Construction Materials and Testing PDF

(i) Construction Materials and Testing Author Dr. Vanita Aggarwal Professor and Head Department of Civil Engineering Maharishi Markandeshwar (Deemed to be University) Mullana (Ambala), Haryana...

(i) Construction Materials and Testing Author Dr. Vanita Aggarwal Professor and Head Department of Civil Engineering Maharishi Markandeshwar (Deemed to be University) Mullana (Ambala), Haryana Reviewer Dr. A.D. Prasad Assistant Professor Department of Civil Engineering National Institute of Technology Raipur, Chhattisgarh All India Council for Technical Education Nelson Mandela Marg, Vasant Kunj, New Delhi, 110070 (ii) BOOK AUTHOR DETAILS Dr. Vanita Aggarwal, Professor and Head, Department of Civil Engineering, Maharishi Markandeshwar (Deemed to be University), Mullana (Ambala), Haryana. Email ID: [email protected] BOOK REVIEWER DETAIL Dr. A.D. Prasad, Assistant Professor, Department of Civil Engineering, National Institute of Technology, Raipur, Chhattisgarh Email ID: [email protected] BOOK COORDINATOR (S) – English Version 1. Dr. Ramesh Unnikrishnan, Advisor-II, Training and Learning Bureau, All India Council for Technical Education (AICTE), New Delhi, India Email ID: [email protected] Phone Number: 011-29581215 2. Dr. Sunil Luthra, Director, Training and Learning Bureau, All India Council for Technical Education (AICTE), New Delhi, India Email ID: [email protected] Phone Number: 011-29581210 3. Sh. M. Sundaresan, Deputy Director, Training and Learning Bureau, All India Council for Technical Education (AICTE), New Delhi, India Email ID: [email protected] Phone Number: 011-29581310 November, 2023 © All India Council for Technical Education (AICTE) ISBN : 978-81-963773-9-7 All rights reserved. No part of this work may be reproduced in any form, by mimeograph or any other means, without permission in writing from the All India Council for Technical Education (AICTE). Further information about All India Council for Technical Education (AICTE) courses may be obtained from the Council Office at Nelson Mandela Marg, Vasant Kunj, New Delhi-110070. Printed and published by All India Council for Technical Education (AICTE), New Delhi. Attribution-Non Commercial-Share Alike 4.0 International (CC BY-NC-SA 4.0) Disclaimer: The website links provided by the author in this book are placed for informational, educational & reference purpose only. The Publisher do not endorse these website links or the views of the speaker / content of the said weblinks. In case of any dispute, all legal matters to be settled under Delhi Jurisdiction, only. (iii) (iv)  ACKNOWLEDGEMENT The author is grateful to the authorities of AICTE, particularly Prof. T. G. Sitharam, Chairman; Dr. Abhay Jere, Vice-Chairman; Prof. Rajive Kumar, Member-Secretary; Dr. Ramesh Unnikrishnan, Advisor-II and Dr. Sunil Luthra, Director, Training and Learning Bureau, for their planning to publish the books on Civil Engineering. I sincerely acknowledge the valuable contributions of the reviewer of the book Prof. A.D. Prasad, Civil Engineering, NIT Raipur for his valuable inputs to enhance the quality and better shape the book to make it student friendly. My special thanks are due to MM (DU), Mullana officials for providing constant moral support, and encouragement. I want to thank my supporting staff Mr. Harpreet to help me draft the manuscript. I also thank all my students and fellow faculty members for inspiring me during my years of service, learnings from which have proved valuable in publishing the contents of this book. I would like to express my deepest thanks to my husband Dr. Viney Aggarwal whose motivation has been with me throughout this noble journey. I wish to express my gratitude to my children, Priysha and Manit for their unconditional love, care, and strength which allowed me to finish our book successfully. Last, but definitely not the least, I would like to dedicate this book to my father, Late Sh. Kalwant Rai whose teachings abled me to reach this position today. This book is an outcome of various suggestions of AICTE members, experts and authors who shared their opinions and thoughts to further develop the engineering education in our country. Acknowledgements are due to the contributors and experts in this field whose published books, review articles, papers, photographs, footnotes, references and other valuable information enriched me at the time of writing the book. I hope this book will help civil engineering students understand the subject easily and conveniently. Dr. Vanita Aggarwal (v)  PREFACE The book titled “Construction Materials and Testing” is an outcome of the extensive experience of my teaching of Building Construction Materials and Drawing, and Concrete Technology courses and allied research work carried out on construction materials. The purpose of writing this book is to provide deep knowledge of construction materials to the students and professionals in Civil Engineering. Keeping in mind the purpose of wide coverage as well as to provide essential supplementary information, the topics recommended by AICTE have been included, in a very systematic and orderly manner throughout the book. Efforts have been made to explain the fundamental concepts of the subject in the simplest possible way. During the process of preparation of the manuscript, various standard textbooks have been referred thoroughly and accordingly the sections like multiple choice questions, short and long answer questions and practical exercises have been framed. While preparing the different sections, emphasis has also been laid on definitions and principles of selection of appropriate material for the desired application. As the subject is more about real life application of construction materials, many examples of practical projects have been discussed in “Know More” section. The book covers all types of details of building construction materials required for a Civil Engineer and these have been presented in a very logical and systematic manner. Apart from illustrations, examples and exercises as required, the book has been enriched with numerous QR codes describing additional details for the curious minds. The book is written in a way that it ignites the inquisitive approach of its readers. It explains the fundamental concepts, material characteristics and related laboratory experiments on natural, artificial, waste-based and specially processed building construction materials. This will enable students to contribute creatively to infrastructure projects throughout the whole construction process, from the foundation to the finished structure. It is expected that the book is easy to comprehend and will inspire civil engineering fraternity at large to learn and apply suitable construction material at all times. This will surely contribute to the development of a solid foundation of the subject. All beneficial comments and suggestions that will contribute to the improvement of future editions of the book are always welcome and may be sent to [email protected]. It is an immense pleasure to publish this book for the benefit of teachers, students, and civil engineering professionals. Dr. Vanita Aggarwal (vi)  OUTCOME BASED EDUCATION For the implementation of an outcome based education the first requirement is to develop an outcome based curriculum and incorporate an outcome based assessment in the education system. By going through outcome based assessments, evaluators will be able to evaluate whether the students have achieved the outlined standard, specific and measurable outcomes. With the proper incorporation of outcome based education there will be a definite commitment to achieve a minimum standard for all learners without giving up at any level. At the end of the programme running with the aid of outcome based education, a student will be able to arrive at the following outcomes: Programme Outcomes (POs) are statements that describe what students are expected to know and be able to do upon graduating from the program. These relate to the skills, knowledge, analytical ability attitude and behaviour that students acquire through the program. The POs essentially indicate what the students can do from subject-wise knowledge acquired by them during the program. As such, POs define the professional profile of an engineering diploma graduate. National Board of Accreditation (NBA) has defined the following seven POs for an Engineering diploma graduate: PO1. Basic and Discipline specific knowledge: Apply knowledge of basic mathematics, science and engineering fundamentals and engineering specialization to solve the engineering problems. PO2. Problem analysis: Identify and analyses well-defined engineering problems using codified standard methods. PO3. Design/ development of solutions: Design solutions for well-defined technical problems and assist with the design of systems components or processes to meet specified needs. PO4. Engineering Tools, Experimentation and Testing: Apply modern engineering tools and appropriate technique to conduct standard tests and measurements. PO5. Engineering practices for society, sustainability and environment: Apply appropriate technology in context of society, sustainability, environment and ethical practices. PO6. Project Management: Use engineering management principles individually, as a team member or a leader to manage projects and effectively communicate about well-defined engineering activities. PO7. Life-long learning: Ability to analyse individual needs and engage in updating in the context of technological changes. (vii)  COURSE OUTCOMES After completion of the course the students will be able to: CO-1: Identify relevant construction materials. CO-2: Identify relevant natural construction materials. CO-3: Select relevant artificial construction materials. CO-4: Select relevant special type of construction materials. CO-5: