Behind the scenes in the lab at wienerberger: Dr. Aldo F. Gallardo shares scientific insights on concrete roof tiles

Dr. Aldo Fernando Sosa Gallardo, Concrete Technologist at wienerberger UK, shares his experience working at wienerberger laboratory in Kingsbury. He describes his daily routine at the lab and the scientific research, experimental practices, and processes involved in the production of concrete roof tiles.

“To create a concrete roof tile, we combine several ingredients and the two most important are cement and sand. Cement is one of the most complex inorganic materials in the world, and the second most used material globally. Cement contains various clinker phases with complex chemical compositions and when water is added to it, numerous simultaneous reactions begin. These reactions release different ions and create a pore solution that, over time, transforms and forms hydrated products. These products are what determines the strength, durability, and overall performance of concrete.”

“On the other hand, sand makes up roughly 70% of the tile’s composition. It is essential to understand sand’s chemical and physical properties, such as density, water absorption, particle size distribution, texture, and shape, because the characteristics of each component influence the final behaviour and performance of the material. In the lab, we evaluate all these characteristics to determine whether a sand source is suitable.”

Dr. Aldo Gallardo holds a master’s degree in Advanced Solid-state Chemistry and a PhD in Material Science, focusing on cement hydration and electrochemical impedance spectroscopy (EIS), a technique used to measure how a material or system responds to an electrical signal across a range of frequencies. He joined wienerberger in 2024 and since then has been working closely with the technical, production, research and development teams to develop new products, improve mix designs, material formulations, and optimise processes to enhance the properties and performance of our concrete roof tiles.  

“I recently led the experimentation, raw material characterisation, and mix design for our new concrete roof tile factory in Smeed Dean.  This experiment was a collaborative effort where we studied multiple sand and cement sources, evaluating their morphology, grading, absorption, texture, and performance. Using modelling techniques and the design of experiments, we created blends that delivered better performance. Once the lab results were validated, we scaled the process to production and finetuned it to deliver a more optimised final mix design within a short timeframe. Today, the final product of that experiment is one of our strongest and fastest selling tiles, receiving excellent feedback from both customers and internal teams. Overseeing this project is one of my proudest achievements at wienerberger.” 

As a concrete technologist at wienerberger, Dr. Aldo Gallardo’s role includes research, designing experimental plans, analysing materials, preparing mixes, and planning tests and production trials. He also trains colleagues within the concrete division, prepares concrete courses for the technical team, analyses results, compares performance, and presents scientific conclusions to the wider team so informed decisions can be made. 

“One of the most rewarding aspects of my job is taking research from the laboratory and successfully applying it on the production line. When evaluating new materials, the number of tests required depends on how much existing data we have and the level of statistical confidence needed. We account for equipment uncertainty, material variability, and repeatability to ensure reliable results. Scaling from lab scale trials to full production always presents challenges, conditions change, volumes increase, and materials behave differently, so maintaining close collaboration with production is essential for fine tuning and achieving consistent performance. We usually look forward to the real-world production on the line as this is the only way factors like extrusion behaviour can only be assessed on new mix designs.”

When asked about how his role drives innovation in the manufacturing and construction industries, Dr. Aldo Gallardo comments.  

“Our industry faces a major challenge of high Carbon dioxide (CO₂) footprint associated with cement and concrete production. At wienerberger, we are committed to decarbonisation and sustainable energy and that is why we are putting innovative structures in place, such as the fully electrified concrete tile facility in Smeed Dean, to reduce the impact of carbon dioxide in the environment. We explore technologies such as improved particle packing, new mixtures, and refined mix designs to decrease cement usage while increasing strength and durability. These solutions contribute to lower carbon concrete roof tiles without compromising performance. By optimising the way aggregates fit together, we reduce voids in the microstructure, which allows us to reduce cement content, directly contributing to lowering carbon emissions.” 

“My advice to the scientific community is for everyone to continue bridging the gap between academia and industry. By doing this, we can focus on applied research and experimental development that genuinely matters, research that drives improvements in industry, contributes to sustainability, and addresses some of the most important challenges we face globally.” – Dr. Aldo Fernando Sosa Gallardo, Concrete Technologist at wienerberger UK.

These insights from Dr. Aldo Gallardo highlight how science, engineering, and innovation come together every day at wienerberger. His contributions to the STEM and British Science communities are helping reshape the construction industry through new ideas, improved processes, and a commitment to building a more sustainable environment.

Happy British Science Week, from all of us at wienerberger UK & Ireland.