It seemed that the oyster shells in "Keke Cuo" were not selected by size or by following any rules, but it was found after careful analysis that the big shells were laid in stretcher bond (the overlap, which is usually of half the length of the object) whereas the small ones were laid in bull header bond (the overlap, which is usually of half the of width of the object).
The lower and upper shells were placed row by row in header bond to build a single-layered wall, or combined side by side to build a double-layered wall, both showing clear and obvious horizontal lines.
From inside to outside, the walls of "Keke Cuo" in Quanzhou are made up of 15 mm facing oyster shell mortar, 25 mm leveling mortar mixed with straw, 300-400 mm internal wall infilled with brick and rock debris, 30 mm rendering oyster shell mortar and 70-80 mm oyster shells laid in stretcher or bull header bond. The structure of "Oyster Shell House" in Guangzhou also includes several layers from inside to outside, namely 15 mm facing oyster shell mortar, 25 mm leveling mortar mixed with straw, 200-300 mm internal wall infilled with soil and gravel, 30 mm rendering oyster shell mortar and 200-300 mm oyster shells laid in bull header bond with joints unaligned.
The existing wall is to be taken down, the stone and coping will be made available to the contractor and can be recovered for reuse over a length of approx 850m.The contract will initially involve building a trial section of wall based on the specified standards, this will include the provision of additional masonry stone to provide a header bond
between exposed wall facings and additional coping stones to achieve the required wall profile.Particular emphasis will be placed on the quality and testing of mortar, as well as monitoring of bond patterns within the wall.The works will also involve effective traffic management and control during the works.