INVESTICATION & FLEXURAL PERFORMANCE ON CONCRETE BEAM USING BAGASSE ASH

INVESTICATION &FLEXURAL PERFORMANCE ON CONCRETE BEAM USING BAGASSE ASH

The utilization of industrial and agricultural waste produced by industrial processes has been the focus of waste reduction research for economical, environmental and technical reasons.  Bagasse ash is fibrous waste product of the sugar refining industry, these industrial wastes affect the surrounding environment and thus we need a good solution for hardly the wastes.

The objective of this work is to evaluate the flexural behaviour of concrete beams using partially replacement of cement with bagasse ash. There different replacement percentage level of 10%, 20% and 30%were used in this study. Out of which 20% was identified optimum replacement level through the testing of control specimens. A total of four beams were cast for the present study. Two beams served as control beam and another two beams was cast with 20% bagasse ash replacement the beams were 125mm X 250mm cross section and 3200mm long. The beams were tested under four point bending over a span of 3000mm.sufficient data was obtained on the strength and deformations characteristics of control beam as well as bagasse ash replaced beam. The study of parameters considered for this study included first crack load, deflection at first crack load, yield load, deflection at yield load, ultimate load and deflection at ultimate load.

Key words: Bagasse Ash, ControlBeams and Mechanical Properties

About The Author:

Sp.Aswinpalaniappan M.E.,*

Member of American Concrete Institute

Sri Raaja Raajan College of Engineering and Technology

Karaikudi, Tamil Nadu 630301

STRENGTHENING OF RC BEAM WITH PREFABRICATED RC PLATE

STRENGTHENING OF RC BEAM WITH PREFABRICATED RC PLATE

In retrofitting of Reinforced concrete (RC) beams which are insufficient in terms of shear and flexural capacities are strengthened by various methods. Steel and fibre reinforced polymer (FRP) plate bonding methods are very widely used in strengthening of beams. Strengthening methods such as bonding steel and FRP plates have deficiencies as corrosion, fire and buckling. In this work, it is aimed to strengthen damaged RC beams using prefabricated RC rectangular plate. The rectangular cross-sectional plates were bonded to the bottom side of the beams by rods and epoxy. The experimental results were compared with the theoretical values. The experimental results were compared with the theoretical values In addition; post-elastic strength enhancement and displacement ductility of beams were investigated. The advantages of this method do not require shuttering, concrete and steel workmanships in situ. Also, the application of this method is very easy and result in reduction in retrofitting cost compared to other methods.

About The Author:

Sp.Aswinpalaniappan M.E.,*

Member of American Concrete Institute

Sri Raaja Raajan College of Engineering and Technology

Karaikudi, Tamil Nadu 630301

CHARACTERISTIC STUDY OF HIGH VOLUME        FLYASH CONCRETE WITH ADDITION OF OPTIMUM % OF COIR AND GLASS FIBER 

The use of concrete containing high volume fly ash has recently gained popularity as a resource efficient , durable and sustainable option for a variety of concrete applications. The addition of natural fibre into fresh concrete can increase the ductility of the concrete matrix. Economic and other related factors in many developing countries where natural fibres are abundant , demand that engineers apply appropriate technology to utilize the natural fibres as effectively and economically as possible. To evaluate the efficiency of coir and glass fibres in improving the properties of the concrete the performance of plain concrete is used as a reference. Compressive strength , modulus of elasticity , split tensile strength , flexural strength , durability tests such as water absorption and acid resistance were determined for all fibre reinforced concrete and plain concrete specimen. The current manuscript deals with subject of addition of natural and artificial fibres to concrete in order to study the strength properties. . The increase in cube compressive strength for fly ash based fiber concrete with respected to the age is generally less than that for plain concrete. The maximum flexural strength obtained for high volume flyash and fibre content 0.15% of coir fiber and 1.5% of glass fiber was 5N/mm2 and that for plain concrete was 2.82N/mm2. The corresponding strength improvement is 43.65%. It is seen that high volume flyash concrete and plain portland cement concrete shared a nearly equal strian value of the point of maximum stress. . The performance of 50% fly ash replaced concrete is better than the plain concrete against acid exposure.SEM provides an excellent technique for examining the surface morphology of fibres. Selective natural waste materials at large are utilized to improve the strength and ductility properties of concrete. From the EDAX spectra recorded, calcium is the main mineral component, but silicon, aluminium and even potassium is well augmented.  

