IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Study on the mechanical properties and fracture behavior of chopped steel fib...eSAT Journals
Abstract
Fiber reinforced concrete (FRC) is widely practiced with high ductility and sufficient durability. In this study, the properties of the
volume fraction and length of steelfiber (SF) on the mechanical properties of FRC were analyzed. This paper provides result data
of the compressive strength, and split tensile strength, flexural strength of steel fiber reinforced concrete. The variables in this
study the percentage of volume fraction (0, 1.0, 1.5, 2, 2.5 & 3) of steel fibersby weight of total weight of concrete. For
compression test, a result data obtained has been analyzed and related with a control specimen (0% fiber). A relationship
between Compressive strength vs. fiber volume fraction and tensile strength vs. fiber volume fraction & flexural strength vs. fiber
volume fraction of steel fiber are represented graphically. The addition of fiber enhanced the ductility significantly. Result data
clearly shows a small increase in compressive strength for M30 Grade of concrete due to addition of 0.1% steel fiber, but for
0.2% addition a marginally increase in strength after that the strength is decreased.
Key words: self-compacting concrete, steel fiber, mechanical properties, volume fraction, fracture energy
Statistical modeling to forecast the strength of concrete using accelerated c...eSAT Journals
Abstract It is very much necessary to know the performance of the concrete mix before their actual use on site. The fact that all the required readings of concrete are only obtained after 28 days of curing which becomes a constraint when various grades of concrete are to be used in the same work. Accelerated curing of concrete is a good solution in such cases. IS 9013-1978 gives detailed description as well as guidelines to be adopted during the process of accelerated curing along with an equation to predict the 28 days strength of the concrete. An equation which predicts the achievable strength of concrete under normal curing by using the accelerated curing strength as the dependent parameter is available in the IS code. In this paper we have analyzed the reliability of the equation when additives such as fly ash are used in the mix. At the end it was found that the predicted values largely varied from the actual values obtained from the IS code. In this paper an effort is made to form a new equation by using 3 independent variables such as the fly ash content, water-cement ratio and the accelerated curing strength to obtain fairly reliable results. Key Words: Statistical modelling, Regression, Strength of concrete, Accelerated curing, fly ash
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study on the mechanical properties and fracture behavior of chopped steel fib...eSAT Journals
Abstract
Fiber reinforced concrete (FRC) is widely practiced with high ductility and sufficient durability. In this study, the properties of the
volume fraction and length of steelfiber (SF) on the mechanical properties of FRC were analyzed. This paper provides result data
of the compressive strength, and split tensile strength, flexural strength of steel fiber reinforced concrete. The variables in this
study the percentage of volume fraction (0, 1.0, 1.5, 2, 2.5 & 3) of steel fibersby weight of total weight of concrete. For
compression test, a result data obtained has been analyzed and related with a control specimen (0% fiber). A relationship
between Compressive strength vs. fiber volume fraction and tensile strength vs. fiber volume fraction & flexural strength vs. fiber
volume fraction of steel fiber are represented graphically. The addition of fiber enhanced the ductility significantly. Result data
clearly shows a small increase in compressive strength for M30 Grade of concrete due to addition of 0.1% steel fiber, but for
0.2% addition a marginally increase in strength after that the strength is decreased.
Key words: self-compacting concrete, steel fiber, mechanical properties, volume fraction, fracture energy
Statistical modeling to forecast the strength of concrete using accelerated c...eSAT Journals
Abstract It is very much necessary to know the performance of the concrete mix before their actual use on site. The fact that all the required readings of concrete are only obtained after 28 days of curing which becomes a constraint when various grades of concrete are to be used in the same work. Accelerated curing of concrete is a good solution in such cases. IS 9013-1978 gives detailed description as well as guidelines to be adopted during the process of accelerated curing along with an equation to predict the 28 days strength of the concrete. An equation which predicts the achievable strength of concrete under normal curing by using the accelerated curing strength as the dependent parameter is available in the IS code. In this paper we have analyzed the reliability of the equation when additives such as fly ash are used in the mix. At the end it was found that the predicted values largely varied from the actual values obtained from the IS code. In this paper an effort is made to form a new equation by using 3 independent variables such as the fly ash content, water-cement ratio and the accelerated curing strength to obtain fairly reliable results. Key Words: Statistical modelling, Regression, Strength of concrete, Accelerated curing, fly ash
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Fresh and Hardened Properties of Ground Granulated Blast Furnace Slag Made Co...IJMREMJournal
This research work was carried out on concrete specimens made with different proportion of Ground Granulated Blast Furnace Slag (GGBFS) as a cement substitution in concrete. To accomplish the goal of the research work, overall 75 cubes and 60 cylinders were made. Out of 75 cubes and 60 cylinders, 15 cubes and 12 cylinders were cast for control concrete, and 60 cubes and 48 cylinders were cast by replacing 5,10,15 and 20% of cement with GGBFS. The cubes and cylinder specimens were 100x100x100 mm and 100x200 mm respectively, and mix design was done for 28 Mpa. All specimens were tested at 3. 7, 28 and 90 days of curing ages. The fresh properties such as workability and hardened properties such as compressive and tensile strength of all mixes were determined. Tests results showed that the workability of the concrete mixes made with GGBFS was higher than control mix. As the percentage of GGBFS increased the workability also increased. Hardened properties of concrete mixes made with GGBFS was lower than control concrete at early ages of curing. At the later age, hardened properties of GGBFS made concrete was more than control concrete. Furthermore, water absorption and density of GGBFS made concrete was lower than control concrete.
