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6. Water – Requirements and Impurities

Water is integral to construction, influencing hydration, workability, and curing of concrete. Not all water is suitable; impurities can adversely affect material quality, durability, and strength. The chapter addresses necessary water requirements for construction, effects of impurities, acceptable limits, testing methods, and sustainable practices.

Sections

Water – Requirements and Impurities

This section highlights the critical role of water in construction, emphasizing the requirements for different uses and the implications of impurities on concrete quality.

6 Section Overview

Start current section content and materials

6.1 Requirements of Water for Construction

Water is critical for construction, but it must be free from impurities to ensure material integrity.

6.1.1 For Mixing Concrete

This section outlines the specific requirements and quality standards of water used for mixing concrete in construction.

6.1.2 For Curing Concrete

Curing water is essential for maintaining moisture in concrete to facilitate hydration without harmful impurities.

6.1.3 For Cleaning Construction Equipment

Water used for cleaning construction equipment must be free from contaminants that could harm the equipment or surrounding materials.

6.2 Effects of Impurities in Water

Impurities in water negatively impact the quality and durability of concrete and reinforcement structures in construction.

6.2.1 Effect on Setting Time

Impurities in water used for construction can significantly affect the setting time of concrete, with substances like sugars delaying setting and acids causing rapid setting.

6.2.2 Effect on Strength

This section discusses how impurities in water, particularly chlorides and sulphates, can adversely affect the strength of concrete.

6.2.3 Effect on Reinforcement Steel

The presence of impurities in water can lead to significant detrimental effects on the corrosion resistance and durability of reinforcement steel used in concrete.

6.2.4 Effect on Durability

The durability of concrete and structures can be severely impacted by impurities in water, particularly sulphates, alkalies, and salts.

6.3 Common Impurities Found in Water

This section outlines the common impurities found in water that can negatively impact the quality and durability of construction materials.

6.3.1 Suspended Solids

Suspended solids in water, such as clay and organic matter, can negatively impact concrete quality by increasing water demand and affecting bond strength.

6.3.2 Dissolved Solids

Dissolved solids in water, such as salts and minerals, can significantly impact the suitability of water for construction purposes.

6.3.3 Organic Matter

Organic matter in water can negatively impact the hydration and strength of concrete materials used in construction.

6.3.4 Oils and Greases

Oils and greases in water can severely inhibit bonding in concrete and affect its workability.

6.3.5 Acids and Alkalis

This section discusses the impact of acids and alkalis on the durability and integrity of cementitious materials and reinforcement steel in construction.

6.4 Acceptable Limits for Impurities

This section outlines the permissible limits for various impurities in water used in construction, as per IS: 456-2000.

6.5 Testing of Water for Construction Use

This section discusses the testing methods to determine the suitability of water for construction use, highlighting essential tests for pH, chemical composition, setting time, and compressive strength.

6.5.1 pH Test

The pH test determines the acidity or alkalinity of water, essential for ensuring its suitability in construction.

6.5.2 Chemical Analysis

Chemical analysis is essential to assess the quality of water for construction, focusing on identifying harmful impurities.

6.5.3 Setting Time Comparison Test

The Setting Time Comparison Test assesses the impact of using different types of water on the setting time of cement compared to distilled water.

6.5.4 Compressive Strength Test

The Compressive Strength Test evaluates the strength of concrete made with test water, ensuring it meets at least 90% of the strength of that made with distilled water after a week.

6.6 Sources of Water and Their Suitability

This section discusses different sources of water used in construction and evaluates their suitability based on impurity levels.

6.6.1 Tap Water (Municipal Supply)

Tap water is generally suitable for construction but requires testing for large projects to ensure safety and compliance.

6.6.2 Groundwater (Wells and Borewells)

This section discusses groundwater sources such as wells and borewells and highlights their suitability for construction uses, particularly in terms of water quality.

6.6.3 River and Surface Water

River and surface water may have various impurities affecting their suitability for construction uses, necessitating careful evaluation and testing.

6.6.4 Sea Water

Sea water is generally unsuitable for concrete use, particularly reinforced concrete, due to high chloride levels.

6.7 Treatment Methods for Impure Water

This section discusses various treatment methods necessary to purify impure water before its use in construction.

6.7.1 Filtration

Filtration is a crucial treatment method to improve water quality by removing suspended particles and organic debris, making it suitable for construction use.

6.7.2 Neutralization

Neutralization in this context refers to the treatment of acid and alkaline impurities in water to make it suitable for construction.

6.7.3 Distillation or Reverse Osmosis

This section discusses the treatment methods of distillation and reverse osmosis to purify water, specifically addressing their roles in removing salts and dissolved solids.

6.7.4 Aeration and Settling

Aeration and settling are crucial treatment methods that improve water quality by removing volatile organic compounds and allowing suspended particles to settle.

6.8 Practical Considerations in Construction Projects

This section addresses the challenges and best practices regarding water usage in construction projects.

6.8.1 Water Availability at Site

This section discusses the importance of water availability at construction sites, specifically in remote areas, and emphasizes the necessity of testing water quality prior to its usage.

6.8.2 Storage and Handling of Water

In this section, we discuss the best practices for storing and handling water in construction to prevent contamination and ensure quality.

6.8.3 Water Use in Different Weather Conditions

This section discusses how weather conditions impact the requirements for water use in construction activities.

6.9 IS Codes and International Standards

This section outlines the importance of adhering to IS Codes and international standards in ensuring the quality and safety of construction water.

6.9.1 Indian Standards (IS)

This section discusses the Indian Standards (IS) related to the quality of water used in construction and their importance in ensuring structural integrity.

6.9.2 International Standards

This section outlines key international standards related to the use of water in concrete production, emphasizing the importance of compliance for safety and structural integrity.

6.10 Case Studies of Water-Related Failures

This section presents two case studies that highlight water-related failures in construction projects, emphasizing the importance of water quality.

6.11 Environmental and Sustainability Aspects

This section discusses eco-friendly practices in water use for construction, emphasizing recycling and rainwater harvesting.

6.11.1 Recycled Water Use

Revised water sources, particularly treated greywater, can be effectively reused in construction after meeting specific quality standards.

6.11.2 Rainwater Harvesting

Rainwater harvesting involves collecting and storing rainwater for use, reducing reliance on other water sources.

6.11.3 Water Footprint of Concrete

The water footprint of concrete refers to the amount of water required to produce concrete, emphasizing the quantity and importance of water management in concrete manufacturing.

6.12 Field Guidelines for Engineers and Supervisors

Engineers and supervisors should adhere to specific guidelines regarding water quality management during construction to ensure the integrity and durability of concrete.

Learning Objectives

  • Water used in construction must be free of impurities to ensure quality and strength.

  • Different types of water have varying suitability based on local sources and required tests.

  • Sustainable practices include the use of recycled and harvested rainwater to reduce environmental impact.

Key Concepts

Impurities in Water

Substances such as salts, organic matter, and chemicals in water that can adversely affect concrete quality.

Testing Methods

Procedures to assess water quality, including pH testing, chemical analysis, and strength comparison tests.

Recycled Water Use

Utilization of treated greywater or wastewater in construction, complying with safety standards for non-structural applications.

Practice Exercises

Total Questions

2

Estimated Time

4 min

Passing Score

70%

Instructions

  • Read each question carefully
  • You can use hints if you need help
  • Complete all questions before submitting
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