scholarly journals Flexural Behavior of Rubberized Reinforced Concrete Beams

2018 ◽  
Vol 7 (4.20) ◽  
pp. 316 ◽  
Author(s):  
Adel A. Al-Azzawi ◽  
Dalia Shakir ◽  
Noora Saad
Keyword(s):  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fiber Content ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Rubberized Concrete ◽  
Normal Concrete ◽  
Rubber Material ◽  
Rubber Waste

In Iraq, the use of rubber waste material in concrete is an interesting topic due to its availability in large volumes. Researches of applications of rubber waste in concrete have been increased since 2003. Many studies carried out to investigate the performance of concrete using different ratios of rubber as a replacement to fine or coarse aggregate. In this research, rubber wastes from scrapped tires have been added as fiber to concrete mix with presence of 0.5% superplasticizer. The flexural behavior of concrete beams, mechanical properties of concrete and workability of concrete mixes have been studied. Rubber fibers ranging from (2-4) mm were added in percentages of 0.5% and 1%) of the cement weight. The results have demonstrated that the addition of rubber material as fibers in natural aggregate concrete enhances its ductility, compressive strength and tensile strength compared to the normal concrete. The effect of rubber fiber content is found to be significant on the behavior of tested beams. If the fiber content increased from 0 to 0.5% the cracking load increased by 60 % and ultimate load increased by 21%. For rubberized concrete, if the fiber content increased from 0.5 to 1.0%, the cracking load decreased 7% and ultimate load increased by 4%.   

FLEXURAL BEHAVIOR OF STRENGTHENED AND RPIARED SUSTAINABLE R.C. BEAMS USING REACTIVE POWDER CONCRETE JACKET

2021 ◽  
Vol 25 (Special) ◽  
pp. 4-44-4-56
Author(s):  
Mohammed S. Zimmawe ◽  
◽  
Nagham T. Hamad ◽  
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Reactive Powder Concrete ◽  
Limit Condition ◽  
Reactive Powder

Thin fiber reinforcement and rehabilitation of reinforced concrete beams Concrete jackets have several benefits, including increased ultimate load and improved serviceability limit condition. The current paper was carried out to investigate the effect of the strengthening and repairing by using reactive powder concrete(RPC) jacket for reinforced concrete beams that’s casted with recycled coarse aggregate (RCA) in enhancement the mechanical properties such as load capacity and deflection . Nine reinforced concrete beams mm were casted by using RCA with constant details and jacketed with RPC with variable of steel fiber content and jacket thickness to estimate the optimum details. The result showed the effectiveness of the proposed technique in both deflection and ultimate load.

Flexural performance of reinforced concrete beams made by innovative post-filling coarse aggregate process

2021 ◽  
pp. 136943322110093
Author(s):  
Jinqing Jia ◽  
Qi Cao ◽  
Lihua Zhang ◽  
Jiayu Zhou
Keyword(s):  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Filling Ratio ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Aggregate Concrete ◽  
Flexural Performance ◽  
Peak Value

Concrete made by post-filling coarse aggregate process could reduce the cement content greatly compared with traditional concrete placement method. Thus, it not only lowers the production cost of concrete through lower usage of cement but also reduces the CO2 emissions to the environment. In this paper, the compressive and tensile strength of post-filling coarse aggregate concrete with different post-filling ratios (PFRs) (0%, 10%, 15%, 20%, 25%, 30%) and concrete strength grades (C30, C40, C50) were first studied. Then the flexural performance of nineteen concrete beams with different concrete strength, post-filling ratios, reinforcement ratios was investigated. The experimental results showed that the compressive strength and elastic modulus of the post-filling coarse aggregate concrete increased with the increase of the post-filling ratio of coarse aggregate, reaching the peak value at the filling ratio of 20%. It indicated that there was no obvious difference in the failure mode as well as middle-span deflections between post-filling coarse aggregate concrete (PFCC) beams and ordinary concrete (OC) beams. Ductile failure was observed for all nineteen specimens. Results demonstrated that the cracking load, yield load, and ultimate load of the post-filling coarse aggregate concrete beams all reached the peak value at the post-filling ratio of 20%. In addition, the theoretical predictions of cracking loads and ultimate load carrying capacities matched the experimental results in satisfactory agreement.

scholarly journals Flexural Behavior of Fiber Reinforced Self-Compacting Rubberized Concrete Beams

2020 ◽  
Vol 26 (2) ◽  
pp. 111-128
Author(s):  
Tamara M. Hasan ◽  
Ahmed S. Ali
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Monotonic Loading ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Repeated Loading ◽  
Fiber Reinforced ◽  
Waste Tire