Identify and use of processed construction materials Mapping of Course Outcomes with Programme Outcomes to be done according to the matrix given below: Expected Mapping with Programme Outcomes (1- Weak Correlation; 2- Medium correlation; 3- Strong Correlation) Course Outcomes PO-1 PO-2 PO-3 PO-4 PO-5 PO-6 PO-7 CO-1 3 1 2 2 3 4 1 CO-2 2 1 3 3 3 2 1 CO-3 2 1 2 3 3 2 1 CO-4 1 2 3 3 3 1 2 CO-5 1 2 2 2 3 3 2 (viii)  GUIDELINES FOR TEACHERS To implement Outcome Based Education (OBE) knowledge level and skill set of the students should be enhanced. Teachers should take a major responsibility for the proper implementation of OBE. Some of the responsibilities (not limited to) for the teachers in OBE system may be as follows: Within reasonable constraint, they should manoeuvre time to the best advantage of all students. They should assess the students only upon certain defined criterion without considering any other potential ineligibility to discriminate them. They should try to grow the learning abilities of the students to a certain level before they leave the institute. They should try to ensure that all the students are equipped with the quality knowledge as well as competence after they finish their education. They should always encourage the students to develop their ultimate performance capabilities. They should facilitate and encourage group work and team work to consolidate newer approach. They should follow Blooms taxonomy in every part of the assessment. Bloom’s Taxonomy Teacher should Student should be Possible Mode of Level Check able to Assessment Students ability to Create Design or Create Mini project create Students ability to Evaluate Argue or Defend Assignment justify Students ability to Differentiate or Project/Lab Analyse distinguish Distinguish Methodology Students ability to Operate or Technical Presentation/ Apply use information Demonstrate Demonstration Students ability to Understand Explain or Classify Presentation/Seminar explain the ideas Students ability to Remember Define or Recall Quiz recall (or remember) (ix)  GUIDELINES FOR STUDENTS Students should take equal responsibility for implementing the OBE. Some of the responsibilities (not limited to) for the students in OBE system are as follows: Students should be well aware of each UO before the start of a unit in each and every course. Students should be well aware of each CO before the start of the course. Students should be well aware of each PO before the start of the programme. Students should think critically and reasonably with proper reflection and action. Learning of the students should be connected and integrated with practical and real life consequences. Students should be well aware of their competency at every level of OBE. (x)  ABBREVIATIONS AND SYMBOLS List of Abbreviations General Terms Abbreviations Full form Abbreviations Full form ACB Aerated Concrete Blocks NaOH Sodium Hydroxide Al2O3 Alumina OPC Ordinary Portland Cement B2O3 Boron Oxide POP Plaster of Paris BIS Bureau of Indian Standards PPC Portland Pozzolana Cement CaO Calcium Oxide PPF Polypropylene Fibers DPC Damp Proof Coarse PUR Polyurethane Foam Fe2O3 Iron Oxide PVC Poly-Vinyl Chloride FRC Fibre Reinforced Concrete RCC Reinforced Cement Concrete Ground Granulated Blast GGBS RHC Rapid Hardening Cement Furnace Slag Glass fibres Reinforced GRC SCBA Sugar Cane Bagasse Ash Concrete MgO Magnesium Oxide SiO2 Silica Na2SiO3 Sodium Silicate SO3 Sulphur Oxide (xi)  LIST OF FIGURES Unit 2 Natural Construction Materials Fig. 2.1 : Tools for Dressing of Stones 23 Fig. 2.2 : Structure of Timber 24 Fig. 2.3 : Defects in Timber 28 Unit 3 Artificial Construction Materials Fig. 3.1 : A Standard Brick 56 Fig. 3.2 : Wet Process for cement manufacturing 59 Fig. 3.3 : Dry Process for cement manufacturing 60 Fig. 3.4 : A standard hollow block 63 (xii)  LIST OF TABLES Unit 2 Natural Construction Materials Table 2.1 – Desirable limits for Properties of Good Building Stone 20 Unit 3 Artificial Construction Materials Table 3.1 - Comparison of Bricks and Aerated Concrete Blocks 52 Table 3.2 - Comparison of various types of burnt bricks 54 Table 3.3 - Function of Each Ingredient of Cement 58 Unit 5 Processed Construction Materials Table 5.1 - Comparison between Artificial and Natural Sand 110 (xiii)  CONTENTS Foreword iv Acknowledgement v Preface vi Outcome Based Education vii Course Outcomes viii Guidelines for Teachers ix Guidelines for Students x Abbreviations and Symbols xi List of Figures xii List of Tables xiii Unit 1: Overview of Construction Materials 1-16 Unit specifics 1 Rationale 1 Pre-requisites 2 Unit outcomes 2 1.1 Scope of Construction Materials 3 1.1.1 Construction Material in Building Construction 3 1.1.2 Construction Material in Transportation Engineering 3 1.1.3 Construction Material in Environmental Engineering 4 1.1.4 Construction Material in Irrigation Engineering 4 1.2 Selection of Materials 4 1.2.1 Factors Affecting Selection of Material 5 1.2.2 Selection Materials on the Basis of Strength 5 1.2.3 Selection of Materials on the Basis of Durability 6 1.2.4 Selection of Materials on their Eco-friendly Nature 6 1.2.5 Selection of Materials on Basis of Economy 6 1.3 Classification of Materials 7 1.3.1 Natural Building Materials 7 1.3.1.1 Rocks 7 1.3.1.2 Clay 7 1.3.1.3 Sand 8 1.3.1.4 Timber 8 1.3.2 Artificial Building Materials 8 1.3.2.1 Concrete 8 (xiv)  1.3.2.2 Bricks 8 1.3.2.3 Steel 8 1.3.2.4 Glass 8 1.3.2.5 Artificial Sand 8 1.3.2.6 Plastic 8 1.3.3 Special Construction Materials 9 1.3.3.1 Poly-Vinyl Chloride (PVC) 9 1.3.3.2 Polypropylene Fibres (PPF) 9 1.3.3.3 Emulsions and Paints 9 1.3.4 Finishing Materials 9 1.3.4.1 Lime Plaster 9 1.3.4.2 Plaster of Paris (POP) 9 1.3.5 Recycled Materials 9 Unit summary 10 Exercises 10 Practical 13 Know more 15 References and suggested readings 15 Some Inquisitive Examples 16 Unit 2: Natural Construction Materials 17-46 Unit specifics 17 Rationale 17 Pre-requisites 18 Unit outcomes 18 2.1 Building Stones 19 2.1.1 Good Building Stone 19 2.1.2 Requirements of Good Building Stone 20 2.1.3 Quarrying of Building Stones 20 2.1.3.1 Methods and Tools of Quarrying 20 2.1.4 Dressing of Stones 21 2.1.4.1 Methods of Dressing of Stone 21 2.1.5 Tools used for Dressing of Stones 21 2.2 Timber 23 2.2.1 Structure of Timber 23 2.2.2 General Properties of Good Timber 24 2.2.3 Seasoning of Timber 25 2.2.3.1 Advantages of Seasoning 25 2.2.3.2 Methods of Seasoning 25 2.2.4 Defects in Timber 26 (xv)  2.2.5 Bamboo in Construction 28 2.3 Asphalt, Bitumen and Tar 29 2.3.1 Asphalt 29 2.3.1.1 Forms of Asphalt 29 2.3.2 Bitumen 29 2.3.3 Tar 30 2.4 Lime 30 2.4.1 Properties of Lime 30 2.4.2 Types of Lime 30 2.4.3 Uses of Lime in Construction 31 2.5 Soil 31 2.5.1 Types of Soil 31 2.6 Sand 32 2.6.1 Types of Sand 32 2.6.2 Properties of Good Sand 32 2.6.3 Uses of Sand 32 2.7 Coarse Aggregates 33 2.7.1 Classification Based on Size 33 2.7.2 Classification Based on Shape 33 2.7.3 Classification Based on Texture 33 2.7.4 Classification Based on Origin 33 2.7.5 Classification Based on Density 33 Unit summary 34 Exercises 36 Practical 39 Know more 45 References and suggested readings 45 Interesting Facts 45 Unit 3: Artificial Construction Materials 47-79 Unit specifics 47 Rationale 48 Pre-requisites 48 Unit outcomes 48 3.1 Bricks 49 3.1.1 Constituents of Good Brick Earth 49 3.1.2 Conventional/Traditional Bricks 49 3.1.3 Modular/Standard Bricks 50 3.1.4 Special Bricks 50 3.1.5 Characteristics of a Good Brick 50 (xvi)  3.1.6 Field Tests on Bricks 51 3.1.7 Aerated Concrete Blocks 51 3.1.7.1 Advantages of Aerated Concrete Blocks 51 3.1.7.2 Limitation of Aerated Concrete Blocks 52 3.1.7.3 Comparison of Bricks and Aerated Concrete Blocks 52 3.1.8 Classification of Bricks 52 3.1.8.1 First Class Bricks 52 3.1.8.2 Second Class Bricks 53 3.1.8.3 Third Class Bricks 53 3.1.8.4 Over burnt or Jhama Brick 53 3.1.8.5 Comparison of various types of burnt bricks 54 3.1.9 Manufacturing Process of Burnt Clay Bricks 54 3.1.9.1 Preparation of Clay 54 3.1.9.2 Moulding of Bricks 55 3.1.9.3 Drying 55 3.1.9.4 Burning 56 3.2 Tiles 56 3.2.1 Flooring Tiles 57 3.2.2 Types of Flooring Tiles 57 3.3 Cement 58 3.3.1 Manufacturing of Cement 58 3.3.2 Types of Cement and Their Uses 61 3.3.3 Field Tests on Cement 62 3.4 Concrete Blocks 62 3.4.1 Advantages of Precast Concrete Blocks 63 3.4.2 Types of Precast Concrete Blocks 63 3.4.3 Uses of Precast Concrete Blocks 64 3.5 Plywood and Allied Products 64 3.5.1 Veneers and its Uses 64 3.5.2 Plywood 64 3.5.3 Particle Board 65 3.5.4 Laminated Board 65 3.6 Glass 65 3.6.1 Properties of Glass 65 3.6.2 Types of Glass 65 3.7 Ferrous and Non Ferrous 66 3.7.1 Ferrous Metals and Their Uses 66 3.7.2 Non Ferrous Metals and Their Uses 67 Unit summary 67 Exercises 69 (xvii)  Practical 72 Know more 79 References and suggested readings 79 Unit 4: Special Construction Materials 80-96 Unit specifics 80 Rationale 81 Pre-requisites 81 Unit outcomes 81 4.1 Introduction to Special Construction Materials 82 4.1.1 Water Proofing Material 82 4.1.2 Termite Proofing 82 4.1.2.1 Types of Termites 83 4.1.2.2 Principles of Termite Proofing 83 4.1.2.3 Stages of Termite Proofing 83 4.1.2.3.1 Pre-Construction Treatment 83 4.1.2.3.2 Post Construction Treatment 84 4.1.2.4 Chemicals used as Anti-termite Solutions 84 4.1.3 Thermal Insulating Materials 84 4.1.3.1 Characteristics of Good Thermal Insulating Material 85 4.1.3.2 Common Thermal Insulation Materials 85 4.1.4 Sound Proofing Materials 86 4.1.4.1 Characteristics of Good Sound Proofing Material 86 4.1.4.2 Common Sound Proofing Material 86 4.2 Fibres 87 4.2.1 Types of Fibres 88 4.2.2 Jute Fibres 88 4.2.3 Glass Fibres 88 4.2.4 Plastic Fibres 88 4.3 Geopolymer Cement 89 4.3.1 Constituents of Geopolymer Cement 89 4.3.2 Properties of Geopolymer Concrete 89 4.3.3 Uses of Geopolymer Concrete 89 Unit summary 90 Exercises 91 Practicals 94 Know more 95 References and suggested