Flow time analysis of blended mixes using Marsh cone apparatusAbdulRazakBH
Abstract -Admixture-Cement interaction in concrete is a complex blend of chemical and physical mechanism that are independent. Every admixture at optimum dosage gives better results when used with cement. The proposed research is aimed to study the compatibility of super plasticizer with different types of blended cements by investigatingflow time value. The present work is to study the behaviour of blended mixes (OPC+GGBS+ALCCOFINE) with the PCE (poly carboxylic ether) based admixtures at various dosages of both GGB,ALCCOFINE and chemical admixture. It was observed that most of the blended mixes were compatible with PCE based admixtures at dosages of around 3%. Increase in flow time has been observed with the addition of ALCCOFINE.
Key Words: GGBS, ALCCOFINE, PCE based admixture, Compatibility
An experimental study on durability and water absorption properties of pervio...eSAT Journals
Abstract Pervious concrete is a special high porosity concrete used for flatwork applications that allows water from precipitation and other source to pass through there by Reducing the Runoff from a site and Recharging Ground Water Levels. Durability and Water Absorption are important properties of Pervious Concrete. This paper represents the experimental methodology and experimental results related to durability and water absorption. Cylinders of size 100 mm Ø and 200 mm height are prepared to investigate both these properties. This investigation should be carried out at the end of 28 days for water absorption and 56 days for durability in which cylinders are immersed in Sodium Chloride (NaCl) Solution after 28 days of casting. Different concrete mix proportion such as 1:6, 1:8 and 1:10 with different size of gravel such as 18.75 mm and 9.375 mm should be used to check both these properties of pervious concrete. Test results indicates that pervious concrete made by 1:6 concrete mix proportion has more durability and less water absorption and pervious concrete made by 1:10 mix proportion has more water absorption and less durability that’s why durability and water absorption are inversely proportional to each other. Keywords: Pervious concrete, porosity, durability, water absorption, sodium chloride solution
An experimental study on durability and water absorption properties of pervio...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Design and development of non server peer 2 peer secure communication using j...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Fresh and Hardened Properties of Ground Granulated Blast Furnace Slag Made Co...IJMREMJournal
This research work was carried out on concrete specimens made with different proportion of Ground Granulated Blast Furnace Slag (GGBFS) as a cement substitution in concrete. To accomplish the goal of the research work, overall 75 cubes and 60 cylinders were made. Out of 75 cubes and 60 cylinders, 15 cubes and 12 cylinders were cast for control concrete, and 60 cubes and 48 cylinders were cast by replacing 5,10,15 and 20% of cement with GGBFS. The cubes and cylinder specimens were 100x100x100 mm and 100x200 mm respectively, and mix design was done for 28 Mpa. All specimens were tested at 3. 7, 28 and 90 days of curing ages. The fresh properties such as workability and hardened properties such as compressive and tensile strength of all mixes were determined. Tests results showed that the workability of the concrete mixes made with GGBFS was higher than control mix. As the percentage of GGBFS increased the workability also increased. Hardened properties of concrete mixes made with GGBFS was lower than control concrete at early ages of curing. At the later age, hardened properties of GGBFS made concrete was more than control concrete. Furthermore, water absorption and density of GGBFS made concrete was lower than control concrete.
Flow time analysis of blended mixes using Marsh cone apparatusAbdulRazakBH
Abstract -Admixture-Cement interaction in concrete is a complex blend of chemical and physical mechanism that are independent. Every admixture at optimum dosage gives better results when used with cement. The proposed research is aimed to study the compatibility of super plasticizer with different types of blended cements by investigatingflow time value. The present work is to study the behaviour of blended mixes (OPC+GGBS+ALCCOFINE) with the PCE (poly carboxylic ether) based admixtures at various dosages of both GGB,ALCCOFINE and chemical admixture. It was observed that most of the blended mixes were compatible with PCE based admixtures at dosages of around 3%. Increase in flow time has been observed with the addition of ALCCOFINE.
