Experimental Investigation on Flexural Strength of Beam by Partial Replacement of Steel Reinforcemen

IJSTE - International Journal of Science Technology & Engineering | Volume 3 | Issue 12 | June 2017 ISSN (online): 2349-784X

Experimental Investigation on Flexural Strength of Beam by Partial Replacement of Steel Reinforcement by Bamboo Madhu. K. S Assistant Professor Department of Civil Engineering Dayananda Sagar College of Engineering Bengaluru560078, India

P. S. Tejaswini Assistant Professor Department of Civil Engineering Dayananda Sagar College of Engineering Bengaluru560078, India

Poornima. B. K Assistant Professor Department of Civil Engineering Dayananda Sagar College of Engineering Bengaluru560078, India

V. C. Chandrashekar Assistant Professor Department of Civil Engineering Dayananda Sagar College of Engineering Bengaluru560078, India

Abstract The Bamboo is used in both technical as well as non-technical ways. Our ancestors used Bamboo in the construction of the houses.

The Bamboo was used as the struts, posts, roofs etc. in the construction of the houses. Now a day’s concrete are used as the basic materials for the construction works. The concrete is good in compression but weak in the tensile strength. So steel is used as reinforcement in the concrete to achieve the tensile strength. Problems encountered with the commonly used construction material like steel are high in cost, corrosion, etc. Due to the advantageous characteristics of Bamboo, in the last few years, studies have been made on the use of Bamboo as structural material and reinforcement in concrete. The project deals with strength-wise and cost-wise comparison of beam with partial replacement of steel reinforcement by bamboo and beam with conventional tensile reinforcement. The utilization of bamboo reinforcement by replacing steel reinforcement is gaining immense importance today, mainly an account of the improvement in the economical aspect combined with ecological benefits.

Keywords: Bambusa Bamboo, Flexural Strength, Partial Replacement, Tensile Reinforcement, Bamboo Treatment, Bamboo Seasoning ________________________________________________________________________________________________________ I.

INTRODUCTION

Concrete is a widely used construction material for its various advantages such as low cost, availability, fire resistance etc .But it cannot be used alone everywhere because of its low tensile strength. So, generally steel is used to reinforce the concrete. Though steel has a high tensile strength to complement the low tensile strength of concrete, use of steel should be limited since it is very costly and also energy consumption is more in manufacturing process.

Globally, the iron and steel sector is the second largest industrial user of energy, consuming 616 Millions of tons of oil equivalents and the largest industrial source of Carbon dioxide (CO2) emissions. India's iron and steel sector is the largest industrial user of energy in India, consuming 38 million tons of oil equivalents. It is also the largest industrial source of carbon dioxide (CO2) emissions with 151 million tons of CO2.There is urgency need for using naturally occurring products as a construction material to decrease the growth of energy consumption and CO 2emissions, replacement of bamboo in place of steel is widely recognized as one of the most important non-timber forest resources because of the high tensile strength and socio-economic benefits with bamboo based products. Bamboo has been used as a construction material in certain areas for centuries. As a result, many researchers have been trying to find the non-polluting and eco-friendly materials. Recently bamboo was considered to make use as a reinforcement material as it behave in elastically even in light loads. Therefore Bamboo is used as a reinforcing material instead of steel reinforcement in concrete. Bamboo is seismically resisting material and for sustainable environment development without harming our global environment since it absorbs a lot of nitrogen and carbon dioxide from the atmosphere during its growth. Bamboo is a tall grass and fast-growing plant.

The world’s timber demand is increasing at a rapid rate but the timber supply is depleting. It’s been found through research that bamboo can suitably replace timber and other materials in construction and other works. Industrially treated bamboo has shown great potential for production of composite materials and components which are cost-effective and can be successfully utilized for structural and non-structural applications in construction. Bamboo is one of the oldest traditional building materials used by mankind. The bamboo culm or stem has been made into an extended diversity of products ranging from domestic household products to industrial applications. Bamboo is quite common for bridges, scaffolding and housing, but it is usually used as a

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Experimental Investigation on Flexural Strength of Beam by Partial Replacement of Steel Reinforcement by Bamboo (IJSTE/ Volume 3 / Issue 12 / 027)

temporary exterior structural material. In many overly populated regions of the tropics, certain bamboos supply the one suitable material that is sufficiently cheap and plentiful to meet the extensive need for economical housing. With the advancement of science and technology and the tight supply of timber, new methods are needed for the processing of bamboo to make it more durable and more usable in terms of building materials. Studies have been carried out on the basic properties and on processing of bamboo into various kinds of composite products.