readings 96 (xviii) Unit 5: Processed Construction Materials 97-119 Unit specifics 97 Rationale 98 Pre-requisites 98 Unit outcomes 98 5.1 Plaster of Paris (POP) 99 5.1.1 Properties of Plaster of Paris 99 5.1.2 Types of Plaster of Paris 99 5.1.3 Uses of Plaster of Paris 99 5.2 Paints 100 5.2.1 Constituents of Paint 100 5.2.2 Function of a Paint 100 5.2.3 Characteristics of a Good Paint 100 5.2.4 Types of Paints 101 5.2.5 Cement Paint 102 5.2.6 White Wash 102 5.2.7 Varnish 102 5.2.7.1 Objectives of Varnishing 103 5.3 Industrial Waste Materials 103 5.3.1 Flyash 103 5.3.1.1 Advantages of Using Flyash 103 5.3.1.2 Uses of Flyash in Construction 104 5.3.2 Blast Furnace Slag 104 5.3.2.1 Advantages of Blast Furnace Slag 104 5.3.2.2 Use of Blast Furnace Slag 105 5.3.3 Granite and Marble Polishing Waste 105 5.3.3.1 Advantages of Granite and Marble Waste 105 5.3.3.2 Uses of Granite and Marble Waste 106 5.4 Agro Waste Materials 106 5.4.1 Rice Husk 106 5.4.2 Coir Fibres 106 5.4.3 Bagasse 107 5.5 Special Processed Construction Materials 107 5.5.1 Geo-Synthetics 107 5.5.1.1 Types of Geo-Synthetics 107 5.5.1.2 Functions of Geo-synthetics 108 5.5.2 Ferrocrete 108 5.5.2.1 Properties of Ferrocrete 109 5.5.2.2 Advantages of Ferrocrete 109 5.5.2.3 Disadvantages of Ferrocrete 109 5.5.3 Artificial Timber 109 (xix)  5.5.3.1 Properties of Artificial Timber 109 5.5.3.2 Advantages of Artificial Timber 110 5.5.4 Artificial Sand 110 5.5.4.1 Advantages of Artificial Sand 110 5.5.4.2 Artificial Sand versus Natural Sand 110 Unit summary 111 Exercises 112 Practicals 115 Know more 117 References and suggested readings 119 References for Further Learning 120 CO and PO Attainment Table 121 Index 122-124 (xx) d 1 Overview of Construction Materials UNIT SPECIFICS This unit has discussed the following aspects: Knowing about various construction materials. Classification of construction materials. Applications of building materials in different fields of construction like Transportation Engineering, Environmental Engineering, Building Structures, Irrigation Engineering; Identification of construction materials in their application. The practical aspects also taken into consideration to identify various available construction materials in laboratory on the basis of their sources are discussed in this chapter with the aim to generate creativity and curiosity amongst students. Besides a number of multiple choice questions, one word answer-questions, short and long answer type questions are given following bloom’s taxonomy at the end of the unit. Assignments may be framed using these questions by teachers. A list of references and suggested readings are stated in the unit for gaining more knowledge on construction materials. Further, it is noteworthy here that some QR codes have been given in the unit which can be scanned for getting deeper knowledge on the topic. After discussion of practical in identification of various construction materials, there is a ‘Know more’ section. This section has been prepared with great care to provide supplemental information on building construction materials for better understanding of the chapter. RATIONALE This introductory unit on construction materials helps the students to get primary knowledge about various construction materials available on the earth either naturally or as man-made. It discusses the classification of varied types of building construction materials in the basis of various parameters. 2 | Construction Materials and Testing Understanding of classifications is important for a civil graduate to select a proper material for a specified application. The use of construction materials is not limited to any one field of infrastructure but it goes into their applications in housing projects, industrial projects, irrigation structures, reservoirs, transportation sector, treatment plants for water and waste water etc,.. The selection of proper materials for a specific purpose is very important in construction industry to ensure cost effective and efficient structure which can serve the purpose for which it is constructed. Further, due importance must be given to the effect of chosen construction materials on environment. As most of the construction materials presently being used, are causing one or the other harmful effect on environment one needs to look for some sustainable alternate construction materials which are eco-friendly. This unit reinforces the basic knowledge on construction materials and helps in identifying right construction materials for the given project in an eco-friendly and economical way. PRE-REQUISITES Nil UNIT OUTCOMES List of outcomes of this unit is as follows: U1-O1: Understand the scope of construction materials U1-O2: Classify construction materials U1-O3: Select appropriate materials in different fields of construction U1-O4: Select construction materials on the basis of strength and durability U1-O5: Selection of construction materials on the basis of economy and sustainability EXPECTED MAPPING WITH COURSE OUTCOMES Unit-1 (1-Weak Correlation; 2-Medium correlation; 3-Strong Correlation) Outcomes CO-1 CO-2 CO-3 CO-4 CO-5 U1-O1 1 3 2 1 1 U1-O2 3 3 2 3 1 U1-O3 3 3 2 3 1 U1-O4 3 2 2 3 2 U1-O5 3 1 1 1 3  Construction Materials and Testing | 3 1.1 Scope of Construction Materials Construction materials are important for construction of new infrastructures of any kind. The scope of construction materials includes, but not restricted to, use of construction materials in building structures, transportation sector i.e. highways, railways and airways, irrigation structure, hydraulic structures, treatment plants etc. Besides, new construction, construction materials are of great importance for maintenance and repair work of infrastructure. High rise building, chimneys, silos, bridges, flyovers, dams, weir, warehouses, tunnels, pavements, railway tracks, water retaining structures, piers, embankments, sewers, treatment plants are few examples of high order construction projects. Each construction project is constructed to serve a specific purpose i.e. its serviceability and to serve for a specific life span i.e. its durability ‘Selection of right construction materials for the right project’ defines the expertise of an engineer. 1.1.1 Construction Material in Building Construction The most common use of construction materials is in building construction. Building construction includes small houses to high rise buildings, residential to commercial spaces, hospitals, academic institutions, hotels to restaurants, cinema halls to amusement parks, industry to public buildings. Building construction is not limited to construction of only new structures, rather, repairs and maintenance during the service life span of a structure by construction materials is also very important. Some of commonly used construction materials for building construction are – Cement, Reinforcement (Steel bars), bricks, mortar, timber, stones, polymer, ceramics, glass, rammed earth. 1.1.2 Construction Material in Transportation Engineering Transportation engineering includes means of commuting for people and goods. Highways, Railways and Airways are three major types of projects built under Transportation Engineering. Transportation engineering has a great impact on the countries’ economy. In fact, a country is known by the infrastructure and transport facilities it holds. A wide range of materials are used in construction of pavements and roads. Those include soils (natural or processed), aggregates (fine or coarse – natural or processed), binders like bituminous materials, lime or cement and certain admixtures targeted to achieve some specific property at site or to improve overall performance of the roads under traffic. The basic component of the foundation sub-grade or even road is soil as all the loads from any type of construction or traffic ultimately transmit on soil. Stone aggregates, also called mineral aggregates, are used as sub-bases, granular bases in bituminous roads (flexible pavements) as well as in cement concrete pavements (rigid pavements). Use of aggregates makes the pavement relatively cheaper. A highway engineer needs to give top priority to selection of appropriate type of aggregates giving due emphasis on their properties and characteristics. The use of bitumen in paving roads is well known to all but it picked up only in nineteenth century. Bitumen is an organic compound which is either taken directly from nature or can be obtained during the distillation of petroleum. The residue to refining industry for crude oil is bitumen and it provides superior riding surface. Another binder used in pavement is cement concrete which provides more durable pavements but are costlier than bituminous ones. 4 | Construction Materials and Testing 1.1.3 Construction Material in Environmental Engineering The biggest challenge faced due to the use of construction materials is their impact on environment. Impact includes challenges related to conservation of natural resources being exhausted, pollutants being produced in the processes of manufacturing and usage of construction material and disposal of waste materials produced at construction sites. The development of a sustainable environment and durable infrastructure is desired in the modern times of advanced technology. The construction materials used in various projects are exposed to a wide range of environmental conditions and hence it is important to study the effect of environment on various construction materials. The study of construction materials for environment engineering projects, not only includes use of construction materials but also looks up for environmental protection and sustainable development. The most popular construction material, concrete is also not environmental friendly and an engineer should target to choose a suitable material which does not cause or has minimum harm to environment. Besides, water and wastewater treatment plants need to be built in residential as well as industrial projects. Construction materials used in building of these treatments plants and need to be assessed for their behaviour towards chemically active environment. 