With a clay paste containing 5 percent spent grains, the team was able to create bricks just as strong as the conventional type, while reducing the amount of heat they lost by 28 percent.
Build better bricks with this beer brewing byproduct
— By Janet Fang on December 4, 2013, 9:53 PM PST
It almost sounds like this makes a low-grade firebrick -- the heat-resistant bricking used in fireplaces and other places that must deal with high temperatures without cracking. I can see this material (clay mixed with spent grains) being used in a number of sustainable building areas, such as cob or as the coating for the heating portion of a rocket heater. Another option would be to make emergency drip water filters (although that would probably require increasing the mix to 10% grains and firing at a lower temperature, such as 400-500 degrees Celsius.)
Just some off-the-cuff thoughts in case there are any materials science students looking for a class project.