The massive growth of the automotive industry and the development of vehicles use lead to produce a huge amount of waste tire rubber. Rubber tires are non-biodegradable, resulting in environmental problems such as fire risks. In this search, the flexural behavior of steel fiber reinforced self-compacting concrete (SFRSCC) beams containing different percentages and sizes of waste tire rubbers were studied and compared them with the flexural behavior of SCC and SFRSCC. Micro steel fiber (straight type) with aspect ratio 65 was used in mixes. The replacement of coarse and fine aggregate was 20% and 10% with chip and crumb rubber. Also, the replacement of limestone dust and silica fume was 50%, 25%, and 12% with ground rubber and very fine rubber, respectively. Twelve beams with small-scale (L=1100mm, h = 150mm, b =100mm) were tested under two points loading (monotonic loading). Fresh properties, hardened properties, load-deflection relation, first crack load, ultimate load, and crack width were investigated. Two tested reinforced concrete beams from experimental work were selected as a case study to compare with the results from ABAQUS program (monotonic loading). These two reinforced concrete beams were simulated as a parametric study under repeated loading using this finite element program. The results showed that the flexural behavior of SFRSCC beams containing rubber was acceptable when compared with flexural behavior of SCC and SFRSCC beams (depended on load carrying capacity). Cracks width was decreased with the addition of steel fibers and waste tires rubber.  An acceptable agreement can be shown between the results of numerical analysis and the results obtained from experimental test (monotonic loading). Insignificant ultimate load differences between the results of monotonic loading and repeated loading                                                                                                                                                                                           

Experimental Research on Ceramsite Concrete Beams

2012 ◽  
Vol 166-169 ◽  
pp. 708-711
Author(s):  
Chuang Du ◽  
Wen Ling Tian ◽  
Xiao Wei Wang ◽  
De Jun Wang
Keyword(s):  
Concrete Beam ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Polypropylene Fiber ◽  
Flexural Behavior ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Normal Concrete ◽  
Ordinary Concrete ◽  
Cover Thickness

Six specimens, including 4 ceramsite concrete beams(one of beams mixed into the polypropylene fiber ) and 2 normal concrete beams, were tested to investigate the flexural behavior. The test results show that cracking load of ceramsite concrete beams is slightly smaller than the ordinary concrete beam and cracking load of ceramsite concrete beams has significantly improved after mixing into the polypropylene fibers. The ultimate load of ceramsite concrete beams are no less than ordinary concrete beam,and fibers have not effects on the increase of ultimate load. Load-deflection curves were compared,and the results show that stiffness of ceramsite concrete beam is less than ordinary concrete beam. Ductility of ceramsite concrete beam is poorer than ordinary concrete beam. Fibers improve the stiffness of ceramsite concrete beam. Cover thickness of concrete beam has little effect on the performance of ceramsite concrete beam.

scholarly journals FLEXURAL BEHAVIOR OF REINFORCED LIGHTWEIGHT CONCRETE BEAMS MADE WITH ATTAPULGITE AND ALUMINUM WASTE

2021 ◽  
Vol 25 (02) ◽  
pp. 24-35
Author(s):  
Zahraa A. Mirza ◽  
◽  
Nibras N. Khalid ◽  
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Ultimate Load ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Lightweight Aggregate ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Lightweight Aggregate Concrete ◽  
Flexural Ductility

Lightweight concrete reduces the total dead load of structural elements and seismic loads significantly. This paper presents the production Attapulgite Lightweight aggregate concrete (ALWAC) and its effect on the flexural behavior of reinforced concrete beams. Attapulgite was treated with sodium hypochlorite of 6% concentration for 24 hours. The variable considered was the aluminum waste (AW), used as a fiber, of fraction (0, 0.5 and 1%) by concrete volume. Behavior was investigated in terms of cracking and ultimate load, load-deflection relationship, failure mode, crack patterns and flexural ductility. The mechanical properties of the ALWAC were studied. It was observed that, Attapulgite improves the mechanical properties of concrete when comparing the experimental value with theoretical ones for the reference mixture. AW has a disparate effect on the mechanical properties of ALWAC. The increase in the proportions of AW showed an increase in the cracking load and decrease in the ultimate load by 37.14% and 22.45 %, respectively, at AW of 1%. Experimental value of ultimate load in all beams was higher than the theoretical value (ACI simplified method). AW increases the deflection at the same magnitude of applied load, and reduces the number and propagation of the flexural cracks in beams. All beams exhibited a typical tension failure mode and failed in ductile manner.

scholarly journals Ductility Improvement of R.C Beams with Large Web opening by using Reactive Powder Concrete Layers

