scholarly journals USE OF RECYCLED POLYPROPYLENE GRAINS AS PARTIAL REPLACEMENT OF FINE AGGREGATE IN REINFORCED CONCRETE BEAMS

2015 ◽  
Vol 6 (4) ◽  
pp. 184-190 ◽  
Author(s):  
Joseph Olawale Akinyele ◽  
Ramhadhan Wanjala Salim ◽  
Gbolahan Oyeti
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Waste Product ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Partial Replacement ◽  
Sieve Analysis ◽  
Fine Aggregate ◽  
Recycled Polypropylene

Waste product from polyethylene materials are non-biodegradable and they form the bulk of the materials been used today. This paper looked into how this waste product was recycled in to polypropylene grains of sizes <4.5 mm and used to partially replace fine aggregate in concrete. Sieve analysis was carried out on the recycled polypropylene waste. Reinforced concrete beams (600 mm x 150 mm x 200 mm) and concrete cubes (150 mm x 150 mm x 150 mm) were made from the mixture of the recycled material at different percentages of 0%, 4%, 8%, 12% and 16%. The beams were subjected to bending moment test, while the cubes were subjected to compressive strength test. Results revealed that 43.71% of polypropylene grains passed through the 4.75 mm sieve. The compressive strength of the 4% mixture was 16.28 N/mm2 while the control was 19.07 N/mm2. The bending moment test showed that the control mix has the highest value of 14.70 kNm, while the 12% and 16% has the lowest value of 8.40 kNm each. Deflections in the polypropylene mixes were generally higher than the control. The work concluded that recycled polypropylene grains can be used as partially replacement of fine aggregate in concrete at below 4% replacement.

scholarly journals Flexural behaviour of steel fibre reinforced concrete beams made with copper slag as partial fine aggregate replacement

2020 ◽  
Vol 184 ◽  
pp. 01077
Author(s):  
DAS Mohd Areef ◽  
P Srinivasa Rao ◽  
V Srinivasa Reddy ◽  
D Mohd Azeem Zubair
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Free Water ◽  
Copper Slag ◽  
Reinforced Concrete Beams ◽  
Experimental Investigations ◽  
Fine Aggregate ◽  
River Sand ◽  
Slag Content

Lately, development of concrete using industrial byproducts has garnered major significance in the construction industry in order to overcome problems associated with depleted natural resources. As, river sand is costly and also large scale exhaustion of these sources generates environmental harms, a substitute or replacement product for concrete industry is very indispensable. In such a situation, the copper slag can be proposed as an alternative to the river sand, which is an industrial by-product obtained from the manufacturing of copper. The present investigation assesses the incorporation of copper slag in concrete (CSC). In this paper, experimental investigations are carried to understand the flexural characteristics such as such as first crack, ultimate load carrying capacity, maximum crack width and deflection at service load and at centre of steel fibred copper slag mixed under-reinforced concrete beams. Results showed that the compressive strength of concrete decreases as copper slag content increases beyond 40%. The reduction in compressive strength beyond 40% replacement of river sand due to the increase in free water content in concrete mixes due to the low absorption properties of copper slag which can cause excessive bleeding at higher copper slag content. The load-deflection behaviour of under-reinforced, normal and copper slag concrete beams is witnessed to be alike apart from the increased values of ultimate failure loads and ultimate deflections at failure in steel fibred copper slag concrete beams.

