1CHAPTER 1

INTRODUCTION

1.1 GENERAL

The constant developmental activities in civil engineering and

growing industrial activities have created a continuous demand for building

materials which satisfy all the stringent requirements regarding the short-term

and long-term performance of the structure. As the structures of tomorrow

become taller and more complex, the materials of construction will be

required to meet more demanding standards of performance than those in

force today (Fuller 2006).

Indias present housing shortage is estimated to be as high as 31

million according to census and out of these shortages 24 million units are in

rural areas and 7 million units in urban areas. Such a large housing

construction activities require a huge amount of money. Out of this total cost

of housing construction, building materials contribute to about 70% of cost in

developing countries like India. The increase in the popularity of using

environmental friendly, low-cost and light weight construction materials in

building industry has brought about the need to investigate how this can be

achieved by benefiting the environment as well as maintaining the material

requirements affirmed in the standards (Turgut Paki and Algin Halil Murat

2007).

2In the construction industry, building technology is heading towards an

entirely new era because of the usage of industrial wastes in various forms of

building material production. For instance, the use of waste rubber, glass powder,

industrial waste fibres, wood sawdust wastes and limestone powder wastes in

building material production has received diligent attention over the past few years.

This is quite understandable because it is slowly but increasingly being recognized

that the economic progress in construction depends more on an intelligent use of

materials and constant improvement of available materials.

1.2 INNOVATION OF PAPERCRETE

Papercrete is a material originally developed 80 years ago but it is

only recently rediscovered. Papercrete is a fibrous cementitious compound

comprising waste paper and Portland cement. These two components are

blended with water to create a paper cement pulp, which can then be poured

into a mould, allowed to dry and be utilized as a durable building material. It

should be noted that papercrete is a relatively new concept with limited scope.

Papercrete has three derivatives, namely fibrous concrete, padobe

and fidobe. The fibrous concrete is a mixture of paper, Portland cement and

water. There are no harmful by-products or excessive energy use in the

production of papercrete. Padobe has no Portland cement. It is a mix of paper,

water and earth with clay. Here clay is the binding material. Instead of using

the cement, earth is used in this type of brick. This earth should have clay

content of more than 30%. With regular brick, if the clay content is too high

the brick may crack while drying, but adding paper fiber to the earth mix

strengthens the drying block. It gives flexibility which helps to prevent

cracking. Fidobe is like padobe, but it may contain other fibrous material.

31.3 BRIEF HISTORY OF BRICKS

All over the world, bricks are the most widely used construction

materials for the construction of buildings. The bricks are obtained by

moulding clay in rectangular blocks of uniform size and then by drying and

burning the blocks. As the bricks are of uniform size, they can be properly

arranged. The common brick is one of the oldest building materials and it is

extensively used at present as a leading material in construction. In India, the

process of brick making has not changed since many centuries except in some

minor refinements. There has been hardly any effort in our country to

improve the brick-making process for enhancing the quality of bricks. Also

the structures in view of their compressive strength, structural stability and

relative low cost have not undergone any drastic change. But it has two major

drawbacks, namely self weight and brittleness.

1.4 PAPER

Paper is a natural polymer which consists of wood cellulose, which

is the most abundant organic compound in the planet. Cellulose is made of

units of monomer glucose (polysaccharide). The links in the cellulose chain

are a type of sugar as -D-glucose. Despite containing several hydroxyl

groups, cellulose is water insoluble. The reason is the stiffness of the chains

and hydrogen bonding between two OH groups on adjacent chains. The

chains pack regularly in places to form hard, stable crystalline regions that

give the bundled chains even more stability and strength. This hydrogen

bonding is the basis of papercretes strength. By applying a force on the paper

the hydrogen bond between the water and the cellulose molecule is broken.

Coating cellulose fibers with Portland cement creates a cement matrix, which

encases the fibers for extra strength to the mix. Cellulose hydrogen bonds are

shown in Figure 1.1.

4Figure 1.1 Cellulose hydrogen bonds in paper

The links in the cellulose chain are a type of sugar: -D-glucose.

The cellulose chain bristles with polar -OH groups. These groups form many

hydrogen bonds with OH groups on adjacent chains, bundling the chains

together. Viewed under a microscope, it is possible to see a network of

cellulose fibers and smaller offshoots from the fibers called fibrils.

Figure 1.2 Fibrils are offshoots of fibers Figure 1.3 Fibrils network

Figure 1.2 and 1.3 show fibers and fibrils network to form a matrix,

which becomes coated with Portland cement. When these networks or

matrices of fibers and fibrils dry, they intertwine and cling together with the

power of the hydrogen bond.

1.5 FLYASH

Flyash is a by-product of the combustion coal in the thermal plants.

It is removed by the dust collection system as fine particle residue from the

combustion gases before they are discharged into atmosphere.

