Moisture

Author: Hans-Jürgen Schwarz

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Overview of the chapters on moisture

• Physical Principles of Moisture
  • Equilibrium Moisture
  • Vapor Sorption
  • Water Absorption Coefficient
• Moisture Measurement
• Units for Moisture Measurement

Introduction

Moisture content is an important parameter for the assessment of salt deterioration. It should therefore always be determined.

Several factors influence the water content of a material:

• The Materials themselves: Depending on their chemical composition, porosity, inner surface areas and texture, each material has a different capacity to sorb moisture, both from water vapor in the air (adsorption) or as liquid water (absorption).
• The Relative Humidity of the air: The higher the relative humidity, the higher the amount of moisture adsorbed by the material.
• Liquid Water Uptake: The presence of capillary pores in a material induces capillarity of liquid water when the surface is wetted by rain, fog, dew or in contact with a damp body, i.e., soils in the case of a building. In general, larger amounts of liquid water can be absorbed as compared to water vapor adsorption.