Keywords : Coir fiber , Glass fiber , Compressive strength , Durability   

About The Author:

Sp.Aswinpalaniappan M.E.,*

Member of American Concrete Institute

Sri Raaja Raajan College of Engineering and Technology

Karaikudi, Tamil Nadu 630301

Retrofitting of damaged reinforced concrete beams with a new green cementitious composites material

Retrofitting of damaged reinforced concrete beams with a new green cementitious composites material

Significance Statement

Overloading of concrete structures leads to short lifetime of structure or even collapse during extreme cases. Rehabilitation of damaged concrete structures in order to meet requirements after carrying high permissible load is a better alternative to demolishing and rebuilding due to present economic climate condition.

Ultra-high performance fiber-reinforced cementitious composite UHPFRCC have been successfully applied in retrofitting or strengthening of reinforced concrete beams. CARDIFRC, one of the techniques of UHPFRCC has benefitting features such as tensile strength, stiffness and coefficient of linear thermal expansion which are comparable with that of parent member material.

 However, CARDIFRC requires high cement content which does not enhance concrete properties but increases emission of greenhouse gases contributing to global warming. In order to overcome this problem, a green-USM-reinforced concrete which has lesser cement content (< 360Kg/m³) compared to 744Kg/m³ of CARDIFRC is currently being developed in Universiti Sains Malaysia USM.

Research conducted by Dr. Aldahdooh and colleagues expanded their findings on green-USM-reinforced concrete GUSMRC as a new green retrofitting material. The work published in Composite Structures examined its flexural behaviors such as crack development, crack modes, flexural capacity and deflection capacity of a reinforced concrete before and after retrofitting

Results from crack development in reinforced concrete beams before retrofitting showed that recorded failure load of three beams of G(0) members was between the range of 37KN to 39.68KN and their failure mode was due to diagonal tension. The third beam reached the highest load of 39.68KN (cycle 16).

The beam A-T20-R20KN-B1 was selected with shear tension failure as the worst failure case. The beam failed when load reached the ultimate capacity of 55.25KN (cycle 22). Compared with results of reinforced concrete before retrofitting, the increase in ultimate failure load of the beam reached 41.3%.

Difference between failure load capacity of both GUSMRC and CARDIFRC were insignificant and at 30KN and 40KN, beams retrofitted with CARDIFRC strips were slightly larger than those of beams retrofitted with GUSMRC concrete strips in terms of ratio of mid-span deflection of beams after retrofitting to before retrofitting

This study proves that GUSMRC can effectively serve as a good retrofitting material.     

Figure Legend :Procedures for bonding the retrofitting GUSMRC strips.
       (a)1^st step                                                          (b) 2^nd step 

  


(C) Last step for this type of retrofitting



(d) Last step for this type of retrofitting
Figure Legend 2: Casting of GUSMRC strips for retrofitting


Figure Legend 3: Steel fiber distribution inside GUSMRC strips

Thanks to 

About The Author

Majed A. A. Aldahdooh was born in Palestine in 1987. He received the B.Sc. degree in civil engineering from the Islamic University of Gaza (IUG), in 2009, the M.Sc. & Ph.D. degrees in structural engineering from the Universiti Sains Malaysia (USM), in 2011 and 2014. Respectively. He is currently an Assistant Professor at the University of Buraimi, Sultanate of Oman.

His main areas of research interest are structural design, structural retrofitting, concrete technology and structural health monitoring. Along with his experience in teaching and research; he has several awards including the Ph.D. Fellowship from the USM (2011-2014), the best Ph.D. research award from the USM (2014) and several awards for the excellent achievement in journal publications with high impact factor.

About The Author

Norazura Muhamad Bunnori (PhD) has been involved in Acoustic Emission (AE) technique and concrete technologies since 2004 while she was pursuing her PhD study at Cardiff University, Wales, UK. She was graduated from Cardiff University in 2008 and continues with the AE and concrete research areas at Universiti Sains Malaysia (USM), Malaysia. Currently she is working as an Associate Professor at School of Civil Engineering, USM since 2009.

The research covered several topics of AE applications and analysis (quantitative and qualitive) and concrete technologies. The aims are to continue the AE study especially in Structural Health Monitoring (SHM) and concrete technologies research areas and to discover more in these potential areas. The passion towards AE and concrete are deep and she believes that there are a great number of information can be studied and discovered. 

About The Author

Dr. Megat Johari is presently a professor at the School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia 14300 Nibong Tebal, Pulau Pinang, Malaysia. He specializes in Concrete Materials and Technology. He has been teaching Concrete Technology, Civil Engineering Materials, Construction Technology and Structural Retrofitting Technology courses.

