ABSTRACT
Casein, an organic milk protein, was used extensively in masonry mortars centuries ago. It was understood to improve workability, however, little information is available on its effects on material strength. Casein is non-toxic, has minimal environmental impacts, and has no reported health hazards.Mortar prisms were cast for compressive, tensile, flexural and shear tests. Brick-to-mortar bond strength tests were conducted in flexure and in shear. It was found that adding 0.5% casein by mass yielded a flowable mortar, however, a 75% reduction in strength resulted. Contrarily, brick-to-mortar bond strength substantially improved.In mortar repair, it has been deemed critically important to appropriately specify mortar with a material strength compatible with both the brick and the original mortar. Casein protein acted as a superplasticizer if 0.5% by mass was added. The application of casein mortar is plausible for repointing work. It may also be injected between wythes to stabilise a wall.