Key Words: GGBS, ALCCOFINE, PCE based admixture, Compatibility
An experimental study on durability and water absorption properties of pervio...eSAT Journals
Abstract Pervious concrete is a special high porosity concrete used for flatwork applications that allows water from precipitation and other source to pass through there by Reducing the Runoff from a site and Recharging Ground Water Levels. Durability and Water Absorption are important properties of Pervious Concrete. This paper represents the experimental methodology and experimental results related to durability and water absorption. Cylinders of size 100 mm Ø and 200 mm height are prepared to investigate both these properties. This investigation should be carried out at the end of 28 days for water absorption and 56 days for durability in which cylinders are immersed in Sodium Chloride (NaCl) Solution after 28 days of casting. Different concrete mix proportion such as 1:6, 1:8 and 1:10 with different size of gravel such as 18.75 mm and 9.375 mm should be used to check both these properties of pervious concrete. Test results indicates that pervious concrete made by 1:6 concrete mix proportion has more durability and less water absorption and pervious concrete made by 1:10 mix proportion has more water absorption and less durability that’s why durability and water absorption are inversely proportional to each other. Keywords: Pervious concrete, porosity, durability, water absorption, sodium chloride solution
An experimental study on durability and water absorption properties of pervio...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Design and development of non server peer 2 peer secure communication using j...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Comparative analysis of edge based and region based active contour using leve...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The heating pattern of the microwave dehydrator for treating petroleum crude ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Control of inverters to support bidirectional power flow in grid connected sy...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Prediction of tool wear during turning of en9 work material against coated ca...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Study of corrosion of reinforced steel bars in recycled aggregate concrete wi...eSAT Journals
Abstract Large number of old buildings and other structures have reached the end of their service life and are being demolished, resulting in generation of demolished concrete. Some of this concrete wastes are used as backfill material and much being sent to landfills. Recycling concrete by using it as replacement to new aggregate in concrete could reduce concrete waste and conserve natural source of aggregate. Recycled aggregate reduce cost savings. Use of recycled aggregate in concrete can be useful for reducing dumping problems and scarcity of virgin aggregates. In present study, in addition to the recycled aggregate, fly ash has been used to study the durability properties of recycled aggregate concrete. Properties of Recycled Aggregate Concrete were compared with Conventional Concrete with varying fly ash content. While the corrosion protection of the reinforcing steel in no substitute for design and the placement of good quality concrete, it does provide for a viable and economical extension of structural integrity and service life in the day to day and practical environment in which concrete structures are constructed. The process of corrosion, its forms of attack and consequent deterioration of reinforcement concrete structures is well understood and documented. This paper explores the economic and practical benefits offered by the application of recycled aggregate concrete and advantages of recycled aggregate concrete with and without admixtures. Keywords: Recycled aggregate, Fly ash, Concrete, and corrosion in steel
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Study on compressive strength of concrete by using treated domestic waste wat...eSAT Journals
Abstract Chapter 1deals with Introduction to treated domestic waste water utilized in concrete preparation where there is a scarcity of fresh water. Chapter 2 discusses physical properties of Materials and chemical properties of treated domestic waste water. Experimental program is presented in Chapter 4 mix proportion for M20 and M40 grade concrete are presented in this chapter. Number of specimens to be cast for different curing regimes is also presented in this chapter. Chapter 3 elaborate average compressive strength results of M20 grade concrete cast by using Tap water as mixing and curing water for Mix M1 & treated domestic waste water as mixing and curing water for Mix M2 Similarly average compressive strength results of M40 grade concrete cast by using Tap water as mixing and curing water for Mix M3 & treated domestic waste water as mixing and curing water for Mix M4. Discussion of results covers, M20 grade concrete at the age of 7days the average compressive strength for all the 2 mixes is nearly same. At the age of 14days marginal increase in compressive strength is observed in case of mix M1 but in case of mix M2 compressive strength remains same as that of 7days.And at 28days curing age decrease in compressive strength was observed .This decrease in compressive strength may be due the use of treated domestic waste water for mixing and curing. Keywords: Cement, Fine aggregate, Coarse aggregate, Treated waste water, cement concrete
Effects of coconut fibers on the properties of concreteeSAT Journals
Abstract
The materials chosen for structural up gradation should not pollute the environment and endanger bioreserves. They should be accessible to the ordinary people and be low in monetary cost. Coconut fiber is an abundant, versatile, renewable, cheap, lignocellulosic fiber and more resistant to thermal conductivity. The aim of investigation is to study the possibilities to use the coconut fiber in addition to the other constituents of concrete and to study the strength properties. A literature survey was carried out, which indicates that the detailed investigation of coconut fiber concrete is necessary. In the present study the deformation properties of concrete beams with fibers under static loading condition and the behavior of structural components in terms of compressive strength for plain concrete(PC) and coconut fiber reinforced concrete(CFRC) has been studied.
The testing of various material constituents of concrete was carried out according to the Indian Standard specifications. To identify the effects on workability and mechanical strength properties due to the addition of these coconut fibres, workability tests such slump, vee – bee, compaction factor test, Flow table tests, and the mechanical strength tests on standard specimens such as compressive strength, split tensile strength, modulus of rupture were conducted on the different aspect ratio. The standard cubes, cylinders and beams for conventional concrete and coconut fiber reinforced concrete were prepared and tested under compression testing machine and flexure testing machine respectively. The suitability of CFRC as a structural material is studied, in comparison with conventional concrete.
Keywords: CFRC1, Concrete properties2, Coir3.
A study on the performance of circular footing embedded in geogrid reinforced...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Potential utilisation of untreatedtreated textile effluent in concreteeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Self compacting concrete for slip form pavingeSAT Journals
Abstract Slip form paving has been extensively used worldwide for construction of pavements. During the process of paving, concrete mix with a slump less than 50 mm is placed in front of a paver. Because of the low consistency of the mix, a great deal of vibration is needed to move entrapped air and compact the concrete. There is a need to overcome problem by designing a concrete that would not require vibration to compact the concrete mix, at the same time stability after extrusion and high flexural strength. Mix design based on the absolute volume concept was adopted to fabricate SFSCC. Volume of paste of 0.38 and water content of 200 kg/m3 was kept constant throughout the study. Cement content was varied from 360 to 425 kg/m3, 3 mixes of SCC with GGBS (SFSCC-S), 3 mixes of SCC with 2% of alccofine replaced by cement (SFSCC-SA) and 3 mixes of SCC with 2% of metakaolin replaced by cement (SFSCC-SM) is reported. The quantity of polypropylene fibers used in all the mixes was 900 gm/m3. Slump, spread, green strength and compaction factor were evaluated for all the 9 mixes. To simulate the practical construction process, a mini paver system was fabricated. The strength parameters compressive and flexural strength of concrete was evaluated at 7 days and 28 days. Keywords: Slip form paving, alccofine, SCC, GGBS, metakaolin, SFSCC, SP.
