Sticky-rice lime mortar
Mortero de cal y arroz glutinoso
- Date
- c. 450 · confidence low
- Place
- Nanjing, Jiangsu, China
- Credited to
- Builders of the Southern and Northern dynasties
- Field
- Matter & energy
⚠️ Disputed: the sources disagree.
What it is
A slaked-lime mortar with glutinous rice soup added, whose amylopectin controls calcium carbonate crystallisation and yields a denser, stronger, waterproof binder. It was used in tombs, pagodas, dykes and city walls.
Chemical analysis (Zhang Bingjian and colleagues, 2010) identified it in Southern and Northern dynasties tombs and the Ming wall of Nanjing; the date of first use remains open. Starch additives occur in other cultures too.
What it led to
- highly durable city walls and tombs
- heritage repair with organic-inorganic mortar
- modern composite mortars with organic additives