scholarly journals Behavior of Reactive Powder Concrete Beams Exposed to Fire

2021 ◽  
Vol 14 (4) ◽  
pp. 1-10
Author(s):  
Mahmoud Ahmed Ali ◽  
Aboelwafa Elthakeb ◽  
Usama Mohamed ◽  
Mohamed Taha Noaman
Keyword(s):  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Service Load ◽  
Maximum Crack ◽  
Temperature Levels ◽  
Fire Flame ◽  
Reactive Powder ◽  
And Behavior ◽  
The Relationship

In this paper, the effect of direct fire flame and steel fiber ratio on some mechanical properties and behavior of the relationship between load and deflection of rectangular reinforced concrete beams under the influence of fire exposure was studied. Concrete specimens were exposed to fire at temperatures ranging from (25- 400 ºC). Three temperature levels of (200, 300, 400 ºC) where chosen for exposure duration of 2.0 hours. After conducting the test, it was found that increasing the proportion of steel fibers in percentages 0.5% to 1% and 1.5% decreases the mid-span deflection at service load by 33%, 50% and 37.5 and increases the ultimate load by 36.36%, 41.6% and 53% respectively. After the beams are exposed to fire, it was noticed that the maximum crack width increases with increasing fire temperature.

scholarly journals DUCTILITY RESPONSE OF HYBRID FIBRE REINFORCED CONCRETE BEAMS

2018 ◽  
pp. 174-179 ◽  
Author(s):  
Eswari Natarajan
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Fibre Volume ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Hybrid Fibre ◽  
Service Load ◽  
Strength And Ductility

Abstract: The effect of fibre content on the Strength and ductility behaviour of hybrid fibre reinforced concrete (HFRC) beams having different fibre volume fractions was investigated. The parameters of this investigation included service load, ultimate load, service load deflection, ultimate load deflection, crack width, deflection ductility and energy ductility. The fibre volume fraction (Vf) ranged from 0.0 to 2.0 percent. Steel and polyolefin fibres were combined in different proportions and their impact on the above parameters was studied. The ductile response of hybrid fibre reinforced concrete beams was compared with that of control beam. The test results show that addition of 2.0 percent by volume of hybrid fibres improve the strength and ductility appreciably. Empirical expressions for predicting the strength and ductility of hybrid fibre reinforced concrete (HFRC) are proposed based on regression analysis. A close agreement has been obtained between the predicted and experimental results.

scholarly journals Structural Behavior of Continuous Steel-Reactive Powder Concrete Composiate Beams Under Repeated Loads

2018 ◽  
Vol 7 (4.19) ◽  
pp. 843
Author(s):  
Rasha Yassien Dakhil ◽  
Mustafa B. Dawood
Keyword(s):  
Ultimate Load ◽  
Concrete Beams ◽  
Numerical Models ◽  
Experimental Tests ◽  
Reactive Powder Concrete ◽  
Mode Of Failure ◽  
Reactive Powder ◽  
And Behavior ◽  
Push Out ◽  
Repeated Loads

A study for the continuous composite steel-reactive powder concrete beams under repeated loads were executed experimentally and analytically. In the experimental part, six continuous composite sections were constructed as test beams. "The‘“decks slab concretes"was connected tos steel I-beams by headed steel studs welded to the top flanges“ofs“thes‘‘steel I-beams.“T,he dimensions“ of “the“ deck slab is (2200×250×80mm), while the type of I-beam is (IPE 140) with length of (2200mm). For the present work, the experimental work includes also examining the shear in the links by creating two models (push out) and tested to determine the properties and behavior of the studs. The behavior of the studs were conducted by"getting load-slip curves. In the part of the,oretical,‘‘.tested beams.was numericallysmodeled then analyzed using thesfinite element method.‘“Thes“numerical models were carried out in three dimensionss bys“the software package (ANSYS 16.1). Verifi,cationsof thesnumericalsresults“was donesbyscompari,ngs thems with the experimentals results. “Thesresultssof thesfiniteselementsanalysissshowed good agreements‘with the results ofsthe experimental tests. The maximumsandsminimum difference‘‘in ultimate loa,ds for beams‘‘ were (5.85% and 1.33%) respectively.  The results show that stiffenerssof beamssandsstrengthening with CFRP shall increase the ultimate load capacity‘and affects on‘‘mode of failure“ of theses beams.‘  

scholarly journals Strength and Ductility of Bubbled Wide Reinforced Concrete Beams with Diverse Types of Shear Steel Plates