1.1.4 Construction Material in Irrigation Engineering Irrigation is the science of planning an efficient, economical and artificial water supply system to soil for raising crops. The basic components of an irrigation system consist of an intake structures, pumping systems, conveyance systems, distribution systems and drainage system. For ensuring a regular water supply for agriculture, water is stored in one or the other reservoir like dams, transported to fields through constructed channels like canals, distributed to fields through pipes/cluster, regulated using checks and structures like turnouts. All these structures are required to be constructed by material which can resist erosion due to high velocity water flow and also has minimal seepage loss. Lining to these structures protect the sides and bed of the structure. These can be constructed using various materials like compacted earth, cement concrete, bricks, stones/boulders or even plastics. Concrete is the most popular material for lining, however, it is the most expensive option. An engineer must select an appropriate non-erodible material for construction of water retaining and supply structures to ensure longevity and durability of the project. Besides, irrigation engineering, choice of construction material is equally significant for other hydraulic structures like water tanks, dams, weirs etc. 1.2 Selection of Materials In construction industry, selection of appropriate material for specific purpose is very important. In history, there are examples where failures have occurred due to poor material selection. If for a particular application, good tensile strength is required, then one must choose a material with sufficient tensile strength i.e. metals rather than brittle material like bricks or concrete. Similarly, for outdoor applications, materials should be chosen giving due importance to environmental factors. A right material at right place ensures the serviceability of the structures and also tends to increase the life span of the structure. As construction activities are very tedious - involves a lot of finances, energy and time, a minimum maintenance requiring structure with long life span is always desired. Therefore, material selection is of utmost importance for long term success of a construction project.  Construction Materials and Testing | 5 1.2.1 Factors Affecting Selection of Material A large number of factors need to be taken in to account for selection of appropriate material for construction purpose. These includes- Strength – The strength (compressive strength, tensile strength or flexural strength) required for a specific application is different and hence is the foremost property taken into consideration for selection of materials. It is worth noting here that concrete is strong in compression but weak in tension whereas, steel is strong in tension as well as compression. Durability – The span, for which a material will be able to serve the purpose for which it is intended, is defined as its durability. For material selection in construction industry, durability of material is an important parameter. The durability of a product is defined in terms of its properties like mechanical properties, chemical composition, electrical and thermal properties, flexibility, self weight etc. Eco-friendliness – Most of the artificial construction materials involves energy intensive activities in their production and produce harmful by product or gases which cause adverse effects on environment. Cement industry is one such example. The material selection must be based on the environmental effect of the chosen materials. Alternative construction material available in nature or which are eco-friendly needs to be promoted in today’s era when the condition of environment is alarming. Earthen construction with use of bamboo is an example of eco-friendly construction. Economy – As construction is a costly industry, the cost of material affects the overall cost of the project. The initial and the maintenance cost of the materials are taken in consideration for selection of appropriate material. Besides these factors, many other parameters like aesthetic beauty of the material (especially for outdoor projects desiring natural looks), availability of the material and ease of using, affect selection of material. The actual performance of different materials under different loading and environmental conditions as available in historical examples must also be considered while doing material selection for construction activities. 1.2.2 Selection Materials on the Basis of Strength The strength of a material is the foremost property for its selection. Strength of a material refers to its ability to resist applied loads or force and to retain its original shape and size. Strength of a material depends on its mechanical properties like- Elasticity – It is the ability of a material to regain its shape and size on removal of stresses/forces applied on it. Plasticity – It is the ability of being moulded into desired shape. Ductility – It is the ability of a material to change its shape, like drawing into wires or threads, without losing strength or without breaking. Brittleness – The material which is hard but is liable to break easily is called brittle. Malleability – It is the ability to be shaped into thin sheets by hammering or forging. Toughness – It is the resistance of a material to be broken into two pieces by a crack, called fracture running across it. 6 | Construction Materials and Testing Hardness – The ability of a material to resist deformation or indentation on its surface is called hardness. The combined performance of a material on these parameters defines the strength of a material. The strength of a material is accessed in following types- Tensile Strength – The ability of materials to resist breaking under tension (length wise pull stress) is called its tensile strength. Compressive Strength – The resistance of a material to breaking under compressive forces (loads tending to reduce size) is called its compressive strength. Shearing Strength – The resistance of a material to with stand shearing load i.e. the forces that tend to produce sliding failure of a material along a plane that is parallel to the direction of force is called shearing strength. It is worth noting here that steel is a material which has good compressive as well as tensile strength. However, concrete is strong against compressive forces but weak under tensile loading. 1.2.3 Selection of Materials on the Basis of Durability Durability of a material refers to remain serviceable during the useful life span without damage or unexpected maintenance. The long term performance of a material is generally accepted depending on the previous experience of designer for that material. Sometimes, re-usable property of a material is also considered under its durability. As construction projects extensity involve huge money, time and energy, durability of construction materials becomes very important. Concrete, stone and steel are considered superior to timber, glass and bricks in terms of durability or service life for their structures. 1.2.4 Selection of Materials on their Eco-Friendly Nature The eco-friendliness of a construction material is defined as its ability to ensure optimal use of natural resources, produce minimum waste and ensure safety towards people and protection of environment. Further, an eco-friendly material is reusable or recyclable and durable. Some of the common eco- friendly construction material includes – Earth (soil), Bamboo, Recycled Steel, Fibres etc. However, the most popular construction material, concrete is not eco-friendly as the production of one the basic material of concrete i.e. cement is an energy extensive process which required huge fuels and also produce large amount of heat and green house gases. Also concrete is non –reusable material. The use of many waste materials like fly ash, slag, recycled aggregates, demolition wastes, industrial waste like metakaolin etc. in concrete are being tried to make concrete a greener material. 1.2.5 Selection of Materials on Basis of Economy The cost of a material is calculated in terms of its initial cost, handling cost, maintenance cost and re- sale cost. The construction material should be selected considering cost of a material, as more than 50% of the cost of an infrastructure project is its materials. Conventional concrete is a costly material but use of waste materials in concrete can make it economical to some extent. Steel as construction material has higher initial cost but its maintenance cost is less. Bamboo is economical than timber. Brick masonry structures are cheaper in their overall cost than stone masonry but the durability of stone masonry structure is more than brick masonry ones. Recently, some portion of low cost  Construction Materials and Testing | 7 materials and wastes are being mixed in an appropriate proportion to make cement concrete keeping in view economic and sustainability aspects. A civil engineer must consider all these factors for choice of right construction material for right purpose in a specified project. No construction project is made by a single construction material. Varied construction materials are selected for specific purpose in a construction project. For example – Concrete is used in flexural and compression structural members like beam, slabs, columns, foundation etc. Steel bars are used in these members as reinforcement to bear tensile and additional compressive strength. Steel is popular material in construction due to its versatility, sustainability and flexibility. Non load bearing member like walls, facia, parapets are made up of brick masonry. Metal is used in framing and roofing. Stone masonry is commonly used for exterior walls and fire places. Timbers and glass are used to make doors and windows considering ventilation and sunlight 1.3 Classification of Materials A broad classification of construction materials is as follows- Natural Materials Artificial Material Special Construction Material Finishing Materials Recycled Materials 1.3.1 Natural Building Materials The materials that are present naturally in environment and can be used for construction purpose are called natural building materials. Some of the examples of natural materials are sand, clay, gravels, rocks and metals etc. Sand is present naturally on the beds of the river. Rocks are naturally present big boulders. Stones in different sizes are obtained from quarry or through rock blasting. 