🧱 The secret ingredient holding the Great Wall of China together is sticky rice.
Ming Dynasty masons (1368-1644) mixed boiled sticky rice soup into their lime mortar. The result was a tough, flexible, water-resistant binder that has held brick sections together for around 600 years.
The chemistry: sticky rice is packed with amylopectin, a complex starch. In 2010, chemists led by Bingjian Zhang at Zhejiang University found that amylopectin acts as a template, steering calcium carbonate crystals into a dense, interlocking structure instead of large brittle chunks.
That compact microstructure is why some wall sections have shrugged off earthquakes and still keep weeds out of the seams centuries later.
Read more:
https://pubs.acs.org/doi/abs/10.1021/ar9001944
https://www.nationalgeographic.com/history/article/100608-sticky-rice-mortar-china-science
https://www.sciencedaily.com/releases/2010/05/100530093704.htm
