Potential use of marine mollusk shells in cementitious compounds: A brief review

Alongside the technological, social, and economic development of the construction industry, a growing demand for materials to serve this sector is a cause for concern and increases the need for alternatives. The environmental impacts resulting from the production of cement and other binders, as well as the enormous volumes of natural aggregates extracted from their deposits, for example, have motivated studies worldwide in search of solutions. Among these initiatives, the development of safe constituents for incorporation into cementitious compounds has been the objective of several studies. One of the most promising solutions, which has motivated numerous studies in recent years, is the shells of marine mollusks. This paper, therefore, presents a literature review on the main uses of materials derived from the processing of mollusk shells in cementitious compounds, such as mortars and concrete. In addition to presenting some general characteristics of mollusk shells, this study used the available literature to investigate the main types of shells used, their properties, and the influences resulting from their incorporation into cementitious compounds, primarily in the form of aggregates, powdered, and/or calcined. It was found that in most cases, the addition of the biomaterial in question reduced workability and density but increased mechanical strength. Thus, we can conclude that shells have significant potential as alternative constituents for the production of sustainable cementitious compounds. However, the application of this biomaterial in low proportions proved to be the most viable solution in most cases properties.