Flexural behaviour of rc beams using foundry sand as partial replacement of f...eSAT Journals
Abstract
The main objective of the study of this work is to re-use the used foundry sand (produced at foundry industries) as a partial replacement to fine aggregate in different percentages (15 to 50%) that can be adopted in concrete along with normal river sand designed to meet the requirements of concrete of grade M50, using foundry sand with OPC have been considered in the study. Though, the main investigation is to be carried out is on the flexural behavior of reinforced foundry sand concrete beams, to facilitate proportioning of foundry sand concrete, compressive strength studies are also carried out. The tests to be carried out on around (18) singly reinforced beams of size 150 mm x 250 mm & overall length 2000 mm, simply supported over effective span 1800 mm under pure bending. The beams will be provided with adequate shear reinforcement so that the failure of the beams may due to pure flexure. The grade of concrete M50 generally with three foundry sand replacement levels (FSL) in each grade i,e, 15%, 25%, & 35% FSL are considered.
Flexural behaviour of rc beams using foundry sand as partial replacement of f...eSAT Journals
Abstract
The main objective of the study of this work is to re-use the used foundry sand (produced at foundry industries) as a partial replacement to fine aggregate in different percentages (15 to 50%) that can be adopted in concrete along with normal river sand designed to meet the requirements of concrete of grade M50, using foundry sand with OPC have been considered in the study. Though, the main investigation is to be carried out is on the flexural behavior of reinforced foundry sand concrete beams, to facilitate proportioning of foundry sand concrete, compressive strength studies are also carried out. The tests to be carried out on around (18) singly reinforced beams of size 150 mm x 250 mm & overall length 2000 mm, simply supported over effective span 1800 mm under pure bending. The beams will be provided with adequate shear reinforcement so that the failure of the beams may due to pure flexure. The grade of concrete M50 generally with three foundry sand replacement levels (FSL) in each grade i,e, 15%, 25%, & 35% FSL are considered.
Keywords: Flexural, Foundry Sand, Fine Aggregate.
Experimental studies on performance of steel fiber and polymer modified recyc...eSAT Journals
Abstract The amount of construction waste has been dramatically increased in the last decade due to increase of population & high rise building in the country. So there is an immediate need of using the aggregate from the old demolished buildings for other construction works such as roads, canals, retaining walls ...etc. Due to the lack of natural resource and dumping areas in the country, Recycling Aggregate is playing an important role in present situations. In this project a study on M25 Grade of concrete of Natural Aggregate(NA), Recycled Aggregate(RA), 30 Kg /m3 Steel Fiber Recycled Aggregate(SFRA) (aspect ratio=50), Modified Polymer Recycled Aggregate(PMRA) (Styrene butadiene rubber polymer=5%) has been carried out with water cement ratio =0.50 In this experimental investigation total number of 12 cubes ,12 beams & 12 cylinders of size 150x150mm , 150x150x700mm , 150x300mm specimens respectively were tested for 28 days & 3 cubes of Natural Aggregate, 3 cubes of Recycled Aggregate , 3 cubes of Steel Fibre Recycled Aggregate, 3 cubes of Modified Polymer Recycled Aggregate were tested in compressive testing machine for 7 days. The project is carried out at Gurunanak engineering college, Nagpur The following tests were carried out for the above specimens for 28 days
1) Compressive test 2) Split tensile test 3) Flexure test
Key words: na=natural aggregate1, ra=recycled aggregate2, sfra=steel fiber recycled aggregate3, pmra=polymer modified recycled aggregate4, conventional concrete (cc) 5,natural aggregate concrete (nac)6 with that of recycled aggregate concrete (rac7), steel fibre recycled aggregate concrete (sfrac8), polymer modified recycled aggregate concrete (pmrac)9.
EXPERIMENTAL INVESTIGATION OF RECYCLED AGGREGATE CONCRETE USING PRE-SOAKED SL...IAEME Publication
The present experimental study deals with pre-soaked slurry two stage mixing approach
(PSTSMA) for achieving best mechanical properties. The Recycled aggregate was used in three
variant as 30%, 50% and 100% replacements of Natural aggregate in M40 grade of concrete.
Through experimental study and analysis, it is observed that using PSTSMA the replacement of
30% RCA with natural coarse aggregate does not more affect the characteristics of concrete.
PSTSMA method improve up to 6.35% the strength of recycled aggregate concrete made up of
recycled aggregate at 28 days respectively w.r.t. Normal Mixing Approach(NMA). It is observed
that concrete prepared with PSTSMA gives better properties than concrete with NMA.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Behaviour of concrete beams reinforced with glass fibre reinforced polymer flatseSAT Journals
Abstract Concrete is very strong in compression but it is extremely weak in tension. To resist the tensile stress, steel reinforcement is provided in concrete. Reinforcement corrosion and structural deterioration in reinforced concrete structures are common, and prompted many researchers to seek alternative materials and rehabilitation techniques. One such material that has been offered as an alternative to mild steel reinforcement is Glass Fibre Reinforced Polymer (GFRP) bars and flats. For the repair and strengthening of structural concrete members, strengthening with Glass Fibre Reinforced Polymer (GFRP) plates is an excellent option. The present work is to study the behavior of Shear resistance of the silica coated GFRP stirrups in the shear test zone. A series of studies were conducted using silica coated GFRP stirrups in shear zone. It is observed that beams with silica coated GFRP flats shear reinforcement have shown failure at higher loads than the theoretical failure loads. Further it is observed that GFRP flats as shear reinforcement exhibit fairly good ductility. Detailed experimental investigations, results and conclusions are given in the page that follows.
