Jute Motar.pdf...

DEVELOPMENT OF MODIFIED REINFORCED JUTE MORTAR

INTRODUCTION

Chapter 01 Introduction atural fibers are prospective reinforcing materials and their use until now has been more traditional than technical. They have long served many useful purposes but the application of materials technology for the utilization of natural fibers as the reinforcement in concrete has only taken place in comparatively recent years. In developing countries construction of cement concrete building with durable design and low cost fiber reinforcement is a technological challenge. Fiber-reinforced concrete is concrete is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, glass fibers, synthetic fibers and natural fibers – fibers – each of which lend varying properties to the concrete. Carbon fibers use are restricted in cementitious composites on a commercial level due to economic consideration and their non-ecological performance. Natural fibers have the potential to be used as reinforcement to overcome the inherent deficiencies in cementitious materials. Considerable researches are being done for use of reinforcing fibers like jute, bamboo, sisal, akwara, coconut husk, sugarcane bagasse in cement composites mostly in case of building materials. Use of natural fibers in a relatively brittle cement matrix has achieved considerable strength, and toughness of the composite. The durability of such fibers in a highly alkaline cement matrix must be taken into consideration by effective modifications. A specific chemical composition has to be chosen that can modify the fiber surface as well as strengthen the cement composite.

1.1 Background Cement concrete composite is the most important building material and its consumption is increasing in all countries. The only disadvantage of cement concrete is its brittleness, with relatively low tensile strength and poor resistance to crack opening and propagation and negligible elongation at break. To overcome these discrepancies reinforcement with dispersed fibers might play an important role. Steel is the conventional reinforcing material in concrete. Although steel enhances the strength and modulus of concrete but it lacks the ability to absorb mechanical impact. The steel makes the reinforced cement concrete (RCC) structure heavy and in due course of time as a result of water/moisture diffusion through micro crack Department of Civil Engineering, National Institute of Technology Srinagar

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INTRODUCTION

developed in the RCC structure steel starts corroding leading to failure of the concrete. On the contrary, if the micro crack formation and propagation can be minimized by dispersion of short fibers, the mechanical properties as well as the durability of the concrete can be improved. Such a system would be able to bear high level static as well as dynamic stress. Natural (cellulosic) fibers might offer the opportunity as a convenient reinforcing agent in concrete composite due to its low density and high tensile property. In recent years, considerable research efforts are found to develop high-strength, natural fibers reinforced concrete composites, mostly for using as building and construction materials. Natural fibers, isolated isol ated from plants, are classified into three categories, cate gories, depending on the part of the plant they are extracted from. The first category is the so called fruit fiber (e.g., coir, cotton, etc.) which are extracted from fruits of the plant. The second category of the fiber is found in the stems of the plant (e.g., jute, flax, ramie, hemp, etc). Such fibers are known as bast fiber. The third category is the fibers extracted from the leaves (e.g., sisal, date palm, oil palm, etc.). Polymer modified jute fibers have been decided to be used as reinforcing element in cement concrete in which polymer will chemically bridge jute in one side and cement on the other side. Polymer modified jute fiber is expected to act as a flexible reinforcing agent in cement concrete enabling it to transmit both static and dynamic stresses to its surrounding bulk as well as absorb a portion of the stress by virtue of its flexible nature. An optimized weight fraction of polymer modified jute fiber in cement concrete may lead to excellent mechanical properties. It has been anticipated that modification of jute fiber with polymer will reduce degradation possibilities. Fiber reinforced concrete has been investigated extensively to make light weight corrosion free structural materials. There are global attempts to use natural fibers as reinforcing agent in cement concrete matrices. The advantages of natural fibers over the conventional reinforcing fibers like glass, synthetic (e.g., polypropylene, polyethylene and polyolefin, polyvinyl alcohol), carbon, steel etc., are abundant availability, low cost, less abrasiveness, ability to absorb mechanical impact, easy to handle and process and environmental friendliness. These composites can be used in various fields of applications such as permanent frameworks, paver blocks, wall panels, pipes, long span roofing elements, strengthening of existing structures and structural building members. The natural fiber reinforced concrete composites present enhanced strength and are likely to encounter a rangeof static overload and cyclic loading due to possible wind or earthquake loading. When concrete matrix cracks under load, the fibers bridge the cracks and transfer the loads to its surrounding bulk as well as absorb a portion of the load by virtue of Department of Civil Engineering, National Institute of Technology Srinagar

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INTRODUCTION

developed in the RCC structure steel starts corroding leading to failure of the concrete. On the contrary, if the micro crack formation and propagation can be minimized by dispersion of short fibers, the mechanical properties as well as the durability of the concrete can be improved. Such a system would be able to bear high level static as well as dynamic stress. Natural (cellulosic) fibers might offer the opportunity as a convenient reinforcing agent in concrete composite due to its low density and high tensile property. In recent years, considerable research efforts are found to develop high-strength, natural fibers reinforced concrete composites, mostly for using as building and construction materials. Natural fibers, isolated isol ated from plants, are classified into three categories, cate gories, depending on the part of the plant they are extracted from. The first category is the so called fruit fiber (e.g., coir, cotton, etc.) which are extracted from fruits of the plant. The second category of the fiber is found in the stems of the plant (e.g., jute, flax, ramie, hemp, etc). Such fibers are known as bast fiber. The third category is the fibers extracted from the leaves (e.g., sisal, date palm, oil palm, etc.). Polymer modified jute fibers have been decided to be used as reinforcing element in cement concrete in which polymer will chemically bridge jute in one side and cement on the other side. Polymer modified jute fiber is expected to act as a flexible reinforcing agent in cement concrete enabling it to transmit both static and dynamic stresses to its surrounding bulk as well as absorb a portion of the stress by virtue of its flexible nature. An optimized weight fraction of polymer modified jute fiber in cement concrete may lead to excellent mechanical properties. It has been anticipated that modification of jute fiber with polymer will reduce degradation possibilities. Fiber reinforced concrete has been investigated extensively to make light weight corrosion free structural materials. There are global attempts to use natural fibers as reinforcing agent in cement concrete matrices. The advantages of natural fibers over the conventional reinforcing fibers like glass, synthetic (e.g., polypropylene, polyethylene and polyolefin, polyvinyl alcohol), carbon, steel etc., are abundant availability, low cost, less abrasiveness, ability to absorb mechanical impact, easy to handle and process and environmental friendliness. These composites can be used in various fields of applications such as permanent frameworks, paver blocks, wall panels, pipes, long span roofing elements, strengthening of existing structures and structural building members. The natural fiber reinforced concrete composites present enhanced strength and are likely to encounter a rangeof static overload and cyclic loading due to possible wind or earthquake loading. When concrete matrix cracks under load, the fibers bridge the cracks and transfer the loads to its surrounding bulk as well as absorb a portion of the load by virtue of Department of Civil Engineering, National Institute of Technology Srinagar

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INTRODUCTION

its flexible nature. Several investigations have been carried out with different lignocellulosic fibers like, wheat straw, rice straw, coir, hazelnut shell, bagasse, oil palm residues, arhar stalks, etc., to find the potentiality of natural fibers as an effective reinforcementin concrete composites. But no report is found on the use of jute fiber as reinforcement in cement concrete. Based on the present scenario it has been anticipated that the jute fiber reinforced cement concrete may find potential application as structural items in construction industry. Being a potential agricultural product, the use of jute as reinforcing fiber in cement concrete will promote jute farming industries as well as produce better advanced composites.

1.2 Methodology The approach adopted over the course of the project was divided into several divisions after which the use of Jute concrete was found out through the analysis of properties and its behavior. 

Chemical modification of jute fiber.



Characterization of unmodified and chemically modified jute fiber.



Fabrication of jute reinforced cubic blocks & beams.



Testing and characterization of jute fiber reinforced cement

Department of Civil Engineering, National Institute of Technology Srinagar

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INTRODUCTION

Figure 1: (a) Soaked jute in NaOH, (b) Casting of jute mortar, (c) Jute mortar paver blocks

1.3 Deliverables of this project 

Selective choice and composition optimization of chemical and polymer for modification of jute fiber.



