Understanding Deterioration due to Salt and Ice Crystallization in Scandinavian Massive Brick Masonry

Kristin Balksten,Paulien Strandberg-De Bruijn

doi:10.3390/heritage4010022

Abstract

Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Highlights

The main aim of this article is to show in a pedagogic way the most common salts and crystals found in historic Scandinavian masonry buildings, to describe and illustrate how to use ocular methods to recognize them in macroscopic and microscopic scales and to describe their behaviour when causing damage. It seeks to provide an in-depth understanding of salt and frost-related damage and knowledge of how to repair and renovate brick masonry walls without causing additional damage
Since the early 13th century, brick masonry has been used for construction in the Scandinavian countries [1], using different construction techniques and with the quality of materials varying over time
Brick masonry buildings from the neo-Gothic period and to some extent in the neo-Romanesque style have proven to be extra problematic due to their construction method and choice of materials compared to, for example, medieval massive brick masonry buildings. It became clear at an early stage that poor quality bricks and lime mortar with high porosity and poor frost resistance and bricks containing sulphate had been used in the masonry core

Summary

Introduction

The main aim of this article is to show in a pedagogic way the most common salts and crystals found in historic Scandinavian masonry buildings, to describe and illustrate how to use ocular methods to recognize them in macroscopic and microscopic scales and to describe their behaviour when causing damage. It seeks to provide an in-depth understanding of salt and frost-related damage and knowledge of how to repair and renovate brick masonry walls without causing additional damage. An additional aim is to explore and present a possible new way to prevent or delay salt-related damage on internal masonry wall surfaces.

Objectives

Results

Conclusion