Similar to Experimental study on the behaviour of retempered concrete (20)
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
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CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERS
Experimental study on the behaviour of retempered concrete
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EXPERIMENTAL STUDY ON THE BEHAVIOUR OF RETEMPERED CONCRETE K. Uma Shankar1, K. Arun Prakash2, M. Harshavardana Balaji3, S. Pradep Kumar4 1Assistant Professor, Department of Civil Engineering, Knowledge Institute of Technology, Kakkapalayam, Salem – 637 504, Tamil Nadu, India 2Assistant Professor, Department of Civil Engineering, Knowledge Institute of Technology, Kakkapalayam, Salem – 637 504, Tamil Nadu, India 3Assistant Professor, Department of Civil Engineering, Knowledge Institute of Technology, Kakkapalayam, Salem – 637 504, Tamil Nadu, India 4Assistant Professor, Department of Civil Engineering, Knowledge Institute of Technology, Kakkapalayam, Salem – 637 504, Tamil Nadu, India Abstract Ready–mixed concrete industries, are faced with a common problem known as casting delay, which usually results in a considerable loss of workability, so that concrete may be unworkable. On the other hand, improper methods of handling, lack of site organization, work scheduling and breakdown of equipment are some other causes of unexpected long delays. In such situations engineers at site, many a time reject the concrete partially set and unduly stiffened due to the time elapsed between mixing and placing. It is required to see whether such a stiffened concrete could be used on work without undue harm with use of admixtures. The process of remixing of concrete, if necessary, with addition of just the required quantity of water is known as “retempering” of concrete. The main objective of this research work is to study the behaviour and quality of retempered concrete and making it acceptable in concrete industry which would otherwise go as waste, thus saving the man hours, money and material. To achieve the above objective the workability, near surface characteristics and strength properties of retempered concrete at different time intervals such as, after 15 min, 30 min, 45 min, 60 min, 75 min, 90 min, 105 min and 120 min are found. Keywords: Retempering, workability, near surface characteristics, strength, behaviour, slump.
---------------------------------------------------------------------***-------------------------------------------------------------------- 1. INTRODUCTION
Concrete industries and, especially, ready-mixed concrete industries, are faced with a common problem known as casting delay, which usually results in a considerable loss of workability, so that concrete may be unworkable. Delay in the production and delivery of ready-mixed concrete is inevitable, which is influenced by the location of construction sites in relation to the central batching plant and traffic conditions on the route. On the other hand, improper methods of handling, lack of site organization, work scheduling and breakdown of equipment are some other causes of unexpected long delays. The practice of retempering is frequently performed to restore the initial slump and keep concrete workable at construction sites in order to cope with the need for expediting casting operations and reducing consolidation efforts. Retempering of concrete with water, superplasticizers or a combination of both, are the most common variants for resolving slump loss of concrete. However it is well-known that retempering with water alone results in a substantial strength loss, since extra water increases the water to cement ratio of the concrete mixture. In the case of ready-mixed concrete, when concrete is observed at the delivery point to have a lower-than- specified workability, there may be one or more of three possible reasons: (a) Insufficient water batched initially (b) a higher rate of evaporation (or)(absorption by aggregate) than anticipated and (c) a higher rate of hydration than expected. Based on established research, the retempering water added to offset reduction in workability, due to reasons (a) or (b), will not result in strength reduction, whereas extra water to combat (c) will result in a lower strength, due to some increase in the water to cement ratio. On the other hand, retempering with a superplasticizer would be beneficial in terms of the strength loss experienced [1].
One of the adverse effects of hot weather concreting is loss of slump. Delay in the delivery of ready mixed concrete has the same result and leads many people in the concrete industry to regain the original slump by adding water, a process known as 'retempering'. Ready-mixed (RMC) concrete, which is mixed at the plant, using a normal, well- designed concrete mix, should arrive at its destination with sufficient workability to enable it to be properly placed and fully compacted. In such circumstances, where there is a significant period of time between mixing and placing the concrete, there will be a noticeable reduction in the workability of the fresh concrete. If for any reason, the placement of the concrete is unduly delayed, then it may stiffen to an unacceptable degree and site staff would normally insist on the rejection of a batch or otherwise good concrete on the grounds of insufficient workability. If not rejected, excessive vibration would be needed to attempt to fully compact the concrete, with the risk of incomplete
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compaction, expensive repair, or, at worst, removal of the hardened concrete. If abnormal slump loss in anticipated or if transport times are significant, then the intelligent use of admixtures can alleviate the potential workability difficulties, although at additional cost, and this practice is common place. However, in cases where unforeseen delay or some other cause has lead unexpectedly to poor workability, retempering of the concrete by water, while normally considered to be bad practice, may, in reality, be contemplated as a possible course of action. The increase in the water content of the concrete immediately prior to discharge will improve the consistency, but it is widely held that there must be a subsequent increase in the water / cement (w/c) ratio which will be detrimental to the hardened concrete. Adding water to a plastic mix to increase slump is an extremely common practice, even though it is not recommended because it increases the porosity of concrete. Concrete often arrives on site more than half an hour after initial mixing. Placement operations can take anywhere from 10 to 60 minutes, depending on the field conditions and the size of the load. When the slump decreases to an unacceptable level during the operations, water is added to the mix and, very often, experienced field inspectors will tolerate what can be termed 'reasonable' retempering, i.e., enough to increase slump by 50 or 60 mm [2]. 2. MATERIALS AND METHODOLOGY In this experimental work, ordinary Portland cement (OPC) 43 grade with cement content of 413.33 Kg /m3 conforming to IS: 8112 – 1989 [3] was used. Low calcium, class F dry fly ash from the silos of Raichur thermal power station conforming to IS: 3812 (Part 1) – 2003 [4] was used. Locally available river sand with specific gravity 2.58 belonging to zone II and locally available crushed angular aggregates of maximum nominal size 20mmwith specific gravity 2.61 were used confirming toIS: 383–1970 [5] and Water fit for drinking was used. 2.1 Methodology In this experimentation, the mix design was done as per IS: 10262 – 2009 [6] and the obtained mix proportion is 1:1.58:2.71 with W/C of 0.45. The quality of retempered concrete was checked w.r.t the following four different cases
