Bibliometric study of the application of gypsum residues and by-products in Portland cement and mortar

Gypsum is one of the most abundant natural minerals available in nature, and it can also be generated synthetically as a by-product of industrial processes. In this article, a review of previous studies is carried out that applied gypsum residues in cement hydration and as a partial substitute for cement and sand. For this, a survey was carried out in the databases: Science Direct, Scopus and Web of Science. It is verified that the chemical composition of several gypsum residues and by-products are similar, moreover their recycling does not change their composition. However, the type of calcium sulfate can interfere with the hydration reactions of tricalcium aluminate. Gypsum, when used in partial replacement of cement, reduces mechanical resistance, but when used with fly ash, it provides better long-term resistance. The apparent density values in the hardened state are reduced with the replacement of sand by gypsum. The compressive strength also decreases, but on the other hand, the flexural strength increases with the use of gypsum, this happened due to the free water content being higher when using gypsum, which was corroborated for cement hydration and resistance mechanics. Considering that there may be changes in the properties of both cement and mortar when using gypsum, studies still need to be carried out to evaluate the technological properties and its durability, moreover to this, a more in-depth analysis of the feasibility of adding gypsum to cement-based mortar is necessary recommended.

Automated summary

This article reviews previous studies on the use of gypsum residues in cement hydration and as a partial substitute for cement and sand. The chemical composition of gypsum residues and by-products are similar, and their recycling does not change their composition. However, the type of calcium sulfate can affect hydration reactions. When used as a partial replacement for cement, gypsum reduces mechanical resistance, but when used with fly ash, it provides better long-term resistance. The replacement of sand with gypsum decreases apparent density values and compressive strength, but increases flexural strength.