a homogenous blend where aggregates are well-coated with cement paste. Concrete mixing is typically done using two main types of mixers: batch and continuous. Batch mixers handle one batch at a time, thoroughly combining materials before discharging and receiving the next batch. In contrast, continuous mixers receive a steady flow of ingredients, mixing them consistently and discharging without interruption. Within batch mixers, tilting drum mixers mix with internal...
145
01:13Pumped Concrete
105
Concrete in large quantities can be pumped across long distances for placing in inaccessible sites. This system comprises a hopper that receives concrete from a mixer, a pump to propel the concrete, and pipelines that facilitate its delivery.
For direct-acting pumps, the concrete enters the pump via the inlet valve under the action of gravity and suction created by the movement of the piston. This concrete is then forced into the pipeline and out through the outlet valve by the forward movement...
For direct-acting pumps, the concrete enters the pump via the inlet valve under the action of gravity and suction created by the movement of the piston. This concrete is then forced into the pipeline and out through the outlet valve by the forward movement...
105