How Can Building Surveyors Efficiently Differentiate Between Asr and Sulphate Attack in Concrete in Buildings
Contents 1. Introduction 2 2. Concrete attacks 2 3. Alkali-Silica Reaction – ASR 3 4. Sulphate Attack 5 5. Reference List 8
1. Introduction
This report was issued in order to provide an in depth understanding of how a surveyor can differentiate between Alkali-Silica Reaction and Sulphate attacks in concrete when inspecting a building. In order to satisfy the requirements for this report, the author will give a detailed description of both kind of attacks, different study areas, experiments, diagnosis and forms of repair.
To be able to define and analyse this topic, the author of this report has used different sources of reference such as books, academic journals, World Wide Web and several British Standards.
By the end of this report, the writer will be able to demonstrate that the questioned concrete attacks can be differentiated by any professional surveyor when inspecting the concrete in a building. 2. Concrete attacks
Chemical attacks usually occurs when using poor quality cement although good concrete has been known to be subjected to conditions that can lead to its deterioration. The environment “supplies” several physical and chemical forces which can contribute to concrete deterioration.
BRE (2005) delivered a full list of chemical attacks that can arise both land contaminated by human and natural ground. There are several rarely occurred chemical attacks that are mainly caused by contaminated land; these are chemical species such as ammonium or chromium, but also organic such as phenols. The higher the quantity of these chemicals is, the higher the concrete attack. The most known forms of concrete attacks are: * Chloride penetration leading to corrosion of steel and spilling of the concrete cover; * Inadequate cover of reinforcing steel.
Less common causes of concrete deterioration caused by chemicals or chemical reaction are: * Cycles of freezing and thawing; * Carbonation resulting in an increase
1. Introduction
This report was issued in order to provide an in depth understanding of how a surveyor can differentiate between Alkali-Silica Reaction and Sulphate attacks in concrete when inspecting a building. In order to satisfy the requirements for this report, the author will give a detailed description of both kind of attacks, different study areas, experiments, diagnosis and forms of repair.
To be able to define and analyse this topic, the author of this report has used different sources of reference such as books, academic journals, World Wide Web and several British Standards.
By the end of this report, the writer will be able to demonstrate that the questioned concrete attacks can be differentiated by any professional surveyor when inspecting the concrete in a building. 2. Concrete attacks
Chemical attacks usually occurs when using poor quality cement although good concrete has been known to be subjected to conditions that can lead to its deterioration. The environment “supplies” several physical and chemical forces which can contribute to concrete deterioration.
BRE (2005) delivered a full list of chemical attacks that can arise both land contaminated by human and natural ground. There are several rarely occurred chemical attacks that are mainly caused by contaminated land; these are chemical species such as ammonium or chromium, but also organic such as phenols. The higher the quantity of these chemicals is, the higher the concrete attack. The most known forms of concrete attacks are: * Chloride penetration leading to corrosion of steel and spilling of the concrete cover; * Inadequate cover of reinforcing steel.
Less common causes of concrete deterioration caused by chemicals or chemical reaction are: * Cycles of freezing and thawing; * Carbonation resulting in an increase