Since the Ming Dynasty, sticky rice has been the key ingredient in an incredibly strong mortar recipe, which has kept ancient buildings intact to this day. The rice-based mortar has also proven to be incredibly effective at sustaining earthquakes.
"Chemists now have discovered the ingredient in sticky rice that made the mortar so strong.
'Analytical study shows that the ancient masonry mortar is a kind of special organic-inorganic composite material,' the scientists explained. 'The inorganic component is calcium carbonate, and the organic component is amylopectin, which comes from the sticky rice soup added to the mortar. Moreover, we found that amylopectin in the mortar acted as an inhibitor: The growth of the calcium carbonate crystal was controlled, and a compact microstructure was produced, which should be the cause of the good performance of this kind of organic-organic mortar.'
To determine whether sticky rice can aid in building repair, the scientists prepared lime mortars with varying amounts of sticky rice and tested their performance compared to traditional lime mortar. The test results of the modeling mortars shows that sticky rice-lime mortar has more stable physical properties, has greater mechanical strength, and is more compatible, which make it a suitable restoration mortar for ancient masonry."
Images via Inhabitat.