Application of Natural Products to make Integral Water Repellent Concrete

A number of natural organic materials, such as wax, oil or fat has been used to impregnate porous building materials for thousands of years. During the long history of construction with mineral binders natural products such as egg white and animal blood have been added to the fresh mix of mortar and concrete to produce integral water repellent materials. The aim of the project presented in this contribution is to investigate the influence of addition of oxblood to the fresh mix of concrete on capillary suction of the hardened product and on chloride penetration. Conventional concrete with a water-cement ratio of o.5 has been prepared with addition of different amounts of ox blood. First it will be shown that capillary suction can be reduced significantly. In this way frost resistance and durability in direct contact with water can be improved. As a second step chloride penetration into this integral water repellent concrete has been determined. It was found that chloride penetration is slowed down considerably as compared to penetration of chloride into neat concrete. It will be shown that use of ox blood as a water repellent agent for concrete is an economical and at the same time an ecological technology to extend service life of reinforced concrete structures in aggressive environment.