Optimized process development for mixing and casting of jute fiber reinforced cement concrete composite.



Optimized fiber length and loading in cement composite for best possible mechanical properties.


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INTRODUCTION

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Literature Review

Chapter 02 Literature review Introduction Fibers have been used to reinforce brittle materials from time immemorial, dating back to the Egyptian and Babylonian eras, if not earlier. Straws were used to reinforce sun-baked bricks and mud-hut walls, horse hair was used to reinforce plaster, and asbe stos fibers have been used to reinforce Portland cement mortars. Research in the late 1950s and early 1960s by Romualdi and Batson (1963) and Romualdi and Mandel (1964) on closely spaced random fibers, primarily steel fibers, heralded the era of using the fiber composite concretes we know today. In addition, Shah and Rangan (1971), Swamy (1975), and several other researchers in the United States, United Kingdom, Japan, and Russia embarked on extensive investigations in this area, exploring other fibers in additi on to steel. By the 1960s, steel-fiber concrete began to be used in pavements, in particular. Other developments using bundled fiberglass as the main composite reinforcement in concrete beams and slabs were introduced by Nawy et al. (1971) and Nawy and Neuwerth (1977). From the 1970s to the present, the use of steel fibershas been well established as a complementary reinforcement to increase cracking resistance, flexural and shear strength, and impact resistance of reinforced concrete elements both in situ cast and precast.

2.1 General Characteristics Concrete is acknowledged to be a relatively brittle material when subjected to normal stresses and impact loads, where tensile strength is approximately just one tenth of its compressive strength. As a result for these characteristics, concrete flexural members could not support such loads that usually take place during their service life. Historically, concrete member reinforced with continuous stresses

reinforcing bars to withstand tensile

and compensate for the lack of ductility and strength. Furthermore, steel

reinforcement is adopted to overcome high potentially tensile stresses and shear stresses at critical location in concrete member.


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Literature Review

Figure 2: NATURAL FIBERs. (1)Paper pulp (2).Jute (3)Elephant Grass (4)Bamboo (5)coconut husk (6)Sisal

Even though the addition of steel reinforcement significantly increases the strength of concrete,the development of micro cracks must be controlled to produce concrete with homogenous tensile properties. Concrete is weak in tension. Micro cracks begin to generate in the matrix of a structural element at about 10 to 15% of the ultimate load, propagating into macro cracks at 25 to 30% of the ultimate load. Consequently, plain concrete members cannot be expected to sustain large transverse loading without the addition of continuous-bar reinforcing elements in the Department of Civil Engineering, National Institute of Technology Srinagar

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Literature Review

tensile zone of supported members such as beams or slabs. The developing micro cracking and macro cracking, however, still cannot be arrested or slowed by the sole use of continuous reinforcement. The function of such reinforcement is to replace the function of the tensile zone of a section and assume the tension equilibrium force in the section. The introduction of fibers is brought in as a solution to develop concrete with enhanced flexural and tensile strength, which is a new form of binder that could combine Portland cement in bonding with cement matrices. Fibres are most generally discontinuous, randomly distributed throughout the cement matrices. The addition of randomly spaced discontinuous fiber elements should aid in arresting the development or propagation of the micro cracks that are known to generate at the early stages of loading history. Although fi bers have been used to reinforce brittle materials such as concrete since time immemorial, newly developed fibers have been used extensively worldwide in the past three decades. Different types are commercially available, such as steel, glass, polypropylene, or graphite. They have proven that they can improve the mechanical properties of the concrete, both as a structure and a material, not as a replacement for continuous — bar reinforcement when it is needed but in addition to it..


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Literature Review

2.2 Typical properties of fiber:

Table 1: Typical properties of fiber Fiber Type

Diameter .001 in.

Specific Gravity

E, ksi x 1000

Tensile Strength, ksi

Strain at Failure, %

4-40 4-13 4-5

7.8 7.8 2.5-2.7

29 23.2 10.44-11.6

50-250 300 360-500

3.5 3 3.6-4.8

20-160 1-40 4-3

0.9 0.96 1.38

0.5 725-25 1.45-2.5

80-110 29-435 80-170

8 3-80 10-50

4-47 .0008-1.2 3-35

1.44 1 .44 2.6-3.4 1.9

9-17 23.8-28.4 33.4-55.1

525 29-500 260-380

2.5-3.6 2-3 5-1.5

8-4.7

1.5

1.45-5.8

44-131

-

<8 4-16 2-16 4-8 40-160 17

1.12-1.15 1.5 1.02-1.04 0.96 -

1.89-3.77 2.76-3.77 4.79-5.8 3.7-4.64 .076-.464 .716

41-82 17-29 51-73 36-51 26

3-5 10-25 1.5-1.9 3.6

Steel High Tensile Stainless Glass Polymeric Polypropylene Polyethylene Polyester Amarid Asbestos Carbon Natural Wood Cellulose Sisal Coir(Coconut) Bamboo Jute Akwr Elephant Grass

The introduction of fiber additions additions to concrete was aimed primarily at enhancing the tensile strength of concrete. As is well known, the tensile strength is 8 to l4% of the compressive strength of normal concretes with resulting cracking at low stress levels. Such a weakness is partially overcome by the addition of reinforcing bars, which can be either steel or fiberglass, as main continuous reinforcement in beams and one-way and two-way structural slabs or slabs on grade As indicated earlier, the continuous reinforcing elements cannot stop the development of micro cracks. Fibers, on the other hand, are discontinuous and randomly distributed in the matrix, in both the tensile and compressive zones of a structural element. They are able to add to the stiffness and crack — control control performance by preventing the micro cracks from propagating and widening and also by increasing ductility due to their energyabsorption capacity. In the past few decades, various materials have emerged to ease the construction process. Jutereinforced fiber is one such material that offers various benefits in structures. Jute concrete is a Department of Civil Engineering, National Institute of Technology Srinagar

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Literature Review

material which consists of jute fiber in small pieces mixed in the form of a slurry with Portland Cement or clay and/or other soil added. The thick mix can be poured into different moulds and create blocks, panels and and Inumerable other shapes.

2.3 Advantages of Jute Mortar Advantages of Jute Mortar are more than ordinary Mortar cement.To mention,some are: 

The main material in preparation is Jute which is easily,freely,abundantly and at low cost available.



Jute Mortar Blocks have more compressive strength than other ordinary mortar block.



Due to Tensile properties of fiber which get embed when jute is mixed with mortar, Jute mortar blocks have more tensile strength.



Jute Mortar blocks are light weight due to which they can be best alternative when roofing is considered.



Inspite of adding jute, there is no change in appearance and as such jute mortar block and ordinary mortar block look same.



Jute Mortar is Aesthetically pleasing.



It has very high shear strength as block.



Jute mortar cab be used in decorative moulds and blockwork.



Walls made of jute mortar can be easily painted.Even more jute gives a pleasing texture when it is exposed to surface.



As the fiber blocks the voids, it has high acoustic performance,thus can be used in seminar halls and cinemas.

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Jute mortar is very workable and thus can be formed into different shapes such as blocks,panels and sheets with ease.



Required machinery is readily available even with poor farmers.



Jute mortar cab be used for simple furniture in homes.

2.4 Dis-Advantages of Jute Mortar There are some dis-advantages which should be taken care of : 

Modification of jute requires an expertise.



Chemicals are required which may not be easily available.



Preparation requires time, as such may not get prepared when urgently required.



When it comes to moisture resistance, Jute Mortar behaves poor.