1.3.1.1 Rocks Rocks are big boulders that are formed naturally at the crust of the earth. Many historical ancient structures are constructed with rocks e.g. Egyptian Pyramids. Rocks are strong in compression and can support large loads. Mortar is used to hold rocks together. 1.3.1.2 Clay Clay and mud are natural construction materials which are popular even in modern construction. Clay has a high thermal mass which helps it to keep cool during the summers and warm in winters. A constant temperature can be maintained in clayed structures. It reduces the energy consumption of the building in running air conditioners and heaters. 1.3.1.3 Sand Sand is formed at the river bed by decomposition of sandstone due to weathering action; Sand is used as a filling material in concrete and is responsible for volume increase in the mix, making it compact and economical. 8 | Construction Materials and Testing 1.3.1.4 Timber Wood used for engineering purpose is called timber. In building construction, timber is used to make doors, windows and furniture. Besides, timber is used as material for shuttering and framework in reinforced concrete structures. Sometimes it is used as roofing and flooring material also. 1.3.2 Artificial Building Materials The man made materials which are used for various construction purposes are called Artificial Building Materials. Concrete, bricks, steel, glass, artificial sand, plastics are some of the popular artificial materials used in construction. 1.3.2.1 Concrete Concrete is the most popular and versatile building material. Concrete is a mixture of cement, sand, aggregates in wet state. Concrete has good compressive strength, but it is weak in tension. Steel bars are provided in concrete to take care of the tensile stresses and it is called Reinforced Cement Concrete (RCC). Concrete is used in construction of structural members like beams, slabs, columns and foundation in buildings. 1.3.2.2 Bricks The second most popular artificial building material is brick. It is widely in construction of walls. Bricks are composed of mainly clay involving the process of burning at very high temperature in kiln. Bricks have good compressive strength. Bricks are available in market in standard sizes and varied colours and hence are used for desired appearance of the structure. 1.3.2.3 Steel Steel is used in many forms in construction activities. These include reinforcing bars, trusses, angle- sections etc. Steel has good compressive as well as tensile strength. Some treatments are carried out on steel to make it resistant to corrosion. Steel has good tensile strength and durability. 1.3.2.4 Glass Glass is a non crystalline amorphous material. It is used in construction where sunlight is required. Window panels are mostly provided with glass. Glass in toughened form is also used for partition walls and decorative looks to enhance the aesthetic appearance of the building. 1.3.2.5 Artificial Sand Artificial sand, also known as manufactured sand, is made by mechanical cursing of stones. The use of artificial sand is increasing day by day as there is a shortage of river sand. Artificial sand is used in mortar and concrete. 1.3.2.6 Plastic Plastics is used in construction in the form of sheets and pipes etc. Plastic is an economical alternative and is easy to handle.  Construction Materials and Testing | 9 1.3.3 Special Construction Materials The construction materials which are manufactured specially to possess some special desired properties and are used for specific purposes fall under this category. These include Poly-Vinyl Chloride (PVC) materials, Polypropylene fibbers (PPF), Emulsion and paints etc. 1.3.3.1 Poly-Vinyl Chloride (PVC) PVC is an economical construction material which has very good insulating properties, good water resistance and good fire resistance. PVC sheets are used to make electrical panels and boards in buildings. It is a light weight material and is easy to use and assemble. PVC pipes are used as water and waste water carrying pipes. PVC sheets are used as flooring, roofing and wall panelling to give decorative look to the structure. 1.3.3.2 Polypropylene Fibres (PPF) A polypropylene fibre has good compressive and tensile strength. These are used in reinforced concrete as a partial replacement to steel to take up tensile stresses. 1.3.3.3 Emulsions and Paints Paints of various types are available in the market. Emulsions are oil based paints which are prepared by dispersion of bitumen in water in presence of some stabilizers like oleic acid. Emulsions provide a smooth water proof coating which ensure a good finish also. Bitumen is provided as a coating at Damp Proof Coarse (DPC) level in the building. 1.3.4 Finishing Materials The construction materials which are used to provide a smooth finish on the surfaces are called finishing materials. Finishing materials includes lime plaster and Plaster of Paris (POP) etc. 1.3.4.1 Lime Plaster The surfaces of brick walls are covered with a layer of lime plaster to act as a smooth surface. Lime mortar is prepared by mixing sand and lime in equal proportions. Lime plaster has a good binding property to brick masonry and concrete. 1.3.4.2 Plaster of Paris (POP) Gypsum when heated upto a certain temperature results in a fine powder which is called Plaster of Paris. During heating the water of crystallization gets removed from gypsum. Plaster of Paris is a popular material of plastering. POP sets immediately when water is added to it. This form of plaster is used for interior architectural works as sharp edges and corners can be achieved using POP. 1.3.5 Recycled Materials The waste materials from various industries, agriculture and even waste from demolished structures are used as recycled materials in construction. These include fly Ash (a waste from thermal power plants), timber creek, agricultural by-products like bagasse, stubble, recycled aggregates etc. Timber creek is prepared by blending saw mill dust, sand, cement and some binder. It can be moulded to prepare blocks, bricks, cubes etc. Fly ash has excellent cementitious properties and can be used as partial replacement to cement and sand. Agricultural wastes by products are added as supplement material to concrete to 10 | Construction Materials and Testing act as mineral admixture to enhance its properties. Recycled aggregates are generally used as a filler material under flooring. All recycled materials are used in construction have an advantage of economy and energy. UNIT SUMMARY Sectors for use of Construction Material o Building Construction o Transportation Engineering o Environmental Engineering o Irrigation and Water Resources Engineering Properties desired in Construction Materials o Strength o Durability o Serviceability o Pleasing look (Appearance) Factors affecting selection of Building Construction Materials o Load Carrying Capacity (Strength) o Cost o Eco-Friendliness o Life Span (Durability) o Ease of Availability o Appearance Classification of Construction Materials o Natural Materials e.g. Stone, Sand, Clay o Artificial Materials e.g. Concrete, Brick, Glass o Special Materials e.g. PVC, PPF o Finishing Materials e.g. Lime Plaster, POP o Recycled Materials e.g. Timber Creek, Recycled Aggregates Commonly used Construction Materials for Buildings o Mud and Clay o Bricks and Blocks o Sand o Aggregate o Stone o Concrete o Timber o Steel EXERCISES Multiple Choice Questions 1. Stones from natural rocks are taken out by- a. Quarrying b. Weathering c. Dressing  Construction Materials and Testing | 11 d. Cladding 2. Which of the following is natural construction material? a. Concrete b. Sand c. Cement d. Glass 3. The resistance to fail by sliding is called a. Compressive Strength b. Tensile Strength c. Shearing Strength d. None of the above 4. The property to regain shape and size on removal of load is called a. Elasticity b. Plasticity c. Hardness d. Toughness 5. Which material is preferred for making fireplaces? a. Bricks b. Stones c. Concrete d. Timber 6. Match the name of stone with its application Name of Stone Application a. Granite 1. Flooring b. Lime Stone 2. Ornamental Work c. Marble 3. Sea Walls d. Slate 4. Cement Manufacturing 7. Which material keeps the structure cool in summers and warm in winters? a. Timber b. Bricks c. Bamboo d. Clay 8. Which of the following is most eco-friendly construction material? a. Steel b. Concrete c. Mud d. Glass 9. Concrete is strong in a. Compression b. Tensile c. Shear d. None of the above 10. Bitumen is a by-product of which industry a. Paper b. Chemical 12 | Construction Materials and Testing c. Fertilizer d. Distillery 11. Which of the following is an organic building material? a. Lime b. Wood c. Gypsum d. Mud 12. Which material is used for external plastering works? a. Lime Plaster b. Plaster of Paris c. Mortar d. None of the above 13. Which material out of the following is used for form work and shuttering? a. Concrete b. Bricks c. Stones d. Timber 14. Which of the following is an artificial building material? a. Wood b. Rocks c. Sand d. Concrete 15. Polypropylene fibres belong to which category of construction material a. Natural b. Special c. Finishing d. Recycled 16. Which of the following is used to make partition walls? a. Bricks b. Stones c. Glass d. Clay 17. Emulsion paints are used to provide a. Smooth Finish b. Decorative Finish c. Water Proof Coating d. All of the above 18. The by-product of thermal power plants is a. Fly Ash b. Bagasse c. Sludge d. Metakaolin 19. POP is used for finishing of a. External Surface  Construction Materials and Testing | 13 b. Internal Surface c. Vertical Surface d. All of the above 20. Steel is strong in a. Compression b. Tension c. Both d. None of the above Answers of Multiple Choice Questions 1 (a), 2 (b), 3 (c), 4 (a), 5 (b), 6 (a-3, b-4, c-2, d-1), 7 (d), 8 (c), 9 (a), 10 (d), 11 (b), 12 (a), 13 (d), 14 (d), 15 (b), 16 (c), 17 (d), 18 (a), 19 (b), 20 (c) Short Answer Type Questions (1.1-1.10) and Long Answer Type Questions (1.11-1.15) 1.1 Discuss the scope of construction materials. 