Cement production relies heavily on limestone and energy-intensive processing, and it drives major carbon emissions and water use. Researchers at the University of Delaware are working on a different path: clay-based materials called geopolymers that behave like cement, now moving beyond small laboratory samples and into brick forms.
Over the summer, undergraduate researcher Conner Nelms has been helping scale the geopolymer process using locally sourced clays. The team is working with two clays collected from White Clay Creek State Park, a white clay and a red clay. Nelms described the material as closer to dense soil than pottery clay, with rocks and organic material mixed in.
The lab’s testing shows a clear difference between the two sources. The red clay’s iron oxide gives it color, but it also interferes with the geopolymer reaction, resulting in weaker samples. The white clay has delivered stronger results so far, making it the focus as the work moves into larger sample sizes.
Day to day, Nelms mixes raw materials, casts small one-centimeter cubes, and cures them under controlled conditions while adjusting liquid-to-solid ratios. He is also comparing curing methods, including ambient and sealed curing, since water plays an essential role in the reaction. Next, the project moves from one-centimeter cubes to two-inch cubes and compares performance with traditional sand-based mixes, using compressive strength as the key measure.
For mason contractors tracking low-carbon material trends, this type of research signals what to watch for when new “brick-like” units or binders enter the market: clear compressive strength data, curing requirements, and consistency from one raw material source to another. Nelms also noted the lab is building a machine-learning model to predict compressive strength based on composition, and that effort depends on reliable test data.
Read the full, original article from University of Delaware here.