II. AIM AND OBJECTIVES    

To study the flexural behavior of the beam.

To compare the flexural strength of the beam with conventional tensile reinforcement and beam with steel reinforcement replaced by bamboo.

To study the flexural behavior of the beam in which tensile reinforcement is partially replaced with bamboo.

To compare the cost of beam with steel reinforcement replaced by bamboo and beam with conventional tensile reinforcement.

III. EXPERIMENTAL INVESTIGATION

Concrete samples were made using ordinary Portland cement using M25 mix design. A mechanical property flexural strength of beams is evaluated. Flexural test was conducted for beams of size150 x 150 x 700 mm with 4 different variations of steel reinforcement replaced by bamboo after 28 days of curing. The four different variations of steel reinforcement replacement by bamboo used for the study are mentioned below:  Case 1: Zero replacement of steel by bamboo  Case 2: 1/3rd replacement of steel by bamboo  Case 3: 2/3rd replacement of steel by bamboo  Case 4: Complete replacement of steel by bamboo Treatment of Bamboo Thermal Modification Heat treatment involves heating bamboo material to a temperature of 180–220 °C while at the same time protecting it with steam.

The steam protects the bamboo, but it also influences the chemical changes taking place in bamboo.

Thermally modified bamboo is an environmentally friendly and fully recyclable product, the manufacture of which does not include any harmful chemicals.

During treatment the cells of bamboo are modified and that causes the changes in bamboo characteristics:  The color darkens, new color is from light brown to very dark brown  Equilibrium moisture content is reduced 20-50%  Increased dimensional stability  Decreased water absorption  Less deformations and tensions caused by humidity changes  Heat conductivity lowered up to 20-30%  Bamboo density decreases  Resin is removed from the bamboo during the thermal modification process Materials used Steel Grade: Fe500 a) Details of Positive reinforcement bars: Length - 650mm, Diameter – 12mm No. of specimens used for the reinforcement:  Case 1: For Zero replacement of steel by bamboo-3  Case 2: For 1/3rd replacement of steel by bamboo -2  Case 3: For 2/3rd replacement of steel by bamboo -1 b) Details of negative reinforcement bars (Anchorage bar):  Length – 650mm  Diameter – 10mm c) Details of Stirrups Length – 100mm, Diameter – 8mm Type of bamboo used: Bambusa Bamboo Length: 650mm Breadth: 21mm Width: 6mm

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Experimental Investigation on Flexural Strength of Beam by Partial Replacement of Steel Reinforcement by Bamboo (IJSTE/ Volume 3 / Issue 12 / 027)

No. of bamboo strips used as reinforcement:  Case 1: For zero replacement of steel by bamboo -0  Case 2: For 1/3rd replacement of steel by bamboo -1  Case 3: For 2/3rd replacement of steel by bamboo – 2  Case 4: For complete replacement of steel by bamboo - 3 d) Properties of Bamboo Specific gravity - 0.575 to 0.655 Average weight - 0.625kg/m Modulus of rupture - 610 to 1600kg/cm2 Modulus of Elasticity - 1.5 to 2.0 x105kg/cm2 Ultimate compressive stress- 794 to 864kg/cm2 Safe working stress in compression - 105kg/cm2 Safe working stress in tension- 160 to 350kg/cm2 Safe working stress in shear- 115 to 180kg/cm2 Bond stress - 5.6kg/cm2  Fine aggregate: zone II from IS 456-2000  Coarse aggregate: angular aggregate of 20mm size  Cement: Ordinary Portland cement of 43 grade was used and tested for physical and chemical properties and found to be conforming to various specifications as per IS: 12269-1987. Specific gravity= 3.15  Test on Beams: Flexural strength test has been carried out in loading frame with 2 point loading condition.