1.2 List of construction materials used in transportation engineering. 1.3 What are various types of construction material? 1.4 State the desired properties for a construction material. 1.5 Define serviceability. 1.6 Give some examples of natural construction materials. 1.7 State some applications of construction material in irrigation engineering. 1.8 Name any four artificial construction materials. 1.9 What are various types of strength considered for selection of a building material? 1.10 Write a short note on flyash. 1.11 Explain the use of construction material in varied sectors of Civil Engineering. 1.12 Classify construction materialson the basis of their existence. 1.13 What are the factors considered for selection of construction materials? Explain. 1.14 Why is selection of appropriate construction material important for a construction project? 1.15 Write an explanatory note on finishing construction materials. PRACTICAL Aim Identify the available construction materials in the laboratory on the basis of their sources. Materials Required Sample of various construction materials 14 | Construction Materials and Testing Theory The construction materials can be identified and classified on the basis of their source of availability. The data for some of the common construction materials is as follows- Material Source Category Brick Made in Kiln Artificial Clay Natural Occurring in Soil Natural Mud Natural Occurring in Soil Natural Timber Exacted from Trees Natural Steel Furnace Artificial Stone Blasting of Rocks Natural Glass Made in factories Artificial Concrete Mixture of Cement, Sand, Aggregate and Water Artificial POP Heating of Gypsum Finishing Lime Plaster Mixture of Lime and Sand Finishing Procedure 1. Collect the sample of available construction materials. 2. Arrange the construction materials on table. 3. Observe the construction materials closely to know their source. 4. Record the observations carefully. Observations Sr. No. Material Name Source 01. M1 02. M2 03. M3 04. M4 05. M5 Result The given material belongs to following categories Category Sr. No. Material Name (Natural/Artificial/Recycled/Special/ Finishing) 01. M1 02. M2 03. M3 04. M4 05. M5  Construction Materials and Testing | 15 Conclusion The given construction materials can be identified and classified on the basis of their source of availability. Precautious 1. The given material should be in original shape and size. 2. Any additional covering on the material sample should be removed before observing it. 3. Minimum of three samples of a material should be observed KNOW MORE The use of construction materials is as old as time immemorial. Building materials are the most important component of an infrastructure project as it involves huge cost and affects the life of a project directly. History is available for building construction materials for some thousands of years. Housing and shelter have always been on priority of human demands. Initially, temporary structures made up of leaves, tree stem, branches, straw, bushes were used as houses. Later came the era of stones, clay, mud and timber. The biggest advantage of these products was that these materials were available in abundance in nature. Mud and clay were popular because of their ease of moulding and could be held together using straw, sticks and other natural products like cattle dung. Wood was other common construction material because of its strength and ease to handle. Later there was a demand for permanent structures. Civilization shifted from tents and huts to permanent houses made up of cement, concrete, steel and bricks. The invent of these construction materials brought a revolution in construction industry as these materials were superior in terms of their strength, durability and serviceability. The use of these artificial construction materials are energy extensive and involves huge construction cost. Hence, the selection of proper building material has great significance. The growth of a country is developed by the kind of infrastructure it has. The modern construction has shifted from single-one-storey houses to skyscrapers and high rise buildings. These projects involve use of many more special construction materials like glass, steel, metals, PVC, PPFs etc. As the rising index of construction activities is putting a lot of stress on environment by depletion of natural resources on one side and release of harmful pollutants and waste generation on other side, there is a need to look for alternative construction materials. The research and trial activities on use of recycled products as construction materials can be a successful solution to solve the present problems of construction materials. Many successful examples of the same are available in the history. REFERENCES AND SUGGESTED READINGS Varghese, P.C., Building Materials, PHI learning, New Delhi. Rangwala, S.C., Engineering Materials, Charator Publisher, Ahemdabad. 16 | Construction Materials and Testing Some Inquisitive examples 01. English Channel Tunnel (1994) – The English Channel Tunnel connects the shore of Kent in UK with Pas-De-Calais in France. It is designed to carry high speed passenger train, road vehicles and international goods trains at a depth of 115m below sea level at its deepest point. It is one of the highest value engineering projects. 02. Brooklyn Bridge (1883) – It is one of the oldest bridges in United States. It is steel wire suspension bridge build with a cost of $15.5 million. It is a historic icon for New York City. 03. Great Pyramid of Giza - It is one of the seven wonders of ancient world. It was tallest structure in the world for over 3800 years. It is estimated that 5.5 million tonnes of lime stone, 5 lacs tonnes of mortar and 8 thousand tonnes of granite costing $5 billion were used in its construction. 04. Bandra Worli Sea link, Mumbai – It is an eight lane cable stayed bridge constructed in Arabian Sea to join two suburbs of Mumbai. It is an engineering marvel and an architectural wonder. 05. Burj Khalifa, Dubai (2010) – The tallest structure in the world, Burj Kalifa is the most iconic building. Its construction started in 2004 and was completed in 2010. It is 828 m tall with 163 floors and having highest outdoor observatory deck. An estimated amount of 3 lacs cubic meter of concrete and 39 thousand tonnes of steel were used in its construction. The total aluminium used on Burj Kalifa is equivalent to five A380 aircrafts. It involves a world record of installation of glass façade at the height of 512 meters. It includes more than 380 skilled civil engineers in its construction.  Construction Materials and Testing | 17 2 d Natural Construction Materials UNIT SPECIFICS This unit discusses the following aspects: Knowing various natural construction materials. Understanding the use of specific natural construction materials in construction. Detailed classification of various natural construction materials. Knowing various methods adopted to work with specific natural materials. Understanding the use of tools for natural construction materials. Various experimentation procedures on natural construction materials are also explained in the unit to enhance the knowledge of students on the use of construction materials in an appropriate form. Some examples from history have been quoted in this chapter to create an inquisitive thought amongst the users about available natural construction materials. The additional list of suggested readings and references is given at the end of the unit to satisfy curiosity on the topic. This chapter imparts the knowledge on characteristics and use of natural construction materials like stones, timber, bituminous materials, lime, soil, sand and aggregates. At the end of the unit, several multiple choice questions, short answer type questions and long answer type questions have been stated to assess the knowledge gained by the users. The framework blooms taxonomy i.e., remember, understand, apply, analysis and create have been kept in mind while making the questions. Assignment and quizzes can be framed using these questions. Further, many QR codes, provided throughout the unit, can be scanned to get deeper knowledge on the topic and to create interest on the subject. The section named ‘Know more’ acts as an icing on the cake and provides supplementary information on the characteristics and uses of natural construction materials. The unit summary at the end of the chapter gives a quick revision on ‘what we have learnt’ and generates creative and inquisitive nature among the students. RATIONALE This unit on natural construction materials helps students understand which materials are available naturally in our surroundings that could be used in the construction. It further