Performance of Brewery Digestate as a Potential Water Substitute in Concrete Applications

Concrete is one of the most utilised materials in the world. It is used to construct buildings, bridges and highways and is comprised of four key ingredients: cement, sand, gravel, and water. Although, there are environmental implications regarding the use of concrete, e.g. high embodied CO2, it is a flexible material in that it is possible to incorporate waste materials whilst maintaining structural integrity. Very little work has been done in replacing or partially substituting water as the hydration of cement is a key reaction to strength development. This paper investigates the possibility of utilising wastewater sludge (WWS) from the brewery industry as a water substitute in concrete. With the adverse effects of climate change resulting in water shortages around the world, there are sustainable implications of finding water substitutes. Experiments were carried out by supplementing water by volume in concrete mixes with WWS at 25%, 50%, and 100% steps at the point of need. Results were compared with a control specimen, which was made with 100% pure water. The results showed impressive compressive strengths that were suitable for structural applications, even at 100% WWS content. The results showed good repeatability and highlight the potential of WWS as a water replacement, which could enhance the sustainability aspect of concrete.