2018 ◽  
Vol 7 (4.20) ◽  
pp. 502 ◽  
Author(s):  
Amer Mohamed Ibrahim ◽  
Ahmed Abdullah Mansor ◽  
Wissam D. Salman ◽  
Mohammed Jaafar Hamood
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Good Alternative ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Cross Sectional ◽  
Service Load ◽  
Different Types ◽  
Strength And Ductility

This paper presents an experimental investigation on the strength of bubbled wide reinforced concrete beams with different types of shear steel plates. Eight specimens with dimensions of 215x560x1800mm were investigated. The studied variables deal with replacement of 10mm stirrups diameter stirrups spaced at 125mm by shear steel plates having equivalent cross-sectional area for stirrups at mid legs height with circular opening of different thicknesses (3, 4 and 5mm). Four specimens were without any bubbles and the others with bubbles. This study showed that the shear steel plates is a good alternative for replacing the stirrups and gives increasing in yield, ultimate load and deflection (at service load) with 5% , 15% and 9% on the average when using the bubbles. Without using bubbles, the aspect ratio of shear steel plates bounded between the boundaries 4.5 to 8 gave increased the ductility by 36%. Using the bubbles in specimens was decreased 4.7% from the total weight of specimens. ACI 318-14(1) and EC 2(2) codes give a predicted deflection more than that obtained from experimental results by 16% on the average and by 24% when using bubbles.    

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 Experimental investigation on the post-fire performance of reactive powder concrete columns

2021 ◽  
Vol 30 (2) ◽  
pp. 315-326
Author(s):  
Mohammed Kadhum ◽  
Mustafa Abdulraheem ◽  
Yousif Funfakh ◽  
Michaela Gkantou ◽  
Zainab Mahdi ◽  
...  
Keyword(s):  
Failure Mode ◽  
Shear Failure ◽  
Ultimate Load ◽  
Concrete Columns ◽  
Maximum Temperature ◽  
Reactive Powder Concrete ◽  
Fire Performance ◽  
Temperature Levels ◽  
Fire Flame ◽  
Reactive Powder

The increased use of reactive powder concrete (RPC) in concrete structures has attracted attention towards the structural behavior of RPC in fires. This work examines experimentally the performance of RPC and NSC columns subjected to 25% of the ultimate load and exposed to direct fire flame for a period of 30 and 60 min at various temperature levels. The paper aims to evaluate the maximum temperature level and fire duration that can be withstood by this type of concrete columns. The results show that the failure mode of RPC columns without reinforcement is a sudden shear failure, whereas the failure mode of reinforced RPC columns is a crushing failure with rupture of certain ties. The RPC columns at high temperatures spall intensively; additionally, the ultimate strength clearly decreases compared to the NSC columns at the same conditions.

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 Built-up Beams with SIFCON

2020 ◽  
Vol 38 (5A) ◽  
pp. 669-680
Author(s):  
Ghazwan K. Mohammed ◽  
Kaiss F. Sarsam ◽  
Ikbal N. Gorgis
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Conventional Concrete ◽  
Flexural Performance ◽  
Load Carrying ◽  
Fiber Concrete

The study deals with the effect of using Slurry infiltrated fiber concrete (SIFCON) with the reinforced concrete beams to explore its enhancement to the flexural capacity. The experimental work consists of the casting of six beams, two beams were fully cast by conventional concrete (CC) and SIFCON, as references. While the remaining was made by contributing a layer of SIFCON diverse in-depth and position, towards complete the overall depths of the built-up beam with conventional concrete CC. Also, an investigation was done through the control specimens testing about the mechanical properties of SIFCON. The results showed a stiffer behavior with a significant increase in load-carrying capacity when SIFCON used in tension zones. Otherwise high ductility and energy dissipation appeared when SIFCON placed in compression zones with a slight increment in ultimate load. The high volumetric ratio of steel fibers enabled SIFCON to magnificent tensile properties.

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 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%.   

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