Can get disintegrate when exposed to water for prolonged periods of time


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Literature Review

Chemical Composition of Jute Fiber


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Literature Review

2.5 Introduction Jute is a long, soft, shiny vegetable fiber that can be spun into coarse, strong threads. It is produced from plants in the genus Corchorus, which was once classified with the family Tiliaceae, more recently with Malvaceae, and has now been reclassified as belonging to the family Sparrmanniaceae. The primary source of the fiber is Corchorus olitorius, but it is considered inferior to Corchorus capsularis. "Jute" is the name of the plant or fiber that is used to make burlap, Hessian or gunny cloth. Jute is one of the most affordable natural fibers and is second only to cotton in amount produced and variety of uses of vegetable fibers. Jute fibers are composed primarily of the plant materials cellulose and lignin. It falls into the bast fiber category (fiber collected from bast, the phloem of the plant, sometimes called the "skin") along with kenaf, industrial hemp, flax (linen), ramie, etc. The industrial term for jute fiber is raw jute. The fibers are off-white to brown, and 1 – 4 metres (3 – 13 feet) long. Jute is also called "the golden fiber" for its color and high cash value.

Figure 3: Nonwood fibers from herbaceous plants


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Literature Review

2.6 Production: Jute is a rain-fed crop with little need for fertilizer or pesticides, in contrast to cotton's heavy requirements. Production is concentrated mostly in India's states of Assam, Bihar, West Bengal and Bangladesh. The jute fiber comes from the stem and ribbon (outer skin) of the jute plant. The fibers are first extracted by retting. The retting process consists of bundling jute stems together and immersing them in slow running water. There are two types of retting: stem and ribbon. After the retting process, stripping begins. In the stripping process, non-fibrous matter is scraped off, then the workers dig in and grab the fibers from within the jute stem. India is the world's largest producer of jute, but imported approximately 162,000 tonnes of raw fiber and 175,000 tonnes of jute products in 2011. India, Pakistan, and China import significant quantities of jute fiber and products from Bangladesh, as does the United Kingdom, Japan, United States, France, Spain, Côte d'Ivoire, Germany and Brazil. Extraction of Jute

Figure 4: Extraction of Jute Extraction of Jute


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Literature Review

2.7 Chemistry:Chemical Composition of Jute Fibre: Jute is a lingo cellulosic composite natural fiber. Cellulose, hemicelluloses and lignin are its major constituent components. chemical

Its three dimensional structure

and

different

physical,

and mechanical properties are resultant of various physical, chemical,

mechanical and hydrogen bonds formed between them. The chemical compositions of major commercial species of jute .

Figure 5: Lignocellulosic materials

Table 2: Chemical composition of Jute Constituents

Jute 60.0-63.0 21.0-24.0 12.0-130 0.4-1.0 0.2-1.5 0.80-1.9

C. Olitorius 58.0-59.0 22.0-25.0 13.0-14.0 0.4-0.9 0.2-0.5 0.8-1.6

0.7-1.2

0.5-1.2

C.Camsular’s

Alphacellulose Hemicellulose Lignin Fats & Waxes Pectin Protein or Nitrogenous matter, etc (%N2 x 6.25) Ash


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Literature Review

2.8 Physical Properties of Jute: Jute has unique characteristic properties for hard and soft fibre simultaneously. These are in short shown below:

Table 3: Physical properties of Jute A. 1

Macro & Micro Structure Ultimate Cell Length (L)

2

Ultimate Cell Breadth (B)

3 4 5 6

L/B Ratio(Average) Fiber Fitness Fiber Length (After carding) Density

7 8 9 B 10

Bulk Density Degree of crystallinity(X-ray) Angle of Orientation (X-ray) Moisture Absorption Moisture Regain

11

Transverse Swelling in water

C. 13

Mechanical Properties Tenacity

14 15

Elongation at Break Initial Modulus

16 17 18

Specific Torsional Rigidity Specific Flexural Rigidity Elastic Recovery

19 20 21 22 22 23 24 25

Specific work of Rupture Work Factor Thermal Properties Specific Heat Thermal Conductivity Heat of combustion Ignition Temperature Heat of Wetting

-Average -Range -Average -Range

2.50mm 08-6.00mm 18µm 10-25µm 110 1.3-4.0 tex 2.50 cm 1.46 g/cc 1.10-1.34 g/cc 0.4-0.5 g/cc 55-60% 7-9

-True -Apparent



- at 65% RH - at 100% RH - Diameter – wise - Cross-sectional area wise

13.8%

Single (gauge length-1 cm) Bundle(gauge length – 5cm)

30-50 gm /tex;0.29 – 0.48 N / tex 12 – 35 gf / tex;0.18 – 0.34 N / tex 1.0 – 1.8% 1700 – 3000 gf / tex;17-30 N/tex 11 2 0.9 – 1.7 x 10 dynes/cm

2

20%

2

0.4 – 0.5mN.mm / tex 2 2 0.7 – 0.8 mN.mm /tex From 3 g/den stress From 1.5% strain 2.7 mN/tex 0.5

75% 75%

1.36 x 103 J kg-1 , K-1 -1 2 427.3mWm ,K 17.5J/g 193 18.2 calories 


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Literature Review

2.9 MATERIALS USED TO MAKE JUTE MORTAR

In order to carry on this project and to prepare chemically modified Jute Mortar we used the following materials: 1.CEMENT:-We used Khyber cement ,43 grade for our project work.Cement must develop

the appropriate strength.It must represent the appropriate rheological behaviour.Generally same types of cements have quite different rheological and strength characteristics, particularly when used in combination with jute and other materials. 2.SAND: The zoning of the sand is based upon the cumulative percentage finer through sieve

600 mcron.Here the cumulative percentage finer is 25.4%, so the given sand sample is zoneII according to the table 2, which is recommended by IS code Cummulative %age finer through 600 micron sieve 15-34 35-59 60-79 80-100

Zone of Sand

I II III IV

Figure 6: (a) Khyber Cement Bag (b) Sand

3.SODIUM HYDROXIDE: Sodium hydroxide (NaOH), also known as lye and caustic soda,

is an inorganic compound. It is a white solid and highly caustic metallic base and alkali salt which is available in pellets, flakes, granules, and as prepared solutions at a number of different concentrations. Sodium hydroxide forms an approximately 50% (by weight)


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Literature Review

saturated solution with water. In this project we used Rankem Sodium hydroxide flakes M.W 40.00

Figure 7: Sodium Hydroxide

4.JUTE:There are various grades of Jute available in market each having its own

characteristics and properties. But we have used Jute in threaded form available in market. This type of Jure is cheap, readily available and easy to handle. Moreover it is available in any quantity. Approximate weight of each jute ball was 80 gms. The Jute was cut in small required length so that proper requirement may be fulfilled.

Figure 8: Jute Threaded Balls


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Literature Review

5.WATER:We used the tap water water to make the mortar mixed for the project work. This

must be free from salts and other impurities which reduce the strength of mortar. 6.POLMER :We used Commercially available aqueous emulsion of Carboxylated Styrene-

Butadiene Copolymer based polymer latex was used to modify the jute fibers. The solid content of undiluted polymer latex was 41%.

Figure 9: Carboxylated Styrene-Butadiene Copolymer


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Modification and characterization of Jute Fiber

Chapter 03 Modification and characterization of jute fiber 3.1. Materials for modification Jute fibers obtained from thread balls available in market were used. Analytical grade sodium hydroxide (NaOH) and commercially available carboxylated styrene-butadiene copolymer based polymer latex (Sika Polymer latex Power) were used for fiber surface modification.

3.2. Chemical modification of jute fiber From the polar chemical nature and structure of natural fiber it appears that such fibers can interact with polar nature of cement concrete. This concept justifies the reinforcing action of jute in cement concrete. Simultaneously due to polar character of natural fiber, viz., jute, it shows hydrophilic character. Such hydrophilicity might lead to depletion of water from the wet concrete mix as well as it might degrade in due course of time as a result of microbial attack. To overcome such shortcomings jute fibers need suitable physicochemical modification before incorporation in concrete matrix. It was anticipated that after modification with alkali and other chemical constituents, microbial degradation of jute fiber can be either delayed or prevented.