Retempered concrete without any addition
Retempered concrete with extra 5% cement + extra 5% water
Retempered concrete with fly ash (20% replacement by cement)
Retempered concrete with fly ash (20% replacement by cement) and extra 5% cement +extra 5% water
After thorough mixing of all the ingredients in dry state, the required quantity of water was added in the mix and thoroughly mixed. At this stage, the fresh concrete was kept for 15 minutes retempering time and thereafter workability tests were conducted, such as slump cone test, compaction factor test and Vee-Bee consistometer test. After conducting these tests the fresh concrete was poured into the moulds and the specimens were cast with sufficient compaction through tamping rod and vibrating table. This forms the retempered concrete for 15 minutes. Similarly the specimens were prepared with a retempering time of 30 minutes, 45 minutes, 60 minutes, 75 minutes, 90 minutes, 105 minutes and 120 minutes for all the above four combinations. All the specimens were demoulded after 24 hours of their casting and were transferred to curing tank to cure them for 28 days. After 28 days of curing the specimens were tested for the compressive strength, tensile strength, flexural strength and shear strength as per IS specifications. Near surface characteristic tests such as water absorption test and sorptivity tests were conducted to find percentage water absorption and sorptivity of retempered concrete. The sorptivity test determines the rate of capillary–rise absorption by a concrete cubes which rests on small supports in a manner such that only the lowest 30 mm of the cube is submerged. The increase in the water level of the prism with time is recorded. It has been shown that there exists a relation of the form,
S = Where S = sorptivity in mm/min0.5. i = depth of water level increased by capillary action, expressed in mm. t = time measured in minutes at which the depth determined [7]. For compressive strength test, the cubes of size 150 x 150 x 150 mm were cast and tested under compression testing machine of 2000 kN capacity as per IS: 516-1959 [8]. For splitting tensile strength test, the cylinders of 150 mm diameter and length 300 mm were cast and were tested under compression testing machine as per IS: 5816-1999 [9]. For flexural strength test, beams of dimension 100 x 100 x 500 mm were cast and were tested on an effective span of 400 mm with two point loading as per IS: 516-1959 [8]. For shear strength test L shaped specimens as shown in fig. 1 were used.
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Fig.1 Shear test on L shaped specimen The specimen was centrally placed on the compression testing machine and load is applied continuously and uniformly. The load is increased until the specimen fails and record the maximum load carried by each specimen during the test. Computation of the shear strength was done as follows.
Failure load =
Shear strength =
× 1000
Where, P = Load in kN A = Area of shear surface = 60 x 150 mm2 L1 = 25 mm L2 = 25 mm. 3.0 RESULTS AND DISCUSSIONS Table 1 gives the slump test results of different retempered concrete combinations for different retempering times, and fig. 2 shows the variation of slump. Table 2 gives the compaction factor test results of different retempered concrete combinations for different retempering times, and fig. 3 shows the variation of compaction factor. Table 3 gives the Vee–Bee test results of different retempered concrete combinations for different retempering times, and fig. 4 shows the variation of Vee–Bee time.
Table 1: Slump test results
Slump (mm) of retempered concrete
Retempering time
without any
with extra 5%
with fly ash (20%
with fly ash (20% replacement
(minutes)
cement + extra 5%
replacement by
by cement) and extra 5%
additions
water
cement)
cement + extra 5% water
0
10
15
20
25
15
10
15
20
25
30
10
15
20
25
45
8
12
15
25
60
8
12
15
20
75
5
10
12
20
90
5
8
10
15
105
4
5
8
10
120
0
3
4
5
Table 2: Compaction factor test results
Compaction factor of retempered concrete
Retempering time
without any
with extra 5%
with fly ash (20%
with fly ash (20% replacement
(minutes)
cement + extra 5%
replacement by
by cement) and extra 5%
additions
water
cement)
cement + extra 5% water
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0
0.865
0.869
0.882
0.896
15
0.862
0.868
0.876
0.893
30
0.860
0.868
0.875
0.885
45
0.858
0.866
0.873
0.880
60
0.857
0.861
0.865
0.871
75
0.851
0.859
0.861
0.865
90
0.847
0.854
0.858
0.863
105
0.845
0.851
0.855
0.858
120
0.844
0.848
0.852
0.853
Table 3: Vee–Bee test results
Vee Bee time (sec) of retempered concrete
Retempering time (minutes)
without any additions
with extra 5%
with fly ash (20%
with fly ash (20% replacement
cement + extra 5%
replacement by
by cement) and extra 5%
water
cement)
cement + extra 5% water
0
5
4
3
2
15
5
4
3
2
30
6
5
3
2
45
6
5
4
2
60
6
5
4
3
75
7
6
4
3
90
8
6
5
3
105
8
7
5
4
120
8
7
5
4
Fig. 2 Variation of slump Fig. 3 Variation of compaction factor
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Fig. 4 Variation of Vee–Bee time
It is observed that workability as measured from slump, compaction factor and Vee–Bee degree go on decreasing as the retempering time increase. This is true for retempered concrete produced without any additions, produced with extra 5% cement and water, produced with 20% replacement of cement by fly ash, and produced with 20% replacement of cement by fly ash with extra 5% cement and water. This is due to the fact that as the retempering time increases the evaporation of water takes place from the concrete mass and also concrete starts losing its plasticity, thereby reducing workability. Thus it can be concluded that the workability goes on decreasing as the retempering time increase. Also it is observed that workability as measured from slump, compaction factor and Vee–Bee degree is more for the retempered concrete produced with 20% replacement of cement by fly ash and with extra 5% cement and water as compared to other categories. Thisis true for all the retempering times.This is due to the fact that addition of fly ash and extra 5% cement and water will help in keeping the concrete in plastic state for more time thus inducing the flow characteristics.Thus it can be concluded that the workability of retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water is high as compared to other categories of retempered concrete.