2018 ◽  
Vol 25 (3) ◽  
pp. 30-39
Author(s):  
Husain Khalaf Jarallah ◽  
Nidaa Qassim Jassim
Keyword(s):  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Reactive Powder Concrete ◽  
Normal Concrete ◽  
Simply Supported ◽  
Hybrid Beam ◽  
Web Opening ◽  
Hybrid Beams ◽  
Reactive Powder

In this investigation the effect of large web opening on the on the behaver of beams made by normal concrete (NC) and reactive powder concrete (RPC) have been studied. The experimental work consists of casting and testing in flexure 12 rectangular simply supported reinforced concrete beams. The main parameters of this test are opening locations and normal concrete and RPC location with is the section. The ultimate loads, cracking loads, load -deflection behavior, skew of the openings (deflection at the two opposite corners of openings) and ductility were discussed. These results showed that increase ultimate loads (Pu) and stiffness by increase RPC layers. The using RPC layers increase ultimate load about (1-30) %. Using RPC in compression fiber is found to be more effective than using RPC in tension fiber. The cracking load of hybrid beam with one layer of RPC in compression fiber (having one opening) higher than NC beams by 48.5%. The ultimate strength was decreases with increases opening about (4-21)%, thus indicating that the stiffness decreases accordingly. Hybrid beams with RPC in tension fiber failed with less crack than those for hybrid beams with RPC in compression fiber at the same number of openings. The skew at opening of flexural zone show greater values than the skew at opening in shear zone for each beam until failure. The increase in the number of openings leads to increase in the ductility because it reduces the strength of beams.

scholarly journals Flexural Behavior of Reinforced High-Performance Concrete Beams Made with Steel Slag Coarse Aggregate

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Saaid I. Zaki ◽  
Ibrahim M. Metwally ◽  
Sameh A. El-Betar
Keyword(s):  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Steel Slag ◽  
Physical And Mechanical Properties ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
New Material ◽  
Waste Particles

In recent years, an emerging technology termed high-performance concrete (HPC) has become popular in construction industry. The constituent materials of HPC depend on the desired characteristics and the availability of suitable local economic alternatives. One of these alternatives is steel slag waste material. It is an industrial by-product waste particles resulted from reinforcing steel bars manufacture, its production is very huge; total quantity produced from all steel rebars manufacture factories in Egypt is nearly million tons/year. HPC made with steel slag aggregate (SSA) is considered as green concrete, using of steel-slag as a coarse aggregate increases the probability of consuming such large accumulations of slag (in HPC industry) which they represent as a waste and polluted material in environment. A total of eight under, balanced and over reinforced concrete beams were fabricated and tested. RC beams were made with HPC having compressive strength of 58.1 and 75.6 MPa and tensile reinforcement ratio in the range of 0.90 to 4.3%. Data presented concentrated on the chemical, physical, and mechanical properties of the used new material (SSA) and the flexural behavior of reinforced high-performance concrete beams made with steel slag coarse aggregate (RHPC-SSA) beams. It was observed that the RHPC-SSA beams can give satisfactory structural performance according to the American and Egyptian Building Codes.

scholarly journals ANALISIS RETAK LENTUR PADA BALOK BETON BERTULANG MUTU TINGGI YANG DIPERBAIKI DENGAN INJEKSI EPOXY

2018 ◽  
Vol 1 (4) ◽  
pp. 831-844
Author(s):  
Fiany Fajar Puspita ◽  
Teuku Budi Aulia ◽  
Mochammad Afifuddin
Keyword(s):  
Reinforced Concrete ◽  
High Strength Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Construction Material ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Strength Concrete ◽  
Flexural Failure