3.3. Modification with alkali The jute fibers were cut to ~6 cm of length and soaked in 0.25, 0.5 and 1.0% (w/v) NaOH solution at ambient temperature maintaining a fiber to liquor ratio of 1:30. The fibers were kept immersed in the alkali solution for 0.5, 1, 2, 4, 8, 16, 24, 36 and 48 h. The alkali treated fibers were then washed several times with distilled water to remove excess alkali from the fiber surface. The final pH was maintained at 7.0. The fibers were then air dried at room temperature for 24 h followed by oven drying at 55oC for 24 h. The plausible reaction between jute fiber and alkali is shown in fig


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Modification and characterization of Jute Fiber

Equation 1: Plausible reaction between jute fiber and alkali

3.4. Modification with polymer latex

Commercially available aqueous emulsion of carboxylated styrene-butadiene copolymer based polymer latex was used to modify the jute fibers. The solid content of undiluted polymer latex was found to be 41%. Alkali treated jute fibers were dipped into 0.25, 0.5, and 1.0% (v/v)polymer latex for 24 h, maintaining a liquor ratio 1:30 at ambient condition. The fibers were then air dried at room temperature for 24 h followed by oven drying at 55oC for 24 h. The plausible reaction chemistry of alkali treated jute fiber and polymer latex is shown in fig

Equation 2: Plausible reaction chemistry of alkali treated jute fiber and polymer la


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Experimental Procedure

Chapter 04 Experimental Procedure 4.1 MATERIALS:

The materials used in this study were ordinary OPC Khyber Cement (43 grade), fine sand, jute , sodium hydroxide (NaOH), carboxylated styrene-butadiene copolymer based polymer latex and tap water

Figure 10: Material during experimental procedure

4.2 Modification of Jute Fiber 4.2 (a) Modification with Alkali: The jute fibers were cut to ~6 cm of length and soaked in 0.25, 0.5 and 1.0% (w/v) NaOH solution at ambient temperature maintaining a fiber to liquor ratio of 1:30. The fibers were kept immersed in the alkali solution for 0.5, 1, 2, 4, 8, 16, 24, 36 and 48 h. The alkali treated fibers were then washed several times with distilled water to remove excess alkali from the fiber surface. The final pH was maintained at 7.0. The fibers were then air dried at room temperature for 24 h followed by oven drying at 55oC for 24 h.

Figure 11: Preperation of Jute


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Figure 12: (a)Jute soaked in NaOH (b) Jute soaked in Polymer (c) Jute in distilled water (d) Oven dried Jute

4.2(b) MODIFICATION WITH POLYMER LATEX: Commercially available aqueous

emulsion of carboxylate styrene-butadiene copolymer based polymer latex was used to modify the jute fibers. The solid content of undiluted polymer latex was found to be 41%. Alkali treated jute fibers were dipped into 0.25, 0.5, and 1.0% (v/v) polymer latex for 24 h, maintaining a liquor ratio 1:30 at ambient condition. The fibers were then air dried at room temperature for 24 h followed by oven drying at 55oC for 24 h .

Figure 13: After treated with Polymer


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4.3 CASTING AND MIXING: The test moulds are kept ready before preparing the mix.

Tighten the bolts of the moulds carefully because if bolts are not tight the cement mortar slurry comes out of the mould when vibration takes place. Then moulds are cleaned and oiled on all contact surfaces of the moulds and then place the mould on the smooth and even surface. The modified jute cement mortar is filled into modules in layers and then vibrated. The top surface of cement mortar is struck off level with a trowel. The sample code (e.g. MS1, 11, 22, 0.8%, 33 etc.) and date of casting ar e put on the surface of the cubes, beams and moulds. The mixes were prepared by weight proportion of modified jute (i.e. jute treated with different sol. Of NaOH & polymer) used as a cement mortar replacement material. A total 27 cube samples of 150mm x 150mm x 150mm size and 9 beams of 100mm x 100mm x 500mm were prepared from 1:3 design mix by weight and is reinforced with jute which is treated with different solutions of NaOH & carboxylated styrene butadiene latex

Figure 14: Pouring of modified Jute Cement slurry in sand-cement mix

Figure 15: Moulds for casting cubes and beams


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4.4 METHOD OF CASTING: The major problems encountered with jute fiber as a

reinforcing agent in cement matrix are its non-uniform dispersion due to agglomeration of the fiber and its hydrophilic nature. Hence to achieve a uniform dispersion of fibers in cement matrix jute is not directly mixed with sand & cement. A different technique was used in which chemically modified jute was estimated which is to used in the cement mortar as reinforcement in the next day and then the chemically modified

chopped fibers were

immersed for 24 h in half of the total volume of water required for mortar preparation in a container. Next the half of the total amount of cement required was added to wet jute in that container with constant stirring to obtain jute-cement slurry.

Figure 16: Preperation of Jute cement slurry

Figure 17: Mixing of slurry


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Figure 19: Mixing cement-sand


Figure 18:Pouring and adding of slurry to cement-sand mix

The jute cement slurry was then slowly poured into the cement mortar mix. The remaining amount of water was then added and the mixing was for further 5 min. The fresh cement mortar thus obtained was cast immediately in 150mm x 150mm x 150mm cubes and 100mm x 100mm x 500mm beams. After casting of cubes and beams the vibrator was used for the proper compaction of the jute reinforced cement mortar. And then all the moulds were allowed to setting. .

Figure 21: Filling mould with jute mortar

Figure 20: Vibrator used for compaction


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Figure 22:Vibrator used for compaction

The moulds were opened after 24hrs of casting. The plain cement mortar samples were placed in the water bath tank for curing after writing the sample code on them. But for the chemically modified jute cement mortar samples we place the in the open atmosphere for next 24 to 36 hours after writing the sample code and the place them in the water bath tank for curing.

Figure 23: Opening of moulds

All samples were cured in the water bath tank to make sure that maximum hydration process within the sample can take place.


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Figure 25: Casted samples


Figure 24:Curing of samples

4.5 TESTS PERFORMED ARE: We performed only two tests to compare the chemical ly modified reinforced jute cement

mortar with the normal mortar. These tests are following:



Compressive Strength Test



Flexural Strength Test

4.6 Test for Compressive strength of cement mortar & reinforced cement mortar cubes

To calculate the compressive strength of cement mortar cubes the universal testing machine (UTM) of load carring capacity of 40 Tonnes was used.


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Figure 26: Universal Testing Machine (UTM)

In this test the strength is obtained in tonnes. The measured compressive strength of the specimen shall be calculated by the maximum load applied to the specimen during the by the cross sectional area calculated from mean dimensions of the section and shall be expressed to the nearest MPa. Out of many test applied to the concrete, this is the utmost important which gives an idea about all the characteristics of concrete. By this single test one judge that weather concreting has been done properly or not. These specimens are tested by compression testing machine after 14 days curing or 28 days curing. Load should be applied gradually at the rate of 140 kg/cm 2 per minute till the Specimens fails. Load at the failure divided by area of specimen gives the compressive strength of concrete. Calculations:

Compressive strength = Maximum Load / Area = P/A Where: P = max. load A = area of the specimen


Page 28



Figure 27:Testing of cube with 0.25% sol of NaOH treated Jute

4.7Test for flexural strength of cement mortar & reinforced cement mortar beams To determine the Flexural Strength of cement mortar, which comes into play when a slab

with inadequate sub-grade support is subjected to wheel loads and / or there are volume changes due to temperature / shrinking. Test specimens shall be prepared by moldings concrete to a beam section, curing and storing in accordance with standard procedure. The section of the beam shall be square of 100 mm or 150 mm. The overall length of the specimen shall be 4d to 5d. The ratio of d to the maximum particle size of aggregate shall be not less than three. Circular rollers manufactured out of steel having cross section with diameter 38 mm will be used for providing support and loading points to the specimens. The length of the rollers shall be at least 10 mm more than the width of the test specimen. A total of four rollers shall be used, three out of which shall be capable of rotating along their own axes. The distance between the outer rollers (i.e. span) shall be 3d and the distance between the inner rollers shall be d. The inner rollers shall be equally spaced between the outer rollers, such that the entire system is systematic. The specimen stored in water shall be tested immediately on removal from water; whilst they are still wet. The test specimen shall be placed in the machine correctly centered with the longitudinal axis of the specimen at right Department of Civil Engineering, National Institute of Technology Srinagar

Page 29



angles to the rollers. For moulded specimens, the mould filling direction shall be normal to the direction of loading. The load shall be applied slowly without shock at such a rate as to increase the stress at a rate of .06 + .04 N/cm2 per second.