Analysis on Deformation of Pre-Splitting Steel Reinforced Concrete Beams Strengthened by Prestressed CFRP

2011 ◽  
Vol 243-249 ◽  
pp. 929-933
Author(s):  
Na Ha ◽  
Lian Guang Wang ◽  
Shen Yuan Fu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Steel Reinforced Concrete ◽  
Cfrp Sheets ◽  
Deformation Curves ◽  
Prestressed Cfrp Sheets ◽  
Theoretical Results

In order to improve the bearing capacity of SRC which is related with deformation and stiffiness, SRC beams should be strengthened by CFRP. Based on the experiment of six pre-splitting steel reinforced concrete beams strengthened with (Prestressed) CFRP sheets, the deformation of beams are discussed. Load-deformation curves are obtained by the experiment. Considering the influence of intial bending moment on SRC beams, the calculated deformation formulas of SRC beams strengthened by (Prestressed) CFRP are deduced. The results showed that the load-deformation curves of normal and strengthened beams respectively showed three and two linear characteristics. The theoretical results which calculated by the formulas of deformation are well agreement with the experimental results.

scholarly journals Experimental Investigation of Shear Strength for Steel Fibre Reinforced Concrete Beams

2021 ◽  
Vol 15 (1) ◽  
pp. 81-92
Author(s):  
Constantinos B. Demakos ◽  
Constantinos C. Repapis ◽  
Dimitros P. Drivas
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Steel Fibre ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete

Aims: The aim of this paper is to investigate the influence of the volume fraction of fibres, the depth of the beam and the shear span-to-depth ratio on the shear strength of steel fibre reinforced concrete beams. Background: Concrete is a material widely used in structures, as it has high compressive strength and stiffness with low cost manufacturing. However, it presents low tensile strength and ductility. Therefore, through years various materials have been embedded inside it to improve its properties, one of which is steel fibres. Steel fibre reinforced concrete presents improved flexural, tensile, shear and torsional strength and post-cracking ductility. Objective: A better understanding of the shear performance of SFRC could lead to improved behaviour and higher safety of structures subject to high shear forces. Therefore, the influence of steel fibres on shear strength of reinforced concrete beams without transverse reinforcement is experimentally investigated. Methods: Eighteen concrete beams were constructed for this purpose and tested under monotonic four-point bending, six of which were made of plain concrete and twelve of SFRC. Two different aspect ratios of beams, steel fibres volume fractions and shear span-to-depth ratios were selected. Results: During the experimental tests, the ultimate loading, deformation at the mid-span, propagation of cracks and failure mode were detected. From the tests, it was shown that SFRC beams with high volume fractions of fibres exhibited an increased shear capacity. Conclusion: The addition of steel fibres resulted in a slight increase of the compressive strength and a significant increase in the tensile strength of concrete and shear resistance capacity of the beam. Moreover, these beams exhibit a more ductile behaviour. Empirical relations predicting the shear strength capacity of fibre reinforced concrete beams were revised and applied successfully to verify the experimental results obtained in this study.

Guidelines for flexural design of FRP reinforced concrete beams

2020 ◽  
pp. 002199832097373
Author(s):  
Fares Jnaid
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Large Diameter ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Concrete Compressive Strength ◽  
Load Carrying ◽  
Multiple Variables

This paper investigates the effects of different parameters on the live load carrying capacity of concrete beams reinforced with FRP bars. The author performed a parametric study utilizing an innovative numerical approach to inspect the effects of multiple variables such as reinforcement ratio, concrete compressive strength, span to depth ratio, FRP type, and bar diameter on load carrying capacity of FRP reinforced concrete beams. This study concluded that unless the span to height ratio is smaller than 8, tension-controlled sections are impractical as they do not meet code requirements for serviceability. In addition, it is recommended to use higher reinforcement ratios when using larger span to depth ratios and/or when using CFRP reinforcing bars. Moreover, larger number of bars with small diameter is more practical than fewer large diameter bars. Furthermore, this research suggests that increasing the concrete compressive strength is associated with a significant increase in the ultimate flexural capacity of FRP reinforced beams.