Abstract: High Strength Concrete is an alternative construction material for supporting heavy loads. High strength concrete is a brittle material that susceptible to crack. One of the concrete repairing method is epoxy injection. The aim of this study is to determine the flexural behavior of high strength reinforced concrete beams after cracking and repaired with the Epoxy Injection. This study used 4 (four) high strength reinforced concrete beams (BBMT) with (15 ´ 30 ´ 220) cm dimention. One of the beam is for comparison (BBMT Normal) and 3 (three) other beams were tested at the age 7 days (BBMT E-7), 14 days (BBMT E-14) and 28 days (BBMT E-28) after repaired. The beams is designed to have flexural failure by using a compression reinforcement and shear reinforcement of 11.9 mm and 15.8 mm for tensile reinforcement. The water cement ratio for mix design is 0,25 obtained at 28 days is 66,62 MPa. The results shows that all the beams have flexural failure in agreement to the early design. The ultimate load of BBMT Normal is 17,65 ton with deflection equal to 10,36 mm. Based on theoretical calculation the load is 16.04 tons and deflection 14.38 mm. BBMT E-7 after epoxy injection ultimate load is 20,89 tons and deflection is 41.99 mm. BBMT E-14 ultimate load 21,79 tons and deflection equal to 44,27 mm. The ultimate load of BBMT E-28 is 25.52 tons and deflection 13.49 tons. The increase of load are 18.36%, 23.46% and 44.59% when compared with BBMT Normal. Based on the observation on the BBMT after epoxy injection, no cracks evident in most of the injected areas, new cracks appearing around the area of initial crack. It is concluded that epoxy injection is capable to increase the capacity of repaired high strength concrete and th flexural strength of the epoxy repaired concrete beams is increase as the age increased. Abstrak: Beton mutu tinggi merupakan salah satu alternatif material konstruksi untuk pembebanan besar. Beton mutu tinggi memiliki sifat yang kaku sehingga rentan terhadap retak. Salah satu metode perbaikan pada retak beton yaitu injeksi epoxy. Penelitian ini dilakukan dengan tujuan untuk mengamati perilaku lentur pada balok beton bertulang mutu tinggi yang diperbaiki dengan injeksi epoxy. Penelitian ini menggunakan 4 (empat) buah benda uji yaitu balok Beton Bertulang Mutu Tinggi (BBMT) dengan ukuran (15 ´ 30 ´ 220) cm. Benda uji pertama sebagai pembanding (BBMT Normal) dan 3 (tiga) benda uji lain diuji sesuai dengan umur perbaikan betonnya yaitu BBMT E-7 (7 hari), BBMT E-14 (14 hari) dan BBMT E-28 (28 hari). Balok didesain mengalami gagal lentur dengan menggunakan tulangan tekan dan tulangan geser berdiameter 11,9 mm ulir serta tulangan tarik 15,8 mm ulir. Kuat tekan beton mutu tinggi yang didapat dari benda uji kontrol kubus sebesar 66,62 MPa dengan FAS 0,25. Hasil penelitian menunjukkan bahwa semua benda uji balok mengalami gagal lentur sesuai dengan desain awal. Beban maksimum yang mampu dicapai oleh balok BBMT Normal adalah 17,65 ton dengan lendutan sebesar 10,36 mm. Perhitungan teoritis beban BBMT Normal yaitu 16,04 ton dan lendutan 14,38 mm. BBMT E-7 setelah diinjeksi menghasilkan beban sebesar 20,89 ton dan lendutan 41,99 mm. Pada BBMT E-14 beban yang dicapai 21,79 ton dan lendutan sebesar 44,27 mm. Beban maksimum pada BBMT E-28 yaitu 25,52 ton dan lendutan 13,49 ton. Masing-masing persentase peningkatan beban jika dibandingkan dengan BBMT Normal adalah 18,36%, 23,46% dan 44,59%. Pola retak yang terjadi pada balok BBMT setelah diinjeksi menunjukkan bahwa tidak terjadi retak pada sebagian besar daerah yang diinjeksi, retak baru muncul di sekitar retak awal. Dapat disimpulkan bahwa injeksi epoxy mampu meningkatkan kapasitas beton mutu tinggi dan umur perbaikan beton mempengaruhi nilai beban maksimum yang mampu dicapai oleh beton.

scholarly journals Flexural Behavior of Damaged Lightweight Reinforced Concrete Beams Strengthened by CFRP

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Ali I. Salahaldin ◽  
◽  
Muyasser M. Jomaa’h ◽  
Dlovan M. Naser ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Load Carrying Capacity ◽  
Normal Concrete ◽  
Load Carrying

One of the most common methods of strengthening, rehabilitation, or repairing of structural lightweight concrete (LWC) elements is the external carbon fiber reinforced polymer (CFRP) strips. This paper presents an experimental study on the flexural behavior of reinforced concrete beams which comprise lightweight aggregate concrete, in different proportions, strengthened by CFRP sheets. The experimental program included six specimens with a 1500mm effective span. Two of the specimens were normal concrete beams. Another two samples were lightweight beams with a 50% aggregate replacement with pumice. The last two specimens were lightweight concrete beams with a 75% aggregate replacement with pumice. These beams were casted and tested twice under a two-point load application, once before strengthening and the other after that. The experimental results show that full strengthening of the beams along with their entire length, increase in load-carrying capacity by 75%, 113%, and 107% for normal concrete beam, (50% aggregate replacement) LWC beam, and (75% aggregate replacement) LWC beam respectively. While the middle-third strengthening of the beams shows an increase in load-carrying capacity by 64%, 72%, and 57% for normal concrete beam, (50% aggregate replacement) LWC aggregate beam, and (75% aggregate replacement) LWC beam respectively. The strength of the two types of LWC beams was almost the same and it is about 85% of the concrete beam with normal weight.

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