Calculations:The flexural strength of the specimen is calculated from the following formula

Flexural strength = Pl/bd2 Where: b = width of specimen d = failure point depth L = supported length P =max. Load

Figure 28:Testing of beam


Page 30



Figure 29: Unmodified Jute

Figure 30: Chemically modified Jute


Page 31



Figure 31: Preperation of jute slurry

Figure 32:Mixing of slurry with cement-sand


Page 32



Figure 33:Casting of Cubes

Figure 34:Vibration and compaction


Page 33



Figure 35: Testing of cube

Figure 36: Cracks due to loading


Page 34



Figure 37: Testing of beam

Figure 38: Recording data


Page 35



Figure 39: Crcaks after loading

Figure 40: Jute bonded with cement-sand


Page 36


Observation and Results

Chapter 05 Observation and Results


Page 37



Table 4:Compressive strength and bending strength of cubes and beams

SAMPLE

DATE OF CASTING

WEIGHT OF SAMPLE (Kg)

STAGE OF STRENGTH (Days)

CODE FOR SAMPLE

FAILURE LOAD (KNs)

STRENGTH (MPa)

CUBIC BLOCK 150 x 150 x 150 MM

23/04/2015

6.85

7

14

21

28

MS1

170

7.55


23/04/2015

6.85

7

14

21

28

MS2

180

8.0


04/05/2015

6.85

7

14

21

28

MS1’

110

4.9

BEAM 100 x 100 x 500 MM

23/04/2015

10

7

14

21

28

MS3

10

4

BEAM 100 x 100 x 500 MM

04/05/2015

10

7

14

21

28

MS3’

9

3.6

BEAM 100 x 100 x 500 MM

29/04/2015

10

7

14

21

28

MS4

9

3.6


01/05/2015

6.35

7

14

21

28

0.25%

130

5.9


01/05/2015

6.25

7

14

21

28

0.25%

207

9.2


01/05/2015

6.35

7

14

21

28

0.5%

140

6.15


01/05/2015

6.25

7

14

21

28

0.5%

215

9.52


01/05/2015

6.35

7

14

21

28

1.0%

135

6.05


01/05/2015

6.25

7

14

21

28

1.0%

210

9.3


Page 38



Table 5:Compressive strength and flexural strength of cubes

SAMPLE

DATE OF CASTING



CODE FOR SAMPLE

FAILURE LOAD (KNs)

STRENGTH (MPa)


05/05/2015

6.3

7

14

21

28

11

140

6.35


05/05/2015

6.25

7

14

21

28

11

210

9.3


05/05/2015

6.25

7

14

21

28

12

145

6.4


05/05/2015

6.25

7

14

21

28

12

230

10.12


05/05/2015

6.25

7

14

21

28

13

155

6.77


05/05/2015

6.2

7

14

21

28

13

235

10.41


05/05/2015

6.3

7

14

21

28

21

150

6.57


05/05/2015

6.25

7

14

21

28

21

230

10.1


05/05/2015

6.3

7

14

21

28

22

150

6.65


05/05/2015

6.3

7

14

21

28

22

235

10.26


05/05/2015

6.2

7

14

21

28

23

155

6.9


05/05/2015

6.2

7

14

21

28

23

240

10.71


Page 39



Table 6: Compressive strength and bending strength of cubes and beams

SAMPLE

DATE OF CASTING



CODE FOR SAMPLE

FAILURE LOAD KNs

STRENGTH MPa


06/05/2015

6.25

7

14

21

31

140

6.35


06/05/2015

6.25

7

14

21

28

31

220

9.82


06/05/2015

6.2

7

14

21

28

32

150

6.7


06/05/2015

6.2

7

14

21

28

32

230

10.26


06/05/2015

6.1

7

14

21

28

33

155

6.85


06/05/2015

6.2

7

14

21

28

33

235

10.56

BEAM 100 x 100 x 500 MM

06/05/2015

9.5

7

14

21

28

0.8%

12

4.8

BEAM 100 x 100 x 500 MM

06/05/2015

9.4

7

14

21

28

0.8%

14.5

5.8

BEAM 100 x 100 x 500 MM

06/05/2015

9.4

7

14

21

28

1.0%

12.5

5

BEAM 100 x 100 x 500 MM

06/05/2015

9.3

7

14

21

28

1.0%

15.5

6.2

BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM

06/05/2015

9.4

7

14

21

28

1.2%

12

4.8

06/05/2015

9.3

7

14

21

28

1.2%

15

6


Page 40



Table 7: Composition of cubes and beams

SAMPLE CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM


SAMPLE CODE

COMPOSITION

6.85

MS1

1:3 cement mortar mix without the reinforcement chemically modified jute

6.85

MS2


6.85

MS1’


10

MS3


10

MS3’


10

MS4

6.35

0.25%

6.25

0.25%

6.35

0.5%

6.25

0.5%

6.35

1.0%

6.25

1.0%

1:3 cement mortar mix without the reinforcement chemically modified jute 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt./vol. sol. Of NaOH 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 1.0% wt. /vol. sol. Of NaOH 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 1.0% wt. /vol. sol. Of NaOH


Page 41



Table 8:Composition of cubes and beams

SAMPLE

CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM


SAMPLE CODE

6.3

11

6.25

11

6.25

12

6.25

12

6.25

13

6.2

13

6.3

21

6.25

21

6.3

22

6.3

6.2

6.2

COMPOSITION

1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 0.25% vol./vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 0.25% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 0.5% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 0.5% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 1.0% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.25% wt. /vol. sol. Of NaOH and 1.0% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH and 0.25% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH and 0.25% vol. /vol. sol. Of Polymer Latex 1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH and 0.5% vol. /vol. sol. Of Polymer Latex

22

1:3 cement mortar mix with the reinforcement of 1% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH and 0.5% vol. /vol. sol. Of Polymer Latex

23


23



Page 42



Table 9: Composition of beams and cubes

SAMPLE


CODE FOR SAMPLE

COMPOSITION


6.25

31



6.25

31


32


32


33


33


0.8%

1:3 cement mortar mix with the reinforcement of 0.8% jute by weight treated with 0.5% wt. /vol. sol. Of NaOH and 1.0% vol. /vol. sol. Of Polymer Latex

0.8%


1.0%


1.0%


1.2%


1.2%


CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM CUBIC BLOCK 150 x 150 x 150 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM BEAM 100 x 100 x 500 MM

6.2

6.2

6.1

6.2

9.5

9.4

9.4

9.3

9.4

9.3


Page 43


Graphical Interpretation of Results

Chapter 06 Graphical Interpretation of Results

Compressive strength vs Samples treated with different wt./vol. solutions of NaOH

14 Days Compressive Strength

7 6

1% jute

5

h t g n e r t s e a P v i s s M e r p m o c

4

1% jute

1% jute

0.50%

1%

0% jute

3 2 1 0 0

0.25%

JUTE treated with different wt./vol. solutions of NaOH only (SAMPLES)

Graph 1: Jute treated with 0.25%, 0.5%, 1.0% wt. /vol. solutions of NaOH solutions only

14 Days Compressive Strength 8 7 h t g n e r t s e a P v i s s M e r p m o C

6

1% jute

1%jute

11

12

1 %jute

5 4

0% jute

3 2 1 0 MS1'

13

SAMPLES Graph 2: Jute treated with 0.25% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol


Page 44



14 Days Compressive Strength 8 7 6

h t g n e r t S e a P v i s s M e r p m o C

1% jute

1% jute

21

22

1% jute

5 4

0% jute

3 2 1 0 MS1'

23

SAMPLES Graph 3: Jute treated with 0.5% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol

14 Days Compressive Strength 8 7 h t g n e r t s e a P v i s s M e r p m o C

6

1% jute

1% jute

1% jute

32

33

5 0% jute 4 3 2 1 0 MS1'

31 SAMPLES

Graph 4:Jute treated with 0.1% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol


Page 45



14 Days Flexural Strength 6

5 1%jute

0.8% jute h t g n e r t a S l P a r M u x e l F

1.2%jute

4 0% jute

3

2

1

0 MS4

0.80%

1%

1.20%

SAMPLES

Graph 5: Jute treated with 0.1% wt. /vol. solution of NaOH and then treated with 0.1% vol. /vol. solutions of polymer

14-DAYS WEIGHT OF BEAMS PRIOR TO TESTING 10.1 10 9.9

0% JUTE

9.8 T H ) G I g K E ( W

9.7 9.6 9.5 9.4 9.3

0.8% JUTE

1% JUTE

1.2% JUTE

0.8%

1.0%

1.2%

9.2 9.1 MS4

SAMPLES



Page 46



14-DAYS WEIGHT OF CUBIC BLOCKS PRIOR TO TESTING 7

6.8 0% JUTE 6.6 T H ) 6.4 G I g K E ( W

1% JUTE1% JUTE1% JUTE 1% JUTE 1% JUTE1% JUTE 1% JUTE1% JUTE 1% JUTE 1% JUTE 1% JUTE

6.2

1% JUTE

6

5.8 5.6 MS1'

0.25% 0.50%

1%

11

12

13

21

22

23

31

32

33

SAMPLES Graph 7: Jute treated with 0.25%, 0.5%, 1.0% wt. /vol. solution of NaOH and then treated with 0.25%, 0.5%, 1.0% vol. /vol. solutions of polymer

28 Days Compressive Strength 10 9

1% jute

1% jute

1% jute

0.50%

1%

8 h t g n e r t s e a v P i s s M e r p m o c

7

0% jute

6 5 4 3 2 1 0 0

0.25%

JUTE treated with different wt./vol. solutions of NaOH wt./vol.

Graph 8: Jute treated with 0.25%, 0.5%, 1.0% wt. /vol. solutions of NaOH solutions only


Page 47



28 Days Compressive Strength 12 10 1%jute h t g n e r t s e a P v i s s M e r p m o C

1 %jute

1% jute

8 0% jute 6 4 2 0 MS2

11

12

13

SAMPLES Graph 9: Jute treated with 0.25% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol.

28 Days Compressive Strength 12 10 h t g n e r t S e a P v i s s M e r p m o C

1% jute

1% jute

21

22

1% jute

8 0% jute 6 4 2 0 MS1

23

SAMPLES

Graph 10: Jute treated with 0.5% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol


Page 48



28 Days Compressive Strength 12

10 h t g n e r t s e a P v i s s M e r p m o C

1%jute

1% jute

1 %jute

8 0% jute 6

4

2

0 MS2

31

32

33

SAMPLES Graph 11: Jute treated with 0.1% wt. /vol. solution of NaOH and then treated with different solutions of polymer 0.25%, 0.5%, 1.0% vol. /vol.

28 Days Flexural Strength 7 6

1%jute 0.8% jute

1.2%jute

5 h t g n e r t a S l P a r M u x e l F

4 0% jute 3 2 1 0 MS3

0.8%

1%

1.2%

SAMPLES



Page 49



28-DAYS WEIGHT OF BEAMS PRIOR TO TESTING 10.2 10 0% JUTE 9.8 T H ) G I g K E ( W

9.6 9.4 0.8% JUTE 9.2

1% JUTE

1.2% JUTE

1%

1.2%

9 8.8 MS3

0.8% SAMPLES


7 6.8

28-DAYS WEIGHT OF CUBIC BLOCKS PRIOR TO TESTING 0% JUTE

6.6 T 6.4 H ) G g I K E ( W6.2

1% JUTE 1% JUTE1% JUTE1% JUTE1% JUTE1% JUTE 1% JUTE 1% JUTE 1% JUTE 1% JUTE 1% JUTE 1% JUTE

6 5.8 5.6 MS1

0.25% 0.50%

1%

11

12

13 21 SAMPLES

22

23

31

32

33

Graph 14: Jute treated with 0.25%, 0.5%, 1.0% wt. /vol. solution of NaOH and then treated with 0.25%, 0.5%, 1.0% vol. /vol. solutions of polymer


Page 50


Discussion

Chapter 07 Discussion

Construction industry is revolutionised by new emerging trends and technology. Jute mortar is one of the new advanced technology but with little knowledge and experimental data. It is because of this that Jute mortar is not being so regularly and at large scale .Jute mortar can be used with traditional building techniques thus using renewable resource at less cost that too with good strength. New technology methods in cement industry results in new machinery and expertise, jute mortar on other hand uses basis raw material easily available and at cheap cost. Concrete structures are structures predominantly made of cement, which is a hydraulic material that hydrates with water to generate a stable material. This hydration reaction produces an amount of calcium hydroxide equivalent to about one third of an amount of cement. Calcium hydroxide is a strong alkali having a pH of about 12 to 13, and forms a passive film on a rebar embedded in the concrete structures to prevent rebar corrosion, thereby maintaining the strength of the concrete structures. However, the nature of concrete structures causes hairline cracks to form during initial curing. When water permeates into the cracks, the cracks in the concrete structures may grow by the repetition of freezing and melting of water depending on changes in temperature, which may remarkably reduce the durability of the concrete structures. Particularly, when airborne salinity or an acidic substance such as carbon dioxide increasing in its level due to air pollution permeates into the concrete structures, the concrete structures may suffer from chloride-induced corrosion and carbonation. The corrosion may be accelerated by the rebar embedded in the concrete structures to maintain the strength of the concrete structures. In other words, when an acidic substance reacts with hydrate in concrete, in particular calcium hydroxide, the pH value of the concrete structures reduces below 10, accompanied by the breakdown of the passive film on the rebar, which causes the concrete structures to deteriorate by the likes of the rebar corrosion. By the rebar corrosion, the volume increases, which then applies tension to the surface of the concrete structures. Hence, the cracks on the surface of the concrete structures may grow to reduce the strength of the concrete structures. Concrete deterioration may progress under physical and chemical environment. Accordingly, extensive repair is needed. To repair concrete, a variety of repair compositions have been used. Among them, there is


Page 51


Discussion

cement mortar including an aggregate such as silic a sand, a binder such as cement, and a fiber reinforcement such as glass fiber or carbon fiber. However, cement mortar has disadvantages of cracking during initial curing or delamination caused by poor bonding at the interface. One of the most common defects that occur when repairing concrete is a defect generated at the interface between new concrete and deteriorated old concrete while curing since old dry concrete absorbs the moisture of fresh concrete after pouring, plastering, and spray coating. This causes a false-set problem, that is, rapid hardening of cement whereby cement just exists in the form of loose powder, failing to serve as a binder. As a result, a reduction in the interfacial bond between new concrete and old concrete leads to reduced bond strength, construction defects such as delamination, and the like. Jute fiber is a hydrophilic natural cellulose fiber, and has excellent dispersion when mixing, thereby avoiding fiber agglomeration caused by the separation of materials when repairing concrete. Also, jute fiber has larger surface roughness and consequently better reinforcing performance than hydrophobic man-made fiber conventionally used in the art. The man-made fiber as a conventional reinforcement has smooth surface and consequently low binding performance, resulting in fiber pull-out from the matrix of the concrete repair composition. As a result, the bond strength at the interface between fresh concrete and old concrete reduces. It is obvious that a man-made fiber may be used together with jute fiber to improve the binding performance and the reinforcing performance such as strength. Jute fiber has high moisture holding capacity to prevent defect generation at the interface between fresh concrete and old concrete during curing that commonly occurs when repairing concrete. As described above, when a hydrophilic man-made fiber is used for reinforcement as conventionally used, old dry concrete absorbs the moisture of fresh concrete. This causes a false-set problem, that is, rapid hardening of cement whereby cement just exists in the form of loose powder, failing to serve as a binder. As a result, a reduction in the interfacial bond between new concrete and old concrete leads to reduced bond strength, construction defects such as delamination, and the like. Jute fiber absorbs a large amount of water during mixing and then provides the water to the concrete to keep it moist during curing, thereby imparting good curing characteristics .Jute fiber used for reinforcement has an average length of 6 cm. The test results confirm that these ranges lead to excellent dispersion and workability. Besides jute fiber, the concrete repair composition includes, as a base component, an aggregate such as silica sand and a binder such as cement, and after mixing with water, may be used in repairing concrete in accordance with conventional methods.


