Table 7 Formulations and craft techniques of admixtures in traditional lime-based mortars
Name | Primary use | Composition & processing method | Special notes |
|---|---|---|---|
I. Organic-modified systems | |||
Glutinous rice mortar (江米灰) | Construction of glazed floral ornaments; clamping of glazed tiles | Mix lime slurry with green pulp, add hemp cuttings, then mix in glutinous rice pulp and alum water. Lime : Hemp: Rice juice : Alum = 100: 4: 0.75: 0.5 | |
Oil-ash mortar (油灰) | Fine rammed floor tiles | Mix fine white lime powder, flour, glue paste and tung oil. White lime : Flour : Glue : Tung oil = 1: 2: (0.5–1): (2–3) | A small amount of alum water can be added |
Installation of brackets on column tops; pointing of balustrade stone works | Mix lime slurry with flour and tung oil. White lime : Flour : Tung oil = 1: 1: 1 | Should be harder for padding; should be thinner for pointing | |
Caulking for waterproofing engineering | Add tung oil to oil ash. Oil ash : Tung oil = 0.7: 1 | If hemp caulking is needed, the amount of hemp is 0.13 | |
Hemp-cut oil mortar (麻刀油灰) | Pointing of stacked stones; waterproof pointing of stone works | Add hemp cuttings into oil ash and pound evenly with a wooden stick. Oil ash : Hemp = 100: (3–5) | |
Blood-lime mortar (血料灰) | Construction of important bridges, revetments and other hydraulic structures | Dilute blood material and mix into lime mortar. Lime : Blood material = 100: 7 | |
II. Cellulosic-fiber finishes | |||
Paper-fiber mortar (纸筋灰) | Surface layer for indoor plastering; surface layer for sculpted flowers and plants | Soak straw paper in water to make pulp, put it into cooked mortar and stir well. Mortar: Pulp = 100: 5–6 | Thickness should not exceed 1–2 mm |
Reed-catkin mortar (蒲棒灰) | Surface layer for mural plastering | Add reed catkins into cooked mortar and stir well. Mortar: Reed catkins = 100: 3 | Thickness should not exceed 1–2 mm |
Straw-slurry mortar (滑秸灰) | Wall plastering | Cut straw into 5–6 cm lengths, add water and mix well. Slaked lime mortar: Straw = 100: 4 | Can only be used after the straw softens in a few days |
Cotton-lime mortar (棉花灰) | Surface layer for mural plastering | Add refined cotton wool into lime plaster and stir well. Mortar: Cotton = 100: 3 | Thickness should not exceed 2 mm |
Hairy mortar (毛灰) | Eaves plastering | Add animal bristles or human hair (length about 5 cm) into slaked lime mortar and stir well. Mortar: Hair = 100: 3 | |
III. Mineral-admixed renders | |||
Brick-face mortar (砖面灰) | Dry-laid, silk-jointed wall surfaces, fine-paved ground spotting | Add lime paste to ground brick. Ground brick : Lime paste = 3:7 to 7:3 | May be mixed with glue as appropriate |
Sawdust mortar (锯末灰) | Spotting and pointing of whitewashed wall; wall plastering | slaked lime, boiled lime paste or old lime paste with water; sieve and wash sawdust. Sawdust: Quicklime = 1: 1.5 (by volume); mix well and let stand for several days until sawdust softens before use | Sprinkled lime is suitable for outdoor use; Boiled lime mortar is suitable for indoor use |
Sand-lime mortar (砂子灰) | Wall plastering, mostly used for the base layer | Sieve sand; dilute lime paste with a small amount of water, then add sand and water to mix well. Sand : Lime = 1: 3 | |
Cinder ash mortar (焦渣灰) | Wall plastering; plastering cinder floors; applying cinder backing | Mix cinder with sprinkled lime and add water to blend, or add water to quicklime, extract the paste, and mix with cinder. Quicklime : Cinder = 1: 3 | Should be left to stand for 2 or 3 days before use to allow quicklime to slake and expand |
Coal-ball ash mortar (煤球灰) | Wall plastering | Crush and sieve thoroughly burned furnace ash; dilute lime paste or sprinkled lime with water, mix with furnace ash, and add water to blend. Quicklime paste : Fine furnace ash = 1: 3, mix well with water | |
Ternary mortar (三合灰) | Plastering base layer | Add an appropriate amount of cement to white-moon lime paste); hemp fibers may be added as needed | |