Composite design method for masonry walls on concrete beams

1983 ◽  
Vol 10 (3) ◽  
pp. 337-349 ◽  
Author(s):  
B. Stafford Smith ◽  
L. Pradolin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Method ◽  
Design Procedure ◽  
Bending Moment ◽  
Reinforced Concrete Beam ◽  
Masonry Wall ◽  
Reinforced Concrete Beams ◽  
Steel Beams ◽  
Arch Action

This paper describes a design method for structures consisting of a vertically loaded masonry wall supported by a reinforced concrete beam, taking account of the composite tied-arch action of the wall and beam. Experimental results have shown that the behaviour of walls on reinforced concrete beams is similar enough to that of walls on steel beams to allow the development of a design procedure for the former using similar principles to that for walls on steel beams. Therefore, the design approach is based on the assumption of triangular distributions of vertical stress at the wall–beam interface, where the length of the distributions are a function of the beam-to-wall relative stiffness. In the design method the beam flexural stiffness is designed to give an adequate distribution of the interface stress so that the maximum stress in the wall does not exceed allowable limits. The beam is also designed with flexural and shear reinforcement sufficient to resist the bending moment, tie force, and shear forces applied by the normal and shear interface loading. Experimental evidence as well as analytical results are cited to support the assumptions and the resulting design method.

scholarly journals Flexural Behaviour of RCC Beams Partially Replacing Cement by Dolomite Powder and Sand by Quarry Dust

2019 ◽  
Vol 8 (12) ◽  
pp. 5280-5290
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Concrete Beams ◽  
Low Cost ◽  
Waste Material ◽  
Reinforced Concrete Beams ◽  
Split Tensile Strength ◽  
Quarry Dust

The present Investigation is aimed at utilizing low cost material Dolomite powder and waste material Quarry dust as partial replacement of cement and sand in concrete. This experimental investigation is carried out in three stages. In 1st stage M25 grade of concrete is produced by replacing cement by 0%, 6%, 12% and 18% of Dolomite Powder. In 2nd Stage concrete is produced by keeping the optimum 12% of dolomite powder as constant and sand is replaced by quarry dust in the percentage of 0%, 25%, 35% and 45%. In 3rd stage the optimum percentage of Dolomite Powder and Quarry Dust (DP+QD) Concrete are used to determine the compressive strength, split tensile strength and flexural strength of concrete and to check the flexural behavior of RCC beams. It is found that the concrete made of low cost material dolomite powder and waste material quarry dust increases the compressive strength, split tensile strength and flexural strength of concrete when compared to that of normal concrete. It also concluded that the first crack load and ultimate load of dolomite powder and quarry dust reinforced concrete beams increases when compared with normal reinforced concrete beams. From study it is concluded that the low cost material Dolomite powder & Quarry dust can be used in construction works which results in construction cost. By using natural resources the environment is protected.

scholarly journals Influence of the percentage of reinforcement by unstressed rebar on the deformability of pre-stressed RC beams

2021 ◽  
Vol 27 (3) ◽  
pp. 212-216
Author(s):  
Yaroslav Blikharskyy ◽  
Jacek Selejdak ◽  
Taras Bobalo ◽  
Roman Khmil ◽  
Mykhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Practical Significance ◽  
Pure Bending ◽  
Static Loads ◽  
Steel Bars ◽  
Periodic Profile

Abstract This article presents the materials of deformability studies of pre-stressed steel-concrete beams reinforced with a package of reinforcement with different ratio of tape and rebar in the pure bending moment zone. The aim of the research was determination of the reinforcement percentage influence, for pre-stressed reinforced concrete beams reinforced with a package of reinforcement on their deformability. Also, the aim was to evaluate the effectiveness of using pre-stressed rebar in combined reinforcement. The practical significance of the experimental research is to study the deformability in pre-stressed bending elements with external tape and rebar reinforcement, taking into account the influence of different ratios of reinforcement areas within the combined reinforcement and development of proposals for such structures` calculation and design. The scientific novelty of the research is in obtaining the deformability characteristics of reinforced concrete beams reinforced with a package of reinforcement (tape and steel bars with periodic profile) with different ratios in the case of static loads` action.

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