Table 4 gives the water absorption test results of different retempered concrete combinations for different retempering times, and fig. 5 shows the variation of water absorption. Table 5 gives the sorptivity test results of different retempered concrete combinations for different retempering times, and fig. 6 shows the variation of sorptivity. Table 4: Water absorption test results
Water absorption (%) of retempered concrete
Retempering time (minutes)
without any
with extra 5%
with fly ash (20%
with fly ash (20% replacement
cement + extra 5%
replacement by
by cement) and extra 5%
additions
water
cement)
cement + extra 5% water
0
0.800
0.776
0.742
0.735
15
0.853
0.805
0.793
0.746
30
0.860
0.835
0.821
0.770
45
0.928
0.875
0.843
0.790
60
0.937
0.899
0.851
0.849
75
0.955
0.939
0.867
0.864
90
0.985
0.953
0.921
0.901
105
1.002
0.968
0.928
0.923
120
1.058
0.991
0.944
0.942
Table 5: Sorptivity test results
Sorptivity (mm/min0.5) of retempered concrete
without any
with extra 5%
with fly ash (20%
with fly ash (20% replacement
(minutes)
cement + extra 5%
replacement by
by cement) and extra 5%
additions
water
cement)
cement + extra 5% water
0
4.52
4.39
4.00
3.87
15
4.65
4.52
4.13
4.00
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30
4.78
4.65
4.26
4.13
45
4.78
4.65
4.26
4.13
60
4.91
4.65
4.26
4.13
75
4.91
4.78
4.39
4.26
90
5.03
4.91
4.52
4.39
105
5.29
5.03
4.78
4.52
120
5.42
5.16
4.91
4.65
Fig. 5 Variation of water absorption Fig. 6 Variation of sorptivity
It is observed that near surface characteristics as measured from water absorption and sorptivity go on increasing as the retempering time increase. This is true for retempered concrete produced without any additions, produced with extra 5% cement and water, produced with 20% replacement of cement by fly ash, and produced with 20% replacement of cement by fly ash with extra 5% cement and water. This is due to the fact that as the retempering time increases the workability decreases. This results in improper compaction of concrete which may lead to many air– voids in the concrete mass, thereby increasing water absorption and sorptivity.Thus it can be concluded that the near surface characteristics such as water absorption and sorptivity goes on increasing as the retempering time increase.
Also it is observed that near surface characteristics as measured from water absorption and sorptivity is least for retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories. This is true for all the retempering times. This is due to the fact that addition of fly ash with extra 5% cement and water induce plasticity to concrete resulting in more workability. This concrete can be easily compacted thereby reducing the air voids. Thus it can be concluded that the near surface characteristics such as water absorption and sorptivity is least for retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories of retempered concrete.
Table 6 gives the results of compressive strength of retempered concrete for different combinations with different retempering times, and fig. 7 shows the variation of compressive strength. Table 7 gives the results of tensile strength of retempered concrete for different combinations with different retempering times, and fig. 8 shows the variation of tensile strength. Table 8 gives the results of flexural strength of retempered concrete for different combinations with different retempering times, and fig. 9 shows the variation of flexural strength. Table 9 gives the results of shear strength of retempered concrete for different combinations with different retempering times, and fig. 10 shows the variation of shear strength.