5Depending upon the collection system, varying from mechanical to

electrical precipitators or bag houses and fabric filters, about 85% to 90% of

the ash from the flue gases is retrieved in the form of flyash. Flyash accounts

for 76% to 8 % of the total coal ash and the remainder is collected as bottom

ash or boiler slag. The bottom ash and boiler slag are much coarser and are

not pozzolanic in nature. It is thus important to recognize that all the ash is not

flyash and the flyash produced by different power plants is not equally

pozzolanic.

Testing shows that the bricks meet or exceed the performance

standards listed in ASTM C 216 for conventional clay brick. It is also within

the allowable shrinkage limits for concrete brick in ASTM C 55, and standard

specification for Concrete Building Brick. It is estimated that the production

method used in fly ash bricks will reduce the embodied energy of masonry

construction by upto 90% (Chusid et al 2009).

1.6 CURRENT RESEARCH TRENDS

In the last decade, a large demand has been placed on building

material industry especially owing to the increasing population which causes

a chronic shortage of building materials. As a result, civil engineers have been

challenged to convert the industrial wastes into useful building and

construction materials. Accumulation of unmanaged waste especially in

developing countries has resulted in an increased environmental concern.

Recycling of such wastes into building materials appears to be viable solution

not only to such pollution problems but also to the problem of economic

design of buildings.

The current pool of knowledge pertaining to papercrete was

obtained predominately through many anecdotal field experiments and

6observations. Yet very little by way of peer reviewed research exists in regard

to this material.

1.7 OBJECTIVES OF THE STUDY

The objectives of the present investigation are:

To utilize the waste materials like paper, flyash etc, in the

process of manufacturing new type of eco-friendly bricks,

namely papercrete bricks.

To manufacture and study the strength and durability of the

papercrete bricks in order to effectively use these papercrete

bricks commercially for construction purposes.

To extend the investigation further to study the structural

behavior of the papercrete brick masonry experimentally and

theoretically.

1.8 METHODOLOGY OF THE STUDY

In order to accomplish the aforesaid objectives, the research work

has been divided into nine major parts. They are:

(i) Material collection

(ii) Study of properties of materials

(iii) Specimen making

(iv) Preliminary tests

(v) Optimization of mix

(vi) Behavioural studies on the papercrete bricks and masonry

units

7(vii) Comparison of results with conventional bricks

(viii) Comparison of results with software analysis

(ix) Viability and cost analysis

PROPERTIES OF MATERIALS

MAKING THE SPECIMEN

PRELIMINARY TESTS

COMPRESSIVE STRENGTH PERCENTAGE OF WATERABSORPTION

BIO-DEGRADATION

MIX OPTIMIZATION

STUDIES ON STRENGTH OFPAPERCRETE BRICKS

COMPARISON WITHCONVENTIONAL BRICKS

VIABILITY AND COSTANALYSIS

CONCLUSION /SUGGESTION

STUDIES ON BEHAVIOUR OFPAPERCRETE MASONRY UNIT

COMPARISON WITH FEMANALYSIS

Figure 1.4 Methodology Flow chart

The flowchart in Figure 1.4 represents the methodology of the

present work and describes each and every stage of work as well.

81.8.1 Collection of Materials

To attain these goals, materials were collected from various

sources. Material collection is the basic and important step in any project.

Yet, the material that is used in a project should not cause any damage to the

environment. In the study, paper is the main constituent material. Seshasayee

paper board (SPB) mill, Pallipalayam (3 km from the institution) and TNPL

paper mill, Karur (30 km from the Institution) are nearby. Both are ISO

certified paper mills.

Also a lot of small paper mills (Cardboard manufacturing factories)

are surrounded by our locality. Papers are collected by two forms. (i) slurry

form and (ii) dry form. Slurry form (Paper pulp) was bought from SPB and

TNPL. Dry form i.e. old newspapers especially The Hindu is collected from

college hostel and college Library. Of these two forms, slurry form is not

good enough in fibre content because the slurries are the final output effluent

after recycling process.

So the news papers were collected and converted to slurry form

(paper pulp) using small flour machine. Flyash was collected from Mettur

Thermal Plant (dry ash) and the properties were studied. Ricehusk-ash, and

micro silica were purchased from an authorized company dealer and those

properties were studied. 43 grade cement and sand were collected and the

properties were studied as per BIS standard. Also, the water proofing

materials were bought from various dealers and the properties were studied

and it was conformed with the respective companies.

1.8.2 Preparation of Specimen

Waste papers or old news papers were collected from in and around

the locality and shredded into little pieces and then immersed in water bucket.

9After 15 days, the wet papers were taken out and poured into flavor machine.

The machine pulverized the paper and it was converted to paper slurry (paper

pulp). Normally the paper pulp would be in wet condition. Using pressed

filtering, the excess amount of water was expelled. Now, the paper pulp with

some residual water content was ready to mix with other ingredients. All the

ingredients (excluding paper pulp) were in dry state.

