Our bespoke package of mechanical testing and materials characterisation helped Cellment evaluate the properties of a new bio-composite material, consisting of particulate (sand) and a gel matrix (binder).
Samples of Cellment’s composite material supplied for compression testing
The challenge: answering questions about material properties
Cellment is developing a composite material that combines sand with a bio-based binder for potential applications in the built environment.
They commissioned nC2 to test three versions of the material with different binder-to-sand content ratios and manufacturing methods, to answer the following questions:
- Which formulation offered the best strength and flexibility?
- How did manufacturing influence quality and reliability?
They also wanted to gain insights into the visible defects and inconsistencies in the material.
Applying nC2’s expertise: mechanical testing and materials characterisation
We designed and delivered a structured programme of mechanical testing and materials characterisation.
A sample ready for testing in the Instron 5569
Mechanical testing – measuring material performance
Our experts carried out compression testing (performance under load) and bending testing (resistance to failure).
Findings
Formulation C (which had the lowest binder content):
- Achieved the highest strength in both compression and bending.
- Showed greater flexibility before failure.
- Also showed greater variability, indicating inconsistency in manufacture.
Formulations A and B:
- Delivered lower strength overall.
- Showed slightly more consistent behaviour in some cases.
Key insight
- Performance was influenced not just by material composition, but by how the material was manufactured. As it was unclear which variable had more influence, further testing to investigate this was recommended.
Materials characterisation – understanding sample composition
The team carried out mass measurement and visual inspections for consistency, and microscopy to understand the materials’ internal structure.
A sample at x50 magnification (A), x100 magnification (B) and x200 magnification (C)
Findings
There was significant variation in sample quality:
- Surface defects (air pockets, uneven geometry) were common.
- Formulation C showed fewer visible defects, but still high variability.
All the formulations shared a similar internal structure:
- Particulate material (sand) bonded in a gel matrix (binder).
- Differences linked to binder content and manufacturing method.
Mass measurements proved useful:
- A simple way to monitor consistency.
- They correlated with mechanical performance variation.
Key insights
- Manufacturing consistency is critical to achieving reliable material performance.
- Simple quality checks (such as mass measurement) can act as effective indicators of consistency.
nC2’s added value
With a range of expertise, experience and lab facilities across materials science techniques, our experts could:
- Design a tailored testing package for Cellment, combining the most suitable methods to gain the required insights.
- Refine the approach to data collection and evaluation in the absence of recognised standards for this novel material.
- Prepare samples to the specific geometries needed for robust test results.
- Provide expert opinion based on the results, including recommendations for future testing.
The outcome: evidence and advice enabling Cellment to move forward
Our results empowered Cellment to advance their material development through:
- Clear identification of the best-performing formulation for structural performance.
- Improved understanding of how the material structure and processing affects performance.
- Identification of key areas for improving product consistency.
- Recommendations to focus their R&D going forward.