Table 6: Results of compressive strength
Compressive strength (MPa) of retempered concrete
Retempering time
with extra 5%
with fly ash
with fly ash (20%
without any
replacement by cement) and
(minutes)
cement + extra 5%
(20% replacement
additions
extra 5% cement + extra 5%
water
by cement)
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water
0
42.22
42.37
42.67
43.11
15
42.81
43.26
43.41
43.56
30
43.11
43.70
43.85
44.15
45
43.41
44.15
44.44
44.89
60
42.37
42.96
43.11
43.41
75
41.48
42.07
42.37
42.67
90
40.74
41.33
41.63
41.78
105
40.00
40.15
40.44
40.74
120
39.11
39.26
39.56
40.30
Table 7: Results of tensile strength
Tensile strength (MPa) of retempered concrete
Retempering time
with extra 5%
with fly ash
with fly ash (20%
without any
replacement by cement)
(minutes)
cement + extra
(20% replacement
additions
and extra 5% cement +
5% water
by cement)
extra 5% water
0
3.68
3.77
3.82
3.91
15
3.77
3.87
3.96
4.10
30
3.87
3.96
4.10
4.20
45
3.96
4.15
4.29
4.39
60
3.87
4.01
4.10
4.20
75
3.68
3.87
3.91
3.96
90
3.58
3.68
3.72
3.82
105
3.44
3.49
3.54
3.63
120
3.30
3.39
3.44
3.54
Table 8: Results of flexural strength
Flexural strength (MPa) of retempered concrete
Retempering time
with extra 5%
with fly ash
with fly ash (20%
without any
replacement by cement)
(minutes)
cement + extra
(20% replacement
additions
and extra 5% cement +
5% water
by cement)
extra 5% water
0
6.47
6.80
7.13
7.40
15
6.93
7.20
7.40
7.67
30
7.20
7.47
7.93
8.07
45
7.73
7.87
8.27
8.73
60
6.80
7.20
7.47
7.87
75
6.47
6.80
7.20
7.60
90
6.07
6.47
6.80
7.33
105
5.67
6.13
6.53
6.80
120
5.47
5.80
6.33
6.60
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Table 9: Results of shear strength
Shear strength (MPa) of retempered concrete
Retempering time
with extra 5%
with fly ash
with fly ash (20%
without any
replacement by cement)
(minutes)
cement + extra
(20% replacement
additions
and extra 5% cement +
5% water
by cement)
extra 5% water
0
3.70
4.07
4.26
4.44
15
4.07
4.26
4.44
4.63
30
4.26
4.63
4.81
5.00
45
4.63
4.81
5.19
5.37
60
4.44
4.63
4.81
5.00
75
3.89
4.07
4.44
4.81
90
3.52
3.70
4.07
4.44
105
3.15
3.33
3.70
4.07
120
2.96
3.15
3.33
3.70
Fig. 7 Variation of compressive strength Fig. 9 Variation of flexural strength
Fig. 8 Variation of tensile strength Fig. 10 Variation of shear strength
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Volume: 03 Special Issue: 11 | NCAMESHE - 2014 | Jun-2014, Available @ http://www.ijret.org 264
It is observed that compressive strength, tensile strength, flexural strength and shear strength of retempered concrete goes on increasing up to 45 minutes of retempering time. Thereafter all the strengths start decreasing. This is true for retempered concrete produced without any additions, produced with extra 5% cement and water, produced with 20% replacement of cement by fly ash, and produced with 20% replacement of cement by fly ash with extra 5% cement and water. This is due to the fact that above 45 minutes of retempering time the concrete looses the plasticity seriously and remixing the concrete beyond 45 minutes will not reunite the concrete particles to adhere together. Thus it can be concluded that compressive strength, tensile strength, flexural strength and shear strength of retempered concrete goes on increasing up to 45 minutes of retempering time. Therefore retempering can be allowed up to 45 minutes. Also it is observed that compressive strength, tensile strength, flexural strength and shear strength of concrete is more for retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories. This is true for all the retempering times. This is due to the fact that addition of fly ash and extra 5% cement and water will help in keeping the concrete in plastic state which helps in thorough compaction of concrete resulting in higher strength.Thus it can be concluded that compressive strength, tensile strength, flexural strength and shear strength of concrete is more for retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories. 4. CONCLUSIONS Following conclusions can be drawn based on the experimentations conducted on the retempered concrete.
Workability goes on decreasing as the retempering time increase.
Workability of retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water is high as compared to other categories of retempered concrete.
Near surface characteristics such as water absorption and sorptivity goes on increasing as the retempering time increase.
Near surface characteristics such as water absorption and sorptivity is least for retemperedconcrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories of retempered concrete.
Compressive strength, tensile strength, flexural strength and shear strength of retemperedconcrete goes on increasing up to 45 minutes of retempering time. Therefore retempering can be allowed up to the time of 45 minutes.
Compressive strength, tensile strength, flexural strength and shear strength of concrete is more for retempered concrete produced with 20% replacement of cement by fly ash with extra 5% cement and water as compared to other categories.
REFERENCES
[1]. IS: 8112 – 1989, ―43 Grade ordinary Portland cement—Specifications‖ (First revision),BIS, New Delhi, May 1990.
[2]. IS: 3812 (Part 1) – 2003, ―Pulverized fuel ash – Specification‖ (Second revision),BIS, New Delhi, October 2003.
[3]. IS: 383 – 1970, ―Specifications for coarse and fine aggregate from natural sources for concrete‖ (Second revision), BIS, New Delhi, April 1971.
[4]. IS: 10262 – 2009, ―Concrete mix proportioning – Guidelines‖ (First revision), BIS, New Delhi, July 2009.
[5]. IS: 10262-1982 Recommended Guidelines for Concrete Mix Design.
[6]. SANTHAKUMAR.A.R,―Concrete Technology‖, Oxford Publishing & Co., New Delhi, 2007, First Edition.
BIOGRAPHIES
Prof.K.UmaShankar presently working as Assistant Professor in the department of Civil Engineering at Knowledge Institute of Technology. He has more than 4 years of teaching experience. He has published 5 papers in the reputed International and National journals & Conferences.
Mr.K.ArunPrakash is presently working as Assistant Professor in the Department of Civil Engineering at Knowledge Institute of Technology. He has more than 3 years of teaching experience. He has published 1 paper in the International Conference and 2 papers in the National Conferences.
Mr.M.Harshavardana Balaji is presently working as Assistant Professor in the Department of Civil Engineering at Knowledge Institute of Technology. He has more than 2 years of teaching experience. He has published 1 paper in the International Conference and 2 papers in the National Conferences.
S.PradeepKumar is presently working as Assistant Professor in the Department of Civil Engineering at Knowledge Institute of Technology. He has more than 2 years of teaching experience. He has published 1 paper in the International Conference and 2 papers in the National Conferences.