The influence of the addition of gypsum on some selected properties of lime-metakaolin mortars

J Majerova,R Drochytka

doi:10.1088/1757-899x/385/1/012034

Abstract

The renovation and replacement of historical plasters is still a very current topic. Today’s trend is for the production of dry mortar mixtures that can be used for the renovation of historic buildings. The article therefore focuses on the preparation of gypsum-modified lime-metakaolin mortar. An experiment consisted of two stages. In the first stage of the experiment, the basic technological properties of fresh and hardened mortars were examined (bulk density of fresh and hardener mortar, compressive and flexural strength). The second stage aimed at monitoring the hydration process in different environments. Environments should simulate real factors affecting the plaster (humidity, low and higher temperatures). To determinate of the phase composition, the X-ray diffraction analysis was used. The results showed that gypsum in the lime-metakaolin plaster caused an increase in compressive and flexural strength. The presence of gypsum also conduced to the formation of ettringite and this has caused volumetric changes.

Highlights

IntroductionAlmost all existing building materials (such as mortar, concrete and plaster mixtures) are designed using Portland cement
Almost all existing building materials are designed using Portland cement
Today’s trend is for the production of dry mortar mixtures that can be used for the renovation of historic buildings

Summary

Introduction

Almost all existing building materials (such as mortar, concrete and plaster mixtures) are designed using Portland cement. Portland cement is a modern binder and has been widely used only for the last hundred years, so it is not appropriate to use in the reconstruction of historical buildings. The materials used should be a combination of materials that best substitutes the original binders used [1]. The first lime paints and plasters date back to 7500 BC and come from the area of today’s Jordan. In Syria, gypsum was used as a wall finishing from as early as 7000 BC. These plasters were often decorated with paintings. The beneficial effect of the addition of ash from volcanic areas has been described by the Roman writer Marcus Vitruvius Pollio in his work Ten Books on Architecture [2,3,4]

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Conclusion