He obtained his PhD and MSc (Eng) degrees from Leeds University in 2001 and 1996, respectively, and BSc degree from Ohio Northern University in 1990. He has successfully supervised and co-supervised more than twenty Master and Phd students, where many of them were international students. He has authored and co-authored more than 70 papers, which have been published in refereed journals and proceedings. The published papers have received more than 700 citation based on scopus.

He has served as manuscript reviewer for many international journal such as Construction and Building Materials, Cement and Concrete Research, Materials and Structures, Journal of Hazardous Materials, International Journal of Environment and Waste Management, Journal of Thermal Analysis and Calorimetry, Journal of Civil Engineering and Management and a few other international journals.

Dr. Megat Johari is currently serving as editorial board member for Malaysian Construction Research Journal and Journal of Civil Engineering, Science and Technology. He has been actively involved as speaker in seminars and short courses related to concrete durability, assessment, maintenance as well as repair and strengthening. Besides, he has undertaken many testing and consultancy works related to evaluation of concrete in existing structures.

About The Author

Ali S. Alnuaimi, Associate Professor in Civil and Architecture Engineering Department, Sultan Qaboos University, Oman. Dr. Ali earned his Ph.D. from Glasgow University, UK and his M.Sc. from University of Southern California, USA.

His research expertise focuses on structural design and analysis and estimating construction cost. He published more than 42 refereed journal papers and 33 conference papers. He supervised/co-supervised more than 30 BSc, 10 MSc and 3 PhD research projects. Dr. Ali has vast industrial experience as civil and structural engineer as well as director of projects and maintenance. 

About The Author

Ahmad Jamrah is a full professor of civil and environmental engineering with the Department of Civil Engineering, University of Jordan in Amman, Jordan. Dr Jamrah is currently the Dean of the College of Engineering at the University of Buraimi in the Sultanate of Oman. Dr Jamrah teaches and conducts research the areas of civil and environmental engineering. 

Journal Reference
Majed. A.A. Aldahdooh¹ ,  Muhamad Bunnori², A. Megat Johari², Ahmad Jamrah¹, Ali Alnuaimi³. Retrofitting of damaged reinforced concrete beams with a new green cementitious composites material,  Composite Structures, Volume 142,  2016, Pages 27–34.

Sustainable Concrete - An Inevitable Need for Present & Future

Concrete has become, by far, the most widely used construction material in the world. It is surpassed only by water as the most used material on earth. Concrete is perceived and identified as the provider of a nation’s infrastructure and indirectly of its economic progress and stability, and indeed, of the quality of life of the people. Concrete is easily and readily prepared and fabricated in all sorts of conceivable shapes and structural systems for application in infrastructure, habitation, transportation, work and play. Its simplicity lies in its constituents that are readily available anywhere in the world.

When a material becomes as integral to the structure as concrete, it is important to analyse its environmental impact to conclude if the material is as sustainable as it is prevalent. If the material does not satisfy the credential of sustainability, it should be a matter of concern, especially today when people and authorities are more conscious environmentally.

In 1987, the World Commission on Environment and development defined sustainable development as Development that meets the needs of the present without compromising the ability of future generations to meet their needs, and later on at the 1992 Earth Summit in Rio de Janeiro as economic activity that is in harmony with the earth’s ecosystem.

As a matter of fact, concrete related activities consume gigantic quantum of non-renewable resources both in direct and indirect manner. It is dis-heartening to hear that corrosion of steel in concrete shrinks the life span and serviceability of large number of structures. A huge sum of national wealth is spent for repairs and rehabilitation of concrete structures. Ever increasing problem of early aging & short life cycle of concrete structures has been adding to the huge volume of restoration, repair & rehabilitation works. Additionally, high volume of structural repair works consume huge quantum of non-renewable resources. Thus, to make concrete and built structures sustainable one has to make it more durable and more emphasis has to be given to the durability right from the designing stage of the structures.

Important goals of a concrete structure:

1. Safety
2. Economy
3. Durability
4. Sustainability

Safety, Economy and Sustainability are functions of Durability. Hence, achievement of Durability is most critical and important in concrete construction.

Durability: A durable concrete structure is one that performs satisfactorily in the working environment during its anticipated exposure conditions during service (IS 456-2000).

Durability depends on two main factors:

1. The concrete system &
2. The service environment

1. Concrete system is based on
   • Quality and quantity of materials used and
   • Processes involved in manufac- ture of concrete.
2. Service environment affects concrete by way of-
   • Physical actions and
   • Chemical action on concrete.