Specimen Details In this Study, 3 beams for each variation of steel reinforcement replacement by bamboo were casted. Totally 12 such beams were tested after 28 days of curing to determine flexural strength. The mix design of concrete was done according to Indian Standard codes for M25 grade concrete. The reinforcement of the beam whose steel reinforcement is replaced by bamboo is shown in Fig 1. Casting of the beams is shown in Fig 2.

Fig. 1: Reinforcement details of the beam

Fig. 2: Casting of beams

IV. RESULTS AND DISCUSSION The Flexural strength of the beams with four different variations of steel reinforcement replacement by bamboo is listed in table 1. Average Flexural strength of the beam with complete steel reinforcement is found to be 13.87 N/mm2 as conducted with reference to Fig 3. In second case i.e, Where 1/3 rd of Steel reinforcement is replaced by bamboo, Average Flexural strength of the beam decreases to 13.81 N/mm2. In third case, When 2/3rd of Steel reinforcement is replaced by bamboo, The average flexural strength of rhe beam is found to be 11.91 N/mm2. Whereas, in fourth case when the complete steel reinforcement is replaced by bamboo it was found that the average flexural strength of beam is 10.70 N/mm2. Failure of beam specimen after flexure test is as shown in Fig 4.

Fig. 3: Flexural strength of beam at complete

Fig. 4: Beam test after Flexure test

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Experimental Investigation on Flexural Strength of Beam by Partial Replacement of Steel Reinforcement by Bamboo (IJSTE/ Volume 3 / Issue 12 / 027)

Cases Case 1

Case 2

Case 3

Case 4

Table - 1 Comparative study of ultimate load, deflection and flexural strength of four different cases Trial Ultimate load (KN) Deflection (mm) Flexural strength (N/mm2) Average flexural strength (N/mm2) 1 85.99 2.2 3.821 2 96.76 2.3 4.367 13.87 3 98.36 2.4 4.371 1 85.21 1.79 12.62 2 89.01 1.92 13.18 13.10 3 91.22 1.86 13.51 1 75.66 1.24 11.20 2 85.21 1.32 12.62 11.91 3 80.56 1.45 11.93 1 60.60 0.75 8.97 2 75.30 0.82 11.15 10.70 3 80.90 0.89 11.98

Comparative study of flexural strength of 4 different cases is shown in Fig 5.

Fig. 5: Comparative study of Flexural strength of four different cases

V. CONCLUSION    

From the above discussion, it can be concluded that in the tensile reinforcement of the beam a steel bar can be replaced by a bamboo efficiently to get effective results in the flexural strength of beam.

From the above results, it can be concluded that in the tensile reinforcement of the beam, if a steel bar is replaced by a bamboo, the failure will be followed by a caution and there will not be catastrophic failure of the beam similar to that of beam with conventional tensile reinforcement.

From the tensile test results of steel and bamboo, it can be concluded that replacing steel by bamboo will not affect the stress withstanding capacity of the structure.

From the cost wise comparison, it can be concluded that cost of a bamboo when compared to cost of steel is less and steel can be replaced by bamboo economically.

REFERENCES

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Dr V M Chariar, “Fabrication and Testing of Jute Reinforced Engineered Bamboo Structural Elements.” Centre for Rural Development and Technology Indian Institute of Technology, Delhi .p-ISSN: 320-334X, Volume 8, 2009.

M.D. Kakkad, C.S. Sanghvi, “Comparative Study of Bamboo (Ikra) Housing System with Modern Construction Practices.” Electronic Journal of Geotechnical Engineering (EJGF), 1523-1545, 2011.

H. Sakaray, N.V. Vamsi, “Investigation on properties of bamboo as reinforcing material in concrete.”International journal of engineering research and applications, 77-83, 2012.

Anurag Nayak, Arehant S Bajaj, “Replacement of Steel by Bamboo Reinforcement.” IOSR Journal of Mechanical and Civil Engineering (ISOR-JMCE),eISSN:2278-1684, Volume 8, 2013.

Chandra Sabnani, Madhuwanti Latkaret, “Can Bamboo Replace Steel as Reinforcement in Concrete, for the key Structural Elements in a Low Cost House, Designed for the Urban Poor “International Journal of Chemical, Environmental & Biological Sciences (IJCEBS), ISSN 2320 –4087, Volume 1, 2013.

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