From 200 Possible Concrete Mixes to 30 Candidates: Optimising your R&D Plan.
Concrete product development can become deceptively busy.
Change the binder ratio. Make a mix.
Adjust the water content. Make another...
Change the aggregate grading or particle packing. Make another...
One result improves while another moves in the wrong direction. Strength increases, but workability falls. A further adjustment is made, followed by another round of mixing and testing.
Before long, the development team has produced dozens of mixes and a substantial dataset, but it may still be unclear which material characteristics and formulation variables are actually controlling performance.
More experiments have been completed, but the project may not be much closer to a reliable commercial product.
On a recent commercial concrete product-development project, Reformix approached this problem differently. Rather than starting with an extensive series of mix trials, we first focused on understanding the constituent materials and using that evidence to structure the experimental program.
Why more mix trials do not always create more understanding
Trial mixes are an essential part of concrete and cementitious-materials development. The problem is not experimentation itself. The problem arises when successive experiments change several interacting variables without a clearly defined question.
Concrete performance is influenced by a complex combination of factors, including:
binder composition and reactivity
water demand
particle-size distribution and packing
aggregate characteristics
admixture compatibility
mixing sequence
curing conditions
material variability
Changing one component can affect several properties at once. An increase in strength may result from improved reaction, reduced water content, better particle packing or some combination of these effects. A decrease in workability may have a similarly complicated cause.
If the experimental program is not structured to distinguish between these effects, each additional result can add data without adding much understanding.
This often creates a familiar R&D cycle: change a variable, observe the result and then change another variable based primarily on experience or intuition. Experienced judgement remains valuable, but it becomes much more powerful when it is supported by material evidence and testable hypotheses.
Our advice: Start by understanding the materials
Before going deeply into mix design, Reformix characterised the materials that would form the basis of the product.
The investigation considered their mineralogy, chemistry, particle-size distribution and packing, morphology, and microstructure. Each of these characteristics can influence how a material behaves within a concrete or binder system.
Mineralogy helps identify the crystalline and amorphous phases present and provides information about potential reactivity.
Chemical composition helps establish what is present in the material and whether particular components may support or constrain the intended application.
Particle-size distribution and packing affect water demand, workability, density and the way particles occupy the available space within the mix.
Morphology and microstructure provide further information about particle shape, surface characteristics and the physical structure of the material.
The purpose was not to predict a finished concrete formulation from analytical data alone. Materials characterisation cannot replace mix trials or performance testing.
Its value was in identifying which characteristics were most likely to influence performance and using that information to decide what the experimental program needed to test.
Turn observations into testable hypotheses
Once the materials were better understood, the project team could move from broad trial and error to a series of more focused questions.
Was a particular performance limitation more likely to be related to binder reactivity, particle packing, water demand or another material characteristic?
Which variables needed to be isolated?
Which combinations were unlikely to provide useful results?
What result would justify progressing a formulation, modifying it or removing it from the program?
These questions allowed the planned experimental program to be reconsidered. Instead of treating every technically possible formulation as equally valuable, the team could prioritise the combinations most likely to answer a defined question or meet the project’s commercial requirements. Each experiment still involved uncertainty. That is inherent to R&D. The difference was that each mix had a clear purpose and an intended decision attached to its result.
Narrow the formulation space deliberately
The initial formulation space contained roughly 200 possible mixes...
Testing every possibility would have consumed a significant amount of material, laboratory time and project budget. It would also have generated a large volume of results requiring interpretation. Using the characterisation findings and the hypotheses developed from them, the team progressively narrowed that space to about 30 candidate formulations for further validation.
The specimens shown in the accompanying photograph form part of that shortlisted program. There are still many specimens because credible development requires replication, comparison and testing across relevant ages and conditions.
The important distinction is that the shortlist was not arbitrary. Each candidate was selected to test a particular formulation concept, material interaction or performance question.
The process did not eliminate experimentation. It concentrated the experimentation
where it was most likely to improve the next decision.
A successful laboratory mix is not yet a commercial product
Narrowing the formulation space is an important step, but it is not the end of product development. Candidate mixes still need to be assessed against the requirements of the intended application. Depending on the product, this may include:
fresh properties and practical workability
strength development
durability and exposure requirements
repeatability across material batches
sensitivity to moisture and normal production variability
mixing, batching and curing requirements
raw-material availability and quality control
production cost and commercial feasibility
performance at pilot or production scale
A mix that performs well under controlled laboratory conditions will not necessarily behave identically when production volume, equipment, moisture conditions and material variability change.
This is why commercial product development requires more than finding the strongest laboratory result. The objective is to develop a formulation and production process that can deliver the required performance reliably under realistic operating conditions.
The commercial value of structured materials R&D
A structured R&D program does not guarantee that every hypothesis will be correct. It does, however, make the result of each experiment more useful. A negative result can still create value if it eliminates an unsuitable pathway or reveals which assumption needs to change. A positive result is more valuable when the team understands why it occurred and what must remain controlled for it to be repeated.
This approach can help a development team:
reduce unnecessary formulation trials
make better use of laboratory materials and testing resources
separate correlation from likely cause
identify risks earlier in the program
create clearer progression and stopping criteria
focus validation on the most credible candidates
build a stronger technical basis for scale-up and commercial decisions
In commercial product development, the difference between a sequence of mixes and a structured experimental program can represent months of work and a substantial amount of money...
Materials development will always involve iteration. The objective is not to remove trial and error completely. It is to ensure that each trial answers a useful question and improves the decision that follows.
Support for concrete and materials product development
Our work can include materials characterisation, formulation and mix design (Low-Carbon or more conventional), experimental-program development, process optimisation, pilot-scale validation and commercialisation support.
If your R&D program is producing more mixes than decisions, we can help determine what the materials are telling you and structure the development program around the technical and commercial questions that matter.
Contact Reformix to discuss your material, formulation challenge or product-development program.
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