Flexural behaviour of hybrid fibre reinforced concrete beams made with various packing factors and fine to total aggregate ratio

The objective of this study is to investigate the flexural behavior of M30 grade PSCC, GFRSCC, SFRSCC and HFRSCC beams made with PF=1.12 and s/a=0.53 and PF=1.14 and s/a=0.57 to understand the effect of copper slag as partial replacement of fine aggregate on its deflection characteristics and cracking behaviour. The yield and ultimate load taken by HFRSCC beams made with optimum PF and s/a ratios are higher than the conventional RCC beam elements. The deflections at centre at failure in HFRSCC beams made with optimum PF and s/a ratios were more than that of conventional beams. This shows improvement in ductility of HFRSCC beams. First crack formation was delayed in M30 grade HFRSCC beams due to dense micro structure with low pore fraction and reduced pore size due to which fatigue strength is increased which in turn increases the time taken for first crack occurrence and thereby increasing the load carrying capacity. The deflection at the mid span decreased in HFRSCC beams which shows that the flexural stiffness of the elements increases thereby reducing the structural member’s deformability, increasing strength and hence controlling deflection.

Download Full-text

Flexural Behavior of SCC with Copper Slag as Partial Replacement of Fine Aggregate

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.a2330.059120 ◽

2020 ◽

Vol 9 (1) ◽

pp. 1139-1145

Keyword(s):

Copper Slag ◽

Flexural Behavior ◽

Partial Replacement ◽

Fine Aggregate ◽

Flexural Test ◽

Strain Pattern ◽

Fine Aggregates ◽

Concrete Placement ◽

Day By Day ◽

Construction Practice

Natural fine aggregates are becoming more limited, and their production and consignment are turning out hard day by day. Therefore, the production of concrete needs to turn into eco-friendly construction practice. Self-Compacting Concrete (SCC) self-consolidates itself without any external vibration, and subsequently it quickens the concrete placement process and decreases the labor demands. In this study, the Flexural behavior of the SCC was studied. Reinforced SCC beam specimens were cast and tested in laboratories. The flexural behavior of SCC with copper slag as replacement for sand is delimited with the flexural test on beam specimens by examining the factors like deflection, flexural strength, crack pattern and strain pattern.

Download Full-text

Flexural Behaviour Of Reinforced Concrete Beams Containing Expanded Glass As Lightweight Aggregates

Slovak Journal of Civil Engineering ◽

10.1515/sjce-2015-0017 ◽

2015 ◽

Vol 23 (4) ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Jamal Khatib ◽

Adrian Jefimiuk ◽

Sammy Khatib

Keyword(s):

Reinforced Concrete ◽

Carrying Capacity ◽

Concrete Beam ◽

Concrete Beams ◽

Reinforced Concrete Beams ◽

Fine Aggregate ◽

Load Carrying Capacity ◽

Flexural Behaviour ◽

Structural Concrete ◽

Load Carrying

Abstract The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand) replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume) expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.

Download Full-text

Experimental Study on Flexural Strength of Reinforced Concrete Beam Exposed to Acid Deposition in the Laboratory

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.94-96.1494 ◽

2011 ◽

Vol 94-96 ◽

pp. 1494-1499

Author(s):

Ying Fang Fan ◽

Da Wei Wang ◽

Shi