Characteristics of Beachrocks: A Review

Beachrocks are calcareous rocks that have been quite recently formed and are found in the intertidal zone on sandy beaches. The authors are developing an artificial rock with self-healing capabilities that can be used in coastal areas to repair the infrastructure of coastal walls. Because beachrocks are formed naturally on beaches, they merit study as a model for artificial rocks. We conducted a bibliographical study in order to gather information about the characteristics of beachrocks, which may aid in the manufacturing of artificial rocks. This study investigated their geographic distribution, formative periods, physical properties, and origins. The study found that over 90 % of beachrocks are found between the latitudes 40°N and the Tropic of Capricorn, and that their formative periods range from 26,000 years to just a few decades ago. We also learned that the cement component of beachrocks mainly consists of either calcium carbonate or silica. The dynamic characteristics of these components have been studied in only three papers, which note that their uniaxial compression strength ranges from as low as 6.0 to 42.0 MPa. Since very limited data are available on beachrocks in Japan where the artificial rock technology will first be deployed, there is a need for collecting additional data on their mechanical properties, elemental composition ratios, and mineral content.