All the ingredients were poured into the mixer drum and mixed

uniformly electrically. Then the papercrete matrix was sent to collecting drum

through conveyor belt. Here the moulds received the matrix and pressing

unit compressed the fresh matrix with 10 kN/mm2 hydraulically. Then the

bricks were taken out from mould. The size of the papercrete bricks was

230mm X 110mm X 70mm. Within 15days, i.e. after hearing the metallic

sound when strikeout the brick surface, the specimen was ready for testing.

1.8.3 Optimization of Mix Through Preliminary Tests

As per Indian standards, BIS recommends (IS:1077-1992 and

IS:3495-1992) only four tests for clay bricks, i.e. determination of

(a) compressive strength, (b) water absorption, (c) efflorescence and

(d) warpage.

Of these tests, efflorescence and warpage are observation tests. In

this regard, compressive strength and percentage of water absorption are the

main criteria for influencing the optimization of papercrete mix.

In these stages, paper and cement are the main essential materials

for papercrete matrix. Additionally, flyash and/or ricehusk ash and/or silica

fume are added with and without sand. From more than 24 trial mixes,

successive mix was found out. In order to improve the resistant of water

absorption, different types of water proofing agents were added in desirable

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dosage to papercrete matrixes. Finally, depending upon the compressive

strength, percentage of water absorption and also bio-degradation test, the

papercrete mix was optimized.

1.8.4 Studies on Papercrete Bricks and Masonry Unit

The flyash based coated papercrete bricks were studied for

compressive strength, percentage of water absorption, acid resistance,

behaviour under elevated temperature, sorptivity and thermal conductivity.

Before the masonry construction, the loading frames were designed and the

set up was installed on rigid firmed floor in structural engineering laboratory.

In the first stage, loading frame was tested without infilled masonry and

recorded the behaviour of frame using Prosof software. Then, flyash based

papercrete brick masonry and conventional clay brick masonry were infilled

in the loading frame separately. The behaviour of infilled masonry walls were

studied.

1.8.5 Comparison of Results

The results from compressive strength, percentage of water

absorption, acid resistance and sorptivity of flyash based papercrete bricks

were compared with conventional clay bricks and modular flyash bricks. The

results from the behaviour of infilled flyash based papercrete brick masonry

wall were compared with conventional clay brick masonry wall. Also a model

infilled flyash based papercrete brick masonry wall is created using ANSYS

software and compared with experimental results.

1.8.6 Viability and Cost Analysis

The preliminary test results show some negative points. But by

taking the efforts from literature support and discussing with field and

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academic experts, the negative points were rectified by using internal and

external water proofing admixtures. So the coated papercrete bricks are the

viable and sustainable material in nature and environment.

The cost of the material plays an important role in the construction

industry. The cost analysis of papercrete bricks was studied at the end of the

project and it was compared with conventional clay and modular flyash

bricks. The cost of conventional clay bricks and modular flyash bricks were

calculated based on July 2011 rate at Namakkal District, TamilNadu, India.

1.9 ORGANISATION OF THE THESIS

The thesis consists of nine chapters. The first chapter gives a brief

introduction to the investigations carried out and explains the research

significance of the proposed investigation. Chapter 1 presents the objectives

of the study and methodology to be followed for the research work. Chapter 2

reviews critically the previous studies in the fields of utilization of waste

materials and papercrete. Towards the end of this chapter, a summary of

earlier works and the scope of the present investigation are discussed in detail.

Chapter 3 describes the properties of papercrete ingredients.

Chapter 4 deals with the effect of mineral admixture in papercrete

bricks. In this chapter the effects of addition of flyash, micro silica, rice husk

ash, sand and cement on the various mechanical properties like compressive

strength, water absorption were studied. Concluding remarks of these studies

are presented at the end of the chapter. Based upon the chapter 4, some

negative observations have been faced. Rectifications of these problems are

given in Chapter 5 under the title of Papercrete mix optimization with flyash

and based on the trial mixes, the papercrete mix was optimized. In view of

that, bio-degradation test was conducted on flyash based papercrete building

bricks. The chapter deals with the studies on the micro characterization of

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papercrete bricks also and at the end of the chapter concluding remarks of the

studies are noted. Chapter 6 is devoted to study the strength and durability of

the coated flyash based papercrete bricks. Finally, it presents a comparison of

these results with conventional brick results.

In Chapter 7, the strength and behavior of flyash based papercrete

masonry are delineated. In this chapter, ANSYS modal has been proposed in

order to compare and verify the results. Cost analysis of flyash based

papercrete brick is done in Chapter 8 and also it is compared with the cost of

the conventional brick. Finally, the conclusions arrived at in each chapter are

summarized in Chapter 9. At the end of this chapter, the social outcome of the

project in the present research work is highlighted and the scope for future

work is also suggested.