Page 52


Discussion

Application of chemically modified Jute reinforced concrete

1) Jute fiber reinforced cement concrete for precast non-pressure (NP) sewerage pipes. Preparation of concrete for pipe fabrication According to IS 458, 35 M graded concrete is required for fabrication of NP pipe. The

calculated mix design to prepare 35 M concrete is cement: sand: stone chips: 1: 1.5: 2.7, however, here stone chips of two different sizes (20 and 12.5 mm) were used in 70: 30 ratio. The water cement ratio for concrete preparation was 0.4 - 0.42 and the slump value was 25 ± 5 mm. For each set of concrete composites 1% jute fiber was incorporated. Fabrication of jute fiber reinforced concrete pipe (NP3):

Jute reinforced mortar can be used in making fiber reinforced concrete pipe. These pipes have being used in many construction works and have proved their strength and work. Various tests are being conducted and have successfully came out with good results. In two tests which were conducted by a company hydrostatic test of concrete sewerage pipe and second one is the three edge bearing test.

Figure 41: Fabrication of chemically modified jute fiber reinforced precast concrete pipe

Concrete pipes with and without modified jute fiber reinforcement

Concrete pipes with modified jute fiber reinforcement have performed much better than unmodified jute concrete pipes. Due In various places all over the world such pipes are being used .Jute fiber reinforced precast concrete pipes have achieved better properties than that of


Page 53


Discussion

standard pipe. The chemically modified jute fiber reinforced concrete pipe achieves higher strength than that of conventional concrete pipe by incorporating only 20.5 kg of steel cage instead of 29.9 kg. Thus, the chemically modified jute fiber reinforced concrete pipe is cost effective as well as strong. Jute fiber reinforcement in concrete pipe leads to 3.4% increment in load required to produce 0.25 mm crack. Jute fiber reinforcement in concrete pipe leads to 8.4% increment in ultimate load. Pressure was gradually raised upto 0.07 MPa and held for 186 s. No formation of water beads or leakage was found on the surface of pipe.

Figure 42: (a) Pipes without jute fiber reinforcement, (b) Pipes with untreated jute fiber reinforcement, (c) Pipes with chemically modified jute fiber reinforcement

Figure 43: (a)Hydrostatic testing of pipes (b) Three edge bearing test of pipes

2) Jute fiber reinforced cement concrete for prestressed electric poles. Preparation of concrete composites for pole fabrication

According to IS 1678, 45 M graded concrete is required for fabrication of pole. The calculated mix design to prepare 45 M concrete is cement: sand: stone chips (12.5 mm) :: 1: 1: 2. The cement used for pole preparation is OPC of 43 grade. The water cement ratio for concrete preparation was 0.32-0.34. For each set of concrete composites 1% jute fiber was incorporated. When polymer latex modified jute fibers are incorporated into cement matrix, the initial and final setting time is decreased than that of the raw jute fiber reinforced cement. But addition Department of Civil Engineering, National Institute of Technology Srinagar

Page 54


Discussion

of organic admixture (tannin) delays the setting time of cement paste. As the jute fiber percent in cement matrix increases, the initial and final setting times of cement paste increase. The standard test of concrete electric pole is cantilever test. jute fiber reinforced prestressed concrete pole achieved better mechanical properties than that of the standard pole. The chemically modified jute fiber reinforced concrete pole shows higher deflection property than that of conventional concrete pole. Thus, the chemically modified jute fiber reinforced concrete pole can be used in coastal areas.

Figure 44: Fabrication of chemically modified jute fiber reinforced prestressed concrete pole


Page 55


Discussion

Figure 45: Chemically modified jute fiber reinforced prestressed concrete pole

Figure 46: Cantilever testing of modified jute fiber Reinforced concrete electric pole

Figure 47: Maximum flexibility before failure of modified jute fiber reinforced concrete electric pole


Page 56


Discussion

3) Jute fiber reinforced precast cement concrete for pavers block.

According to IS 15658 for fabrication of concrete pavers 35 M graded concrete is required. The mix design of concrete paver is cement: sand: stone chips: 1: 3: 4. Here the size of stone chips used was 3-6 mm. The water cement ratio for concrete paver preparation was 0.2. For each set of concrete composite 1% jute fiber was incorporated

Figure 48: Fabrication process of chemically modified jute fiber reinforced concrete pavers block

Concrete paver blocks with and without modified jute fiber reinforcement

4) Testing of fabricated jute fiber reinforced concrete pavers blocks.

Jute fiber reinforced concrete blocks show very good results when compressive strength test and flexure strength test are done. Jute fiber reinforced precast concrete paver tiles achieves better properties than that of the control paver tiles without jute. The chemically modified


Page 57


Discussion

jute fiber reinforced concrete paver shows 54 % and 69 % higher compressive and flexural strengths respectively than that of control concrete pavers block.

Figure 49: Compressive test of jute reinforced concrete paver block

Figure 50: Flexural test of jute reinforced concrete paver block


Page 58


Discussion

4) Jute fiber reinforced precast cement fly ash roofing sheet

Cement-fly ash sheet composites were fabricated by reinforcing with chopped jute fibers (5 mm length) and jute felts [300x300 (cm 2)] of 250, 400 and 600 gsm. At first the chopped jute fibers and jute felts are soaked into water for 24 h. For chopped jute fiber reinforced cementfly ash sheet composites the cement and sand ratio should be 1:1.5, 10 to 50% cement with replacement by fly ash and different weight percent of water soaked jute fiber mixed with required amount of water (112.5% w.r.t. cement weight) to make slurry, following the above process. The fresh mix thus obtained should be cast in mould [(300x300x6) mm 3)] under 5 metric ton pressure for 2 h at ambient temperature. After 24 h the samples should be demoulded followed by moisture curing for 28 days. For jute felt reinforced cement-fly ash sheet composites, cement and fly ash (2:3) should be mixed with 112.5% of water w.r.t. cement. The water soaked jute felts should then laminated on both sides by cement-fly ash mixture and was placed in the moulds [300x300x6 (mm 3)] under 5 metric ton pressure for 2 h at ambient temperature. After 24 h the samples should demoulded and moisture cured for 28 days.

Figure 51: Chopped jute fiber reinforced cement-fly ash sheet composites

Figure 52: Jute felt reinforced cement-fly ash sheet composites


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Environmental Impact

Chapter 08 Environmental Impact

Introduction: Influence of eco-friendly material.

This project is oriented on reducing the environmental impact of concrete structures throughout their full life-cycle. The scope of this project is to provide information of concrete with inspiration and tools to implement green measures into concrete structures. There is not only one correct solution to design and build a green concrete structure. This text only gives some minimum but valuable information required in modern world where pollution is expanding its roots that too at faster pace. The applicability of each tool will depend strongly on the local conditions in the place of use. Several green building schemes and labelling systems have been developed around the world and it is noted that this project does not constitute a new green label scheme. However, this project may be used to design schemes where economical criteria is mandatory with little resources .It is important to use a holistic view on how concrete structures and concrete production affect the environment during its complete life-cycle. However, it is recognized that the designers and the constructors of concrete structures are not always in control of all the phases in the full life cycle. For instance the energy performance of a building is strongly depending on the end-user’s behavior, which is often out of reach of the building designer. This makes it difficult and maybe even impossible to design a structure that is environmentally healthy from cradle to cradle. For example in Denmark the energy performance of houses was 2

specified to meet a criterion of maximum 10 litres fuel oil per m in the early l980’s. ln 2008 this criterion is halved and it is expected to be halved again by 2015. Therefore, a house that was built 30 years ago according to state of the art building design principles at that time is considered hopelessly outdated according to today’s energy performance standards and may need significant renovation work .Even though the process of designing green concrete structures is subjected to constantly evolving knowledge, standards, regulations and regional levels of technologies, a Department of Civil Engineering, National Institute of Technology Srinagar