imparts knowledge on the use of every natural construction material for the specific purposes. Besides, 18 | Construction Materials and Testing the characteristics desired for good natural construction material have been stated in the unit to help user select an appropriate material for a specific purpose at the site for a project. General properties, types and use of various natural construction materials give a comprehensive knowledge to the students on the topic. The unit further specifies the advantages and limitations on the use of various natural construction materials. Understanding the benefits available and the challenges faced in use of each natural construction material, ensures effective and efficient selection of construction materials. The use of natural construction materials has been popular since pre-history times but, at present, there are popular arguments on suppressing the use of natural construction materials and looking for alternative materials for construction. The advantages of natural construction materials make construction industry inclined towards their usage and at the same time their limitations provoke the industry to look for alternatives. A rationale on the use of natural construction materials can be sought by civil engineers after understanding this chapter thoroughly. PRE-REQUISITES Basic knowledge on construction materials (i.e., Unit-I) UNIT OUTCOMES Following is the list of outcomes from unit on Natural Construction Materials: U2-O1: Define and understand various natural construction materials. U2-O2: Understand the desired properties of natural construction materials. U2-O3: Understand the types of various natural construction materials. U2-O4: Know the uses of each natural construction materials. U2-O5: Apply the knowledge gained to select appropriate natural construction material for a specific purpose. EXPECTED MAPPING WITH COURSE OUTCOMES Unit-2 (1-Weak Correlation; 2-Medium Correlation; 3-Strong Correlation) Outcomes CO-1 CO-2 CO-3 CO-4 CO-5 U2-O1 3 3 1 2 2 U2-O2 2 3 1 1 1 U2-O3 2 3 1 2 1 U2-O4 3 3 1 2 1 U2-O5 3 3 1 3 1  Construction Materials and Testing | 19 2.1 Building Stones Stones are considered as one of the popular building material due to their easy availability in nature from rocks. The earth’s crust is made up of rocks. Rocks are nothing but mineral mass, having more or less homogeneous uniform composition. Natural rocks are the main source for getting building stones and also for producing mineral binding materials like lime, gypsum and cement by certain processes. Building stones have the advantage of good strength and durability. In older days construction, many examples of structures like temples, dams, retaining walls, abutments, monuments etc. are made up of stones. 2.1.1 Good Building Stone Stones are used in varied construction projects. Different civil engineering projects require several types of stone. Hence, it is important to check the suitability of a particular type of stone for a specific project which is having different loading and environmental conditions. However, some of the typical characteristics on which the quality of stone depends are discussed as below – 1. Appearance – Building stones should have pleasing appearance and should be of uniform colour. This quality becomes more important where stones are to be used for decorative works and placed for aesthetic beauty of the structure. Light coloured stones are superior to dark coloured stones in terms of their resistance to weathering action. 2. Strength – Most types of stones have reasonably good compressive strength. Due to this reason, stones are mostly used as a compression member. Igneous rocks have a better strength as compared to sedimentary rocks. Metamorphic rocks also possess relatively good strength. 3. Weight – Stones should have less porosity and more compactness. This property gives high weight to stone and hence, stones have high compressive strength. 4. Hardness and Toughness – Hardness is resistance to scratching and toughness is resistance to breaking. Stones with good hardness and toughness have resistance to wear and tear, specially required for road projects. 5. Porosity and absorption – All stones have some porosity. However, porosity, in stones, is not a desirable property as absorption of rainwater by stones leads to their deterioration. Also, in cold climates, the freezing of absorbed water in stones may cause cracks in stones. 6. Compactness – Building stones should have good compactness as this property helps a stone to withstand the effects of external agencies effectively. 7. Grain Fineness – Stones with fine grained structure are easy to carve/dress and hence, are suitable for moulding. However, non-crystalline stones tend to disintegrate/break under the action of external natural agencies. 8. Fire Resistance – Stones must be fire resistant. Fire resistance means that the stone should be able to retain its shape and size on exposure to fire. Most of the stones can resist fire up to very high temperature; say of the order of 800°C. 9. Durability – Durability of stone refers to its longevity of life. Stones which have acid resistance and negligible water absorption are durable. Stones having compact and homogenous nature have better durability. 10. Dressing – The process of shaping of stones for some decorative purpose is called dressing. Soft stones like slates and limestone are easy to dress. Hard stones cannot be dressed easily. 20 | Construction Materials and Testing 2.1.2 Requirements of Good Building Stone i. A good stone should be free from soft patches, cracks, cavities and is of uniform colour and texture. This ensures good appearance of stone. ii. The building stone should be compact to ensure good strength and high density. iii. A good building stone should be hard, strong and durable. It should have good weather resistance, acidic resistance, fire resistance and negligible water absorption. iv. The stone should be easily and economically available in bulk. Most of the construction projects require huge quantities of stones and hence, the stones should be available near the project otherwise the cost of transportation of stones is going to be very high and can make the project uneconomical. v. The good stones should be easily workable so that it can be dressed/ moulded into desired shape. The following table gives the value for some of the desirable properties of good building stone – Table 2.1 – Desirable limits for Properties of Good Building Stone Property Desirable Limit Appearance Uniform Colour Strength >100N/mm2 Specific Gravity >2.70 Hardness i.e. wearing Resistance 800°C 2.1.3 Quarrying of Building Stones The process of taking out stones from rock beds is called quarrying and the places from where stone are extracted are known quarry. 2.1.3.1 Methods and Tools of Quarrying i. Digging – Digging is the simplest method to obtain stones and is applicable for soft rocks. Digging of soft rocks is carried out with the help of hand tools like chisels, hammers etc. ii. Heating – The exposed part of some rocks is separated from the main mass by heating process which is carried out by burning some fuels on the exposed surface of the rocks. Due to continuous heating for hours, there is an unequal expansion of the rock, and that part of the rock gets separated and stones are obtained from it.  Construction Materials and Testing | 21 iii. Wedging – There are some rocks which are soft and stratified i.e., these are formed in layers which can easily be split. Such rocks can be drawn to stones by wedging. The tools used for wedging are pickaxes and crow basis. Wedging is a simple method which is successfully used for quarrying of limestone, marbles and slates. iv. Blasting – Blasting is the most typical method of quarrying. It is used for hard and compact rocks. Blasting is carried out in various stages. Firstly, holes are drilled in rocks with the help of steel bars with sharp ends or by using drilling machine. Then, the drilled holes are filled carefully with suitable explosives. These explosives are then tempted to avoid blasting of explosives within the holes before firing. The fuse for firing is placed carefully and later fired. When the explosion takes place, the masses of stones all around the hole are removed and obtained. 2.1.4 Dressing of Stones The stones obtained from quarrying have a very rough surface and irregular shape. The process of finishing the stones to obtain a regular shape and smooth surface is called dressing of stones. Hard stones are difficult to dress. The benefits of dressing are a. Dressing results in good appearance and regular shape of stones. b. Dressed stones are easy to handle in terms of their transportation and usage. c. Dressing ensures proper bedding in stone masonry and suit building requirements. 2.1.4.1 Methods of Dressing of Stone i. Quarry Dressing – When the stone dressing operations are carried out at the quarry site itself, it is called quarry dressing. This helps in reducing the cost of transportation. ii. Site Dressing – When stones are shaped and surface finished at the site of usage, it is called site dressing. This method of dressing is preferred for more effective dressing of stones which ensures desired suitable size and surface finish. 2.1.5 Tools used for Dressing of Stones Dressing of stones involves use of many tools as shown in Fig.2.1. Now a days, mechanical tools are preferred over manual one to save time for dressing of stones. Some of the tools used include - Hammer – Hammer is the most commonly used tool for dressing of stones. Hammered dressed stones do not have any shape edges or irregular corners and hence, are well suited for masonry works. Some of the common types of hammers are Club Hammer, Spall Hammer, Mash Hammer and Wallers Hammer. Chisel – Chisels are sharp tools used to remove extra part of stone near their central mass. Chisel dressed stones are used in plinths and corners of the building by dressing in required shape and size. Gad – Gad is a metallic tool made up of iron, used to split the stones in pieces. Saw – Various types of saws are used to dress the stones by cutting process. Hand saw is used to cut soft stones. Cross-cut saw is used to cut hard stones. 