Characterization of Cement-Based Mortars Chemically Active (Gyspe And Plaster) By Design of Experiments Methods

Abstract

The sulfatic activation method (gypsum and plaster) of the various slag cements activates the hydration process and modifies the particle size at the initial ages of hydration. The main objective of this experimental study is to analyze the influence of mineral activator, gypsum and plaster (chemical effect) on the physicochemical properties of three types of cements with mineral addition (slag). Also, the mechanical responses of mortar (compressive and flexural strengths) were studied. In the present experimental work two types of gypsum activating agent (CaSO4.2H2O) and plaster (CaSO4.0.5H2O) in different assays (0%, 2% and 4%) by the substitution method in relation to the weight of the cement were used. A factorial analysis of the results using the experimental design method (JMP) was the subject of this study. The results obtained by this activation showed a significant effect on the physical properties; great finesse, reduced setting times (start and end of setting) and increased need for fresh water. In conclusion, this activation is beneficial for the development of mechanical resistance (compression and flexion) of short-term activated mortars as well as acceptable medium and long-term values in the cured state. The numerical results were compared using anterior results developed in our laboratory. The good agreements confirm the validity of the numerical method.