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common willingness to mak e a significant improvement must be adopted. In some regions of the world, a small change of thought (e.g. concrete mix optimization with respect to clinker content) may result in substantial reduction in CO2 emissions at a minor investment level, whilst more complex methodologies (e.g overall structural and thermal mass optimization) will apply in other regions. This project intends to inspire and support concrete structure designers by providing a way to use natural material which is available abundantly that can he applied fully or partially depending on the regional limitations. Once again, the need of a holistic planning of the construction phase must be emphasized after the construction process is commenced, the introduction of alternatives may become hindered by economic barriers. For a civil structure the design for long durability and low maintenance is often the most important parameter to obtain a green structure. How does deterioration of concrete occur under Environmental Effect

Figure 53: deterioration of concrete occur under Environmental Effect


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Environmental Role of Jute

Jute Mortar is more environment friendly then ordinary mortar or concrete. Jute is a natural fiber with numerous environmental advantages. It is an annually renewable resource with a high biomass production per unit land area, and jute products being biodegradable decompose in the soil at the end of product life-cycle. Towards global warming, a concern of much importance in the present world, while the synthetic materials are being considered as the root of many problems, the natural fiber products are proven to be absolutely harmless. Jute is The Jute has many positive impacts on the Environment. It is an environment friendly fiber in many aspects. The fiber is environment friendly and its products are also environment friendly and better than the synthetic fibers. It has others indirect role on the economy by impacting on environment. The green leaf is the source of vegetable and dry leaf enhances the fertility of the land. The root of jute increase the fertility and leaf and root act as pesticide. The stick of jute use as a particle and composite and it reduce the dependency on the wood as a fuel which reduces the deforestation. According to the environmentalist, there should be 25% forest area in a country .As a major renewable resource lingo cellulosic fibers derived from the structural plant tissues are expected to play an important role in environment. The markets for fiber crops, such as abaca, coir, jute and sisal have experienced substantial erosion since the introduction of synthetic fibers. However, niche markets have been maintained and a number of new markets are emerging, such as fiber reinforced composites in automotive industries, building and construction materials, and biodegradable geo-textiles, with the ecological image of cellulosic fibers becoming a driving force for innovation and development. Consequently, the production of fiber crops has a limited impact on the environment. In the post harvest processing steps, the fiber extraction process consumes fossil energy and water, generates biomass waste. In general, comparative studies on the production phase of fiber crops with synthetic products, or glass fibers, indicate that fiber crops provide environmental benefits in terms of reduced CO2 and greenhouse gas emission levels and consumption of fossil energy. The energy and chemicals requirements for fiber pulping processes for the


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production

of

paper,

board

and

cellulosic


fiber products

is,

in

general,

ecologically advantageous, as compared to wood based pulping. Jute's growth cycle is very short, typically 4-6 months, and jute materials can be recycled multiple times: Cradle to Cradle. The hurt (inner core) of jute is high-yield cellulose, making jute an ideal source of material for pseudo-woods and paper production, outperforming forest growth in almost all regards. The carbon footprint is low. Jute is a fast growing field crop with high carbon dioxide (CO2) assimilation rate. Jute plants clean the air by consuming large quantities of CO2, which is the main cause of the greenhouse effect. One hectare of jute plants can consume about 15 tons of CO2 from atmosphere and release about 11 tons of oxygen in the 100 days of the jute-growing season. Studies also show that the CO2 assimilation rate of jute is several times higher than trees. (Inagaki, 2000).The ecological footprint is low. Jute is traditionally farmed, it is grown in similar conditions to organic produce. There is crop rotation, little or no pesticides are used and nothing is genetically modified. The water footprint is low. The global water supply is diminishing. Jute is mainly rain fed unlike cotton (2.5% of the world’s water )


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Conclusion

Chapter 09 Conclusion

This work demonstrated the potentiality of jute fiber as reinforcing agent in cement composites for the use of sewer pipes, prestressed concrete pole, and paver blocks. The entire investigation is summarized below.  Systematic

experimental processes were developed for proper modification of jute

fiber with alkali and polymer.  Chemically

modified jute fiber reinforced cement composites were fabricated,

following a systematic experimental program by considering different experimental parameters like different processes, fiber content by weight %, fiber length, and curing time.  Testing

of jute fiber reinforced cement concrete/mortar composite showed

appreciable improvement in mechanical properties, which encourage fabricating prototype cement concrete/mortar products.  The o

following jute fiber reinforced cement mortar products were developed:

Chemically modified jute fiber reinforced cube of dimensions 150mm x 150mm x 150mm.

o

Chemically modified jute fiber reinforced beam of dimensions 100mm x 100mm x 500mm.

 Successful

trials of fabrication and testing of 150mm x 150mm x 150mm cube and

100mm x 100mm x 100m beam were carried out on Universal Testing Machine (UTM) in structural laboratory.  Compressive

and flexural strengths of chemically treated jute fiber reinforced

cement concrete are improved by 48% and 55% respectively than that of the concrete without jute fiber reinforcement.  Weight

of the chemically modified jute fiber reinforced cement mortar reduces by

5-10% of the weight of cement mortar without jute fiber reinforcement.


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References

Chapter 10 Achievements



Chemical modification of jute fiber improved tensile strength and elongation at break about 41 and 34 % respectively.



Water absorption of jute fiber was reduced to 108 % from 210 % after chemical and polymer treatment.



Technique of short jute fiber (optimum length 4-6 mm) dispersion in concrete/mortar was optimized both in dry and wet basis.



Concrete mixing process was optimized with standard ratios of sand, cement, and water to obtain a cement mortar having adequate workability during casting.



Workability of jute fiber incorporated concrete mix was improved using tannin as admixture.



Critical fiber loading was optimized by fabricating cement concrete with different amounts of jute fiber (0.8-1.2% by weight). Maximum compressive and flexural strength was achieved at 1% fiber loading in cement composite which was about 4 kg per cubic meter concrete and 5.5 kg per cubic meter cement mortar.



Compressive and flexural strengths of chemically treated jute fiber reinforced cement mortar (lab based) were improved by 48 and 55% respectively than that of the cement mortar without jute fiber reinforcement.



Degradation study of jute fiber in cement matrices showed that the rate of degradation of treated jute fibers incorporated in cement paste was very slow whereas in case of untreated jute fibers incorporated in cement paste degraded rapidly with time. Chemically modified jute fiber in cement paste retained 97 % of its strength after 90 days aging duration. Whereas, raw jute fiber in cement paste retained 82% of its strength after 90 days aging.


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References

References 

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Applications - Fiber Reinforced Concrete Association - FRCA www.fiberreinforced.org/pages/applications.aspx Concrete Technology By M.S.Shetty Concrete Technology By P.D.Kulkarni Developments in Strategic Materials and Computational Design V Waltraud M. Kriven Development of Glass/Jute Fibers Reinforced www.hindawi.com/journals/ijms/2013/675264/ Engineering Materials: Research, Applications K.M.Gupta Fibre Reinforced Cementitous Composites Arnon Bentur Fiber Reinforced Concrete www.ce.berkeley.edu/~paulmont/241/fibers.pdf Fiber Reinforced Concrete (FRC) courses.washington.edu/cm425/frc.pdf Fiber Reinforcement of Concrete Structures www.uritc.uri.edu/media/finalreportspdf/536101.pdf High Performance Fiber Reinforced Cement Composites By Gustavo J. Parra-Montesinos, Hans W. Reinhard Jute reinforced Composite Technology www.ijira.org/old_html/jutereinforced.htm Jute - Wikipedia, the free encyclopaedia en.wikipedia.org/wiki/Jute Jute Reinforced Composite Technology - World Jute www.worldjute.com › Diversification Mechanical Behaviour of Jute Fibre Reinforced www.iitg.ernet.in/aimtdr2014/PROCEEDINGS/papers/289.pdf Methods of Curing Concrete - Curing types and Techniques www.aboutcivil.org › ... › Hard Concrete Properties


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Jute Motar.pdf...

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