Quality of ingredients of concrete impact the strength and durability. Nowadays, blended cement or concrete with mineral admixtures are preferred for construction and by structural engineers. Blended cement not only has an edge over OPC as far as high performance or durablity is concerned, but has environmental benefits as well. It is a well-known fact that in manufacturing of 1 MT of cement nearly I MT of CO2 is emitted in the environment. By choosing PPC or PSC in construction, we are not only using our limestone (natural resource) but utilizing waste of thermal & steel plants (fly ash & slag) and converting it in to wealth.

Permeability of concrete plays an important role in durability because it controls the rate of entry of moisture that may contain aggressive chemicals and the movement of water during heating or freezing. Higher the permeability lesser will be the durability.

It can be seen in the figure below that one of the most common and serious causes of deterioration of concrete is corrosion of reinforcement and permeability is an important cause of it among others.

The way forward

• Blended cements like PPC and PSC have been well accepted in the country. However, we need to improve the percentage of fly ash and GGBS content in our cement and concrete.
• We may have Indian Standards for pozzolanic cement with up to 50% replacement of OPC by fly ash for high volume fly ash concrete roads and other applications.
• We need to have positive support from the authorities in this endeavour for sustainable construction.
• We have to encourage use of micro fine products like silica fume or micro silica, etc. for producing impermeable, high strength and super high strength concrete to assist in building more with less, with savings of about 50% of concrete volume.
• We need to increase use of classified fly ash by processing fly ash into different categories based on its fineness so that it can contribute effectively in producing very high strength as well as normal strength and durable concrete with lower cement utilization.
• Recycling of concrete from C&D wastes.
• More responsible and professional approach in designing and execution of work (effective workmanship).

Conclusion

Basic concept of sustainable construction is conserving the natural resources for future generation, by conserving virgin materials and protecting the environment by reducing, re-using and recycling the waste and reducing CO2 emission.

Indian Cement, Concrete and Construction industry has made substantial contribution in sustainable construction. However, there is a long way to go and we are able to build more with less (by increasing use of ultra-high strength concrete). The day we consume our entire industrial by-products like fly ash, blast furnace slag, etc., we can claim that we have really contributed to the nation and to the world at large.
 

Thanks to 

Ratan Kumar Jha, Zonal Head- Customer Technical services, JK Cement Limited, New DelhT

Types of Concrete

Concrete, a widely used building material in the world. I can’t imagine any civil construction without concrete. There are many types of concrete are used in the sector.

• Normal-strength concrete
• Light-weight concrete
• Air entrained concrete
• High-Strength concrete
• High performance concrete
• Self-consolidated concrete
• Shotcrete
• Pervious concrete

a

Normal-strength concrete 
This type of concrete is produced by mixing basic concrete ingredients. Strength of it varies between 10 MPa to 40 MPa. The initial setting-time is 30 to 90 minutes depending on “cement properties” and weather condition.

Light-weight concrete 
The unit weight of this type of concrete is less than the concrete made of basic ingredients. Normally unit weight varies from 240 kg/m3 to 1850 kg/m3. The strength of light-weight is 7 MPa to 40 MPa. 
 
Air entrained concrete
Air entrained concrete is the fabulous invention in concrete technology. It is produced by mixing air entraining admixture with normal concrete. The strength of this concrete type is lower than normal concrete.

High-Strength concrete
This type of concrete is produced by selecting high quality aggregate, lowering w/c ratio and mixing admixture to concrete. The strength of this, is about 6000 psi.

High performance concrete 
This special type of concrete strength can be 10000 psi to 15000 psi. That mean, it is super high strength. And it’s also high durable.

Self-consolidated concrete
Its name describe about it. This doesn’t need any vibration for compacting. It’s compacted by its own weight. That’s why it’s also called self-compacting concrete. It has the high workability which is measured 650-750 mm on a flow table. That’s the reason for its another name, flowing concrete.

Shotcrete concrete
This concrete is applied onto structure or into frame by shooting with a nozzle. This technology uses compressed air to shoot. In this concrete application, placing and compaction undergo at same time due to air force.

Pervious concrete 
This concrete contains 15% to 20% voids of its volume when set. These voids allow water to pass through it.

Concrete can be various types depending on mixing process, application methods, mixing compositions, characteristic, performance etc. But the types of concrete, I discussed in this article, is n’t based on any specific purpose. Those are the common types of concrete.

About The Author:

Sp.Aswinpalaniappan M.E.,*

Member of American Concrete Institute

Sri Raaja Raajan College of Engineering and Technology

Karaikudi, Tamil Nadu 630301