22 | Construction Materials and Testing Pitching Tool – Pitching tool is used to get stones of required size by removing layers of masses from original stone. Square Set – It is a tool used to set edges at right angles for stones. Punching and Pointing Tool – Punch tool is used for rough dressing of soft stone whereas pointing tool is used to make holes or rough dressing in hard stones. Drafting Chisel – These are special purpose chisel used to dress the stones very finely. Drafting of stones refers to maintaining fine edges, cuts and shapes in stones.  Construction Materials and Testing | 23 Figure: 2.1- Tools for Dressing of Stones 2.2 Timber The wood which is suitable for construction and other engineering purposes is called Timber. In building construction, timber is used in doors, windows, partitions, shelves, furniture and railing etc. Generally, timber is obtained from two types of trees – Endogenous Trees – The trees which grow inwards e.g., bamboo and palms. These are found in tropics and have limited use in engineering. Exogenous Trees – The trees which grow outwards i.e., there stems get thicken with growth e.g. Teak, Babul, Sal etc. These are mainly used for engineering and building construction purpose. Timber is an expensive material and should be carefully selected for a specific purpose. Timber is most commonly used in the form of plywood or raw wood. Ply board is obtained by pressing together several layers of wooden sheets and ply board refers to board made up of agro waste, cellulose etc, blended with adhesives to give a solid board. Most popular woods for doors and windows include Teak, Sal and Deodar. Teak wood is considered superior over other wood for the advantage of its natural look, durability and long lasting characteristics. 2.2.1 Structure of Timber The structure of timber which is visible to naked eye is called its macro-structure. The cross-section of timber has ring like structures, called annular rings which can be counted to know the age of the tree. The structure of timber (Fig. 2.2) shows following parts - i. Pith – The inner most portion or core of the tree is called pith or medulla. It is very soft portion as compared to other parts of the tree. ii. Heart Wood – The annual rings around the pith form heart wood. The heart wood rings are closer to each other than the rings present in sap wood. Heartwood is darker in colour and consists of hard, strong and durable wood. Basically, heart wood is the dead portion the tree and does not participate in the growth of the tree. The sap wood gets converted into heart 24 | Construction Materials and Testing wood over a period of time of the order of 15-20 years. Heart wood is the best portion of a tree to be used for engineering purpose. iii. Sap Wood – The outer annual sings around the heart wood are known as sap wood. This portion is generally lighter in colour and weight than heart wood. Sap wood has a lot of moisture content and it participates actively in the growth of the tree. Sap wood is usually not used for construction purposes as it is liable to decay fast. iv. Cambium Layer – The thin layer of sap i.e., plant juice and moisture, present between sap wood and inner bark is known as cambium layer. This layer is nothing but immature sap wood. v. Inner Bark – The inner bark is a skinny layer around cambium layer which protects cambium layer from any injury and ensures supply of sap juice to other parts of the tree. vi. Outer Bark – The outer most protective layer or skin of a tree is called outer bark. Outer bark protects the tree from high temperature and any kind of mechanical harm. vii. Medullar Rays – The thin radial fibres which extend from pith to cambium layer are called medullary rays. The function of medullary rays is to hold the annual rings of sap wood and heart wood together and to supply the stored food to the parts of the tree according to the necessity. Figure: 2.2- Structure of Timber 2.2.2 General Properties of Good Timber A good timber should be strong, tough and durable. A good timber should possess following characteristics – i. Appearance – A good timber should have uniform and compact appearance. It should have straight fibres which are considered pleasing to sight and should have shiny appearance. ii. Colour – The timber is considered good, if it is dark in colour. Dark colour is taken as a symbol of good strength.  Construction Materials and Testing | 25 iii. Defect-Free – A good timber should be free from defects like knots, flaws, shakes etc. Also, a timber should have sweet smell and it should give good sound when struck to ensure that it is defect free. iv. Strength – A good timber should be strong enough to bear the loads applied to it. It should be strong against compressive loads as well as against loads applied in transverse direction. Timber with good strength is used as structural members like beam. Rafter, joist etc. v. Durability – A good timber should be durable against the attack by fungi, insects, chemicals etc. and should also be able to resist the action of physical and mechanical agencies. vi. Weather Resistance – A good timber should be capable of offering good resistance against weathering forces like alternate wetting and drying, alternate freezing and thawing (cooling and Heating) conditions, temperature variations, wind effects etc. vii. Fire Resistance – Most of the timber are generally not fire resistance. However, a good timber should have sufficient fire resistance i.e., it should not catch fire easily. A dense compact wood has better fire resistance. viii. Elasticity – Elasticity refers to the property of regaining original shape and size when loads are removed. A good timber should be capable of regaining its original shape without any permanent deformation when loads are removed. ix. Workable – A good timber should be easy to work with tools like saw, planning tools etc. and it should not clog the teeth of the saw. x. Toughness and Abrasion – A good timber should be able to resist shocks due to vibration. Also, it should not deteriorate due to mechanical wear i.e., due to rubbing action of the loads. 2.2.3 Seasoning of Timber The process of drying out the timber to reduce its moisture content to prevent it from possible decay or fermentation is called seasoning. As the fresh timber contains 30-50% of sap and water, it is liable to decay or bending even under normal environmental conditions of temperature variations. Hence, it is important to remove the sap and moisture from the timber and such processed are collectively called seasoning of timber. 2.2.3.1 Advantages of Seasoning Seasoning makes the timber strong and durable and increases its life span. The following advantages are achieved by seasoning of timber- i. Seasoning decreases the volume and weight of the timber and hence makes it easy to handle and transport. ii. Seasoning of timber improves the strength, hardness and toughness of the timber. iii. Seasoning results in reduced moisture content in timber and hence improves the resistance to decay due to attack by insects and fungi. iv. Seasoned timber is more workable as it has reduced tendency to bend, wrap or crack. v. Seasoning of timber renders it fit for decorative works like polishing, painting and varnishing etc. 2.2.3.2 Methods of Seasoning The methods of seasoning of timber are broadly classified into two categories- 26 | Construction Materials and Testing i. Natural Seasoning or Air Seasoning – Natural seasoning of timber is a simple, cheap and least care demanding process. In this method timber, in the form of logs or planks or post, is dried by direct action of air, water or sun. The timber logs are stacked in cross wise direction in alternate layers to ensure free circulation of air around them. This type of seasoning is very slow and takes few months to an year depending upon the kind of wood and its thickness. As there is no control on temperature and humidity in natural seasoning, the desired quality of seasoning is not attained. ii. Artificial Seasoning – Artificial seasoning, besides being a fast process, has the advantages of controlled temperature and humidity and hence, the timber can be dried under control conditions to attain desired moisture content level. The various methods used for artificial seasoning are – a. Kiln Seasoning – In this method, timber is stacked in a chamber in a kiln and hot air is freely circulated around it for 3-6 days. In this way, the timber is dried to desired moisture content level at a much faster rate under controlled conditions of temperature and humidity. Kiln seasoning is an expensive method requiring skilled supervisor, but it gives a well seasoned uniform timber. b. Chemical Seasoning – In this method, the timber is immersed in the solution of suitable salts like ammonium carbonate or urea which absorbs the moisture content from inside of the timber and then timber is left for air seasoning for exterior surface. This method takes 30-40 days. c. Electric Seasoning – In this method, high frequency currents are passed through the timber which helps in drying of sap and moisture. This method is the fastest method of seasoning and takes 5-8 hours only, however, it is a very costly method and not suited for large scale seasoning. d. Water Seasoning – In this method, logs of freshly felled trees are fully immersed in running stream of water for about 3-4 weeks. The thicker end of the log is aligned in upstream direction and hence, the sap of the timber is washed away by water. Then