Control of Cracking in Concrete Structures (Chapter 3)-Chapter 3 of ACI 224R-01, Control of Cracking in Concrete Structures (PDF)

Chapter 3 of ACI 224R-01, Control of Cracking in Concrete Structures (PDF)

Pdf Summary

The document titled "Control of Cracking in Concrete Structures" is a comprehensive report by the American Concrete Institute (ACI) and is intended to guide the evaluation and application of crack-control principles in concrete structures. It details the principal causes of cracking and recommends procedures for controlling it, focusing on various factors such as drying shrinkage, flexural members, overlays, and mass concrete construction.

Key topics addressed include:

1. <strong>Cracking Due to Drying Shrinkage</strong>: Drying shrinkage is described as the reduction in concrete volume triggered by water loss. The document explains that shrinkage, often restrained by construction elements like foundations or reinforcements, induces tensile stresses leading to cracking. The report emphasizes that while shrinkage is inevitable, its impact can be mitigated through good design and construction practices, such as using contraction joints and expanding cements.

2. <strong>Crack Control in Flexural Members</strong>: Different approaches and equations for controlling cracks in beams, slabs, and other structural elements subject to bending are presented. The mechanisms that cause these cracks and potential measures to address them, such as reinforcement and control joints, are outlined.

3. <strong>Long-term Effects and Environmental Factors</strong>: The document examines how elements like long-term loading, environmental conditions, aggregates, and polymers affect cracking over time.

4. <strong>Control Measures</strong>: The guidebook outlines various crack-control strategies, including the use of fiber-reinforced concrete, epoxy-based overlays, and proper construction practices to minimize unintended cracking and enhance durability.

5. <strong>Practical Recommendations</strong>: Readers receive practical advice on forming effective crack-control programs, emphasizing good construction practices to minimize restraint and control levels of visible cracking.

Overall, this edition of the ACI report, updated from its 1990 version, aims to assist professionals in reducing the adverse impacts of concrete cracking and ensuring structural integrity through scientific insights and practical recommendations.

Keywords

concrete cracking

drying shrinkage

flexural members

crack control

ACI report

reinforcement

construction practices

fiber-reinforced concrete

environmental factors

structural integrity