PAPER

India’s per capita consumption of paper is around 4.00 Kg.. With the expected increase in literacy rate and growth economy, an increase in per capita consumption of paper is expected. The demand for upstream market of paper products like, tissue paper, tea bags, filter paper, lightweight online-coated paper, medical grade coated paper etc., is growing up. Due to this tremendous increase in use of paper, 1600 m³ papers are wasted in India per day. Even though the waste papers are recycled in paper industry only 29% of waste paper is recycled. It is low in comparison to the global average of 36%. It is the major waste in India. So only the paper was selected as an important material in this project. The following are the properties of the  paper, which was used in this project.

Chemistry

          Paper is principally wood cellulose, which is considered as fibrous material. Cellulose is the second most abundant material on earth after rock. It is the main component of plant cell walls, and the basic building block for many textile and for paper. Cellulose is a natural polymer, a long chain of linked sugar molecules made by the linking of smaller molecules. Fig shows the cellulose hydrogen bonds.

Cellulose hydrogen bonds

The links in the cellulose chain a type of sugar, ß-D glucose. The cellulose chain bristles with polar –OH groups. These groups form many hydrogen bonds with –OH groups on adjacent chains, bundling the chain together. The chains also pack regularly in places to form hard, stable, crystalline regions that give the bundled chains even more stability and strength.

 Microscopic view of cellulose

Fig  shows the microscopic view of cellulose structure. It shows the network of cellulose fibres and smaller offshoots from the fibres called fibrils.

Physical behaviour

          Even though the chemical behaviour of the paper is suitable for papercrete, the physical behaviour of the paper is also taking effect in the physical behaviour of papercrete. The tensile strength of the paper also seems to be sufficient for the task. When applying a pull on a single sheet of paper on its edges, it has a great strength. Ripping a piece of paper is much easier than pulling it part. So it denotes the shear strength of paper is not as great as its tensile strength. But, when ripping the hundreds of paper it is not an easy task. So, it shows that it has more shear strength.

FLY ASH

With the boom population and industrial growth, the need for power has increased manifold. Nearly73% of India’s total installed power generation capacity is thermal, of which 90% is coal-based generation, with diesel, wind, gas and stream making up the rest. Thermal power generation through coal combustion produces minute particles of ash that causes serious problem. Commonly known as fly ash. These ash particles consists of silica, alumina, oxides of iron, calcium, magnesium and toxic heavy metals like lead, arsenic, cobalt, and copper.

          The 80-odd utility thermal power stations in India use bituminous coal and produce large quantities of fly ash. According to one estimate up to 150 million tones of fly ash will be produced in India during the year 2000. It is expected that the quantity of fly ash available will touch the figure of 1000 million KN per annum. The disposal of such a large quantities of fly ash is certainly a gigantic problem and a matter of national concern. This poses problem in form of land use, health hazards, and environmental dangers.

          The prevalent particle is to dump fly ash on wastelands, and this has lain to waste thousands of hectares all over the country. To prevent the fly ash from getting airborne, the dumping sites have to be constantly kept wet by sprinkling water over area. And in India, the sites are not lines and leads to seepage, contaminating groundwater and soil. It lowers the soil fertility and contaminates surface and ground water as it can leach into subsoil. When fly ash gets into the natural draining system, it results in siltation and clogs the system. It also reduces the pH balance and portability of water. Fly ash interferes with the process of photosynthesis of aquatic plants and thus disturbs the food chain.

Properties

          Fly ash is a residue resulting from combustion of pulverized coal or lignite in thermal power plants. About 80% of total ash is in finely divided form, which is carried away with flue gases and is collected by electrostatic precipitator or other suitable technology. This ash is called as dry ash or chimney or hopper ash. The balance 20% of ash gets collected at the bottom of the boiler and is referred as bottom ash. Fly ash is very fine comparable to cement, however some particles have size less than 1 micron in equivalent diameter

Chemical composition of Fly Ash.

Components	Percentage (%)
Silica as Sio2	35-59
Iron as Fe2O3	0.5-2
Alumina as Al2O3	20-33
Calcium as CaO	5-16
Magnesium as MgO	1-5.5
Sulphate as So3	0.5-1.5
Loss on ignition	1-2

Above the Table gives the chemical component of Fly ash. Fly ash posses pozzolana characteristics. Pozzolana are defined as silicious and aluminous materials, which in themselves posses little or no cementitious value but, will in finally divided from and in the presence of moisture chemically react with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. So this pozzolanic material can be used for the manufacture of cement, concrete, and lime/cement based bricks/blocks.

CEMENT PROPERTIES

The cement is obtained by burning at very high temperature a mixture of calcareous and argillaceous materials. The mixture of ingredients should be intimate and they should be in correct proportion. The calcined product is known as clinker. A small quantity of gypsum is added to the clinker and it is then pulverized in to very fine powder, which is known as cement.

          Among the various types of cement, ordinary Portland cement (OPC) is by far the most important type of cement. The OPC was classified in to three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of the cement at 28 days when tested as per IS 4031-1988. If the 28 days strength is not less than 33 N/mm², it is called as 33-grade cement.

The chemical composition of ordinary Portland cement is tabulated below

Oxide	Percentage (%)
CaO	60-67
SiO2	17-25
Al2O3	S3-8
Fe2O3	0.5-6
MgO	0.1-4
Alkalies (K2O, N2O)	0.4-1.3
SO3	1.3-3

Following are the important properties of good cement, which primarily depend upon its chemical composition, thoroughness of burning and fineness of grinding.

o   It gives strength to the masonry.

o   It is an excellent binding material.

o   It is easily workable.

o   It offers good resistance to the moisture.

o   It possesses a good plasticity.

o   It stiffens or hardens easily.

Physical Characteristics Of OPC

Types of cement		33grade	43grade	53grade
Finess(m2/kg)Mm		225	225	225
Soundness by	Le chatelier (mm) max	10	10	10
	Auto clave (%)max	0.8	0.8	0.8
Setting time	Initial(mts)mm	30	30	30
	Final(mts)mm	600	600	600
Compressive strength	1day Mpa	N.S	N.S	N.S
	3days Mpa	16	23	27
	7days Mpa	22	33	37
	28days Npa	33	43	53

Chemical Characteristics Of OPC

Type of cement	33grade	43grade	53grade
Lime saturation factor (%)	0.66Mm 1.02max	0.66Mm 1.02Max	0.8Mm 1.02max
Alumina iron ratio (%)Mm	0.66	0.66	0.66
Insoluble residue (%)max	4	2	2
Magnese(%)max	6	6	6
Sulphuric anhydride	2.5% max when C3A is 5	2.5% max when C3A is 5	2.5% max when C3A is 5
	3% Max when C3A is >5	3% Max when C3A is >5	3% Max when C3A is >5
Less on ignition(%)max	5	5	4

SAND

The sand particle consists of small grains of silica (SiO₂). It is formed by the decomposition of sand stones due to various effects of weather. According to the natural resources from which the sand is obtained, it is of the following three types.,

(i)      Pit sand

            (ii)     River sand

(iii)    Sea sand

          According to the size of grains, the sand is classified as fine, coarse and gravel. The sand passing through a screen with clear openings of 1.5875 mm is known as fine sand. It is mainly used for plastering. The sand passing through a screen with clear openings of 3.175 mm is known as the coarse sand. It is generally used for masonry work. The sand passing through a screen with clear openings of 7.62 mm is known as the gravel sand. It is generally used for concrete work.

Properties

The following are the properties of good sand

o   It should be chemically inert.

o   It should be clean and coarse.

o   It should be free from any organic or vegetable matter. Usually   3- 4% of clay is permitted.

o   It should contain sharp, angular, coarse and durable grains.

o   It should not contain salts, which attracts moisture from atmosphere.

o   It should be well graded, i.e., it should contain particle of various sizes in suitable proportion. The fineness modulus of sand between 2 to 3.

METHODOLOGY

Papercrete derivatives like fibrous concrete and padobe was used in this project. The concept of that derivatives are different with each other. Concept of that two derivatives are given below.

FIBROUS CONCRETE

The basic idea that initiates this project is the way paper fibres hold Portland cement or perhaps the Portland cement adheres to paper fibres. When the water is added to paper and Portland cement drains from the mix, it comes out almost completely clear. There is no messy and Eco-unfriendly cement sediment left on the ground, running into waterways etc., papercrete can be produced using solar energy.

Papercrete matrix

Paper is principally wood cellulose. Cellulose is natural polymer. And Fig shows the links of cellulose bonds. The cellulose chain bristles with polar-OH groups. These groups form hydrogen bonds with -OH group on adjacent chains, bundling, the chain together. The chains also pack regularly in places to form hard, stable crystalline region that give the bundled chains even more stability and strength. This hydrogen bonding forms the basics of papercrete’s strength.  Fig shows the network of cellulose fibres and smaller offshoots from the fibres called fibrils. Fig   shows the papercrete matrix. In this, fibres and fibrils network forms a matrix, which becomes coated with Portland cement. When these networks of fibers and fibrils dry, they inter wine and cling together with the power of hydrogen bond. Coating this fiber with Portland cement creates a cement matrix, which encases the fibers for extra strength. Of course paper has more in it than cellulose.  Raw cellulose has comparatively rough texture. Clay, fly ash is added to make the cellulose very smooth. The great thing about the generic papercrete is how it traps air. When the water drains out and evaporates, it leaves the thousands of tiny air pockets. This is what makes the material light and good insulator.

          While adding more sand or glass to the mix results in a denser, stronger, more flame retardant material, but adds weight and reduces R- value. Heavy mixes with added sand, glass etc., increases strength and resistance to abrasion, but also reduces flexibility somewhat, adds weight and may reduce R-value. So the trick is finding the best mix for the application.