Practical Concrete Mix Design

Avijit Chaubey

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9781000767247
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Practical Concrete Mix Design has been compiled to help readers understand the concrete mix design methodology, including formulas and tables involved in the pertinent steps. This book helps engineers understand the mix design procedure, through illuminating every possible explanation for each step of mix design, limitations given by standards, and practical guides on tailor-making concrete to meet specific requirements. The construction industry needs engineers/experts who can reduce the costs of concrete, and thereby increase their profitability. This book shows effective methods for optimizing concrete and simultaneously achieving the desired properties of concrete. It covers why, how, and when with respect to concrete proportioning and optimization. It further provides the necessary skills for engineers to hone their skills in doing so, understanding the risks involved, and troubleshooting related problems.

1

Concrete Mix-Proportioning General Concepts

1.1 Introduction

Concrete is a mixture of cementitious materials, which binds its fillers together to form a structure that fulfills the requirements that the user desires in terms of strength, workability, economy and longevity.

The main challenge faced by a concrete designer is to match the concrete properties with the requirements of the user by finding proportions of the available materials. The challenges only increase from here as, 1). The materials used in concrete except for cement and admixture are mostly uncontrolled and are prone to high variation in terms of their properties. 2)The use of materials for the manufacture of concrete is guided by their availability, client specification, and cost restrictions. Thus most ideal material practically is never available. 3) Concrete has been referred to as the most complex material known to humans. If we see any other material, be it steel or the microchips we use in computers, none of these materials contain more than four elements, whereas concrete contains cement, which itself has more than seven elements, and if any of these elements vary even by small percentage, it can lead to huge variation in concrete property – not to mention the other materials of concrete and their innate property of variation.

Designing concrete is a science and also an art, which improves when mixes are actually designed and tested for practical applications and then troubleshot. This science incorporates concepts of chemistry, statistics, and physical material properties. Numerous methods have been developed over the years, and each of them has its advantages and disadvantages or limits of application for a purpose.

Design of concrete mixes involves determining the proportions of the given constituents, namely, cement, water, coarse and fine aggregates, and admixtures, if any, which would produce concrete possessing the specified properties both in the fresh and hardened states with the maximum overall economy. Workability is the most important property specified in the fresh state; for the hardened state, compressive strength and durability are important. The design of concrete mixes is accomplished by the use of certain relationships established from experimental data, which affords a reasonably accurate guide to select the best combination of ingredients to achieve the desirable properties.

To learn concrete mix proportioning we need to remember these two statements:

a. The compressive strength of concrete is governed only by its water cement ratio.

b. For a given aggregate characteristics, the workability of concrete is governed by its water content.

From these statements it should not be inferred that cement content is only related to strength of concrete, but that workability also plays a vital role in deciding the cement content. Moreover, people tend to confuse water cement ratio and water content and their significance; the same thing should also be understood well during understanding the mix-proportioning process.

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Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Foreword
• Preface
• Author
• 1. Concrete Mix-Proportioning General Concepts
• 2. Proportioning Concretes: Rapid Method
• 3. ACI Method of Proportioning Concretes
• 4. DOE Method of Proportioning Concretes
• 5. BRMCA Method of Proportioning Concretes
• 6. Unconventional Proportioning Methods and Special Concretes
• 7. Optimization of Concrete
• 8. Conducting Laboratory Tests and Validation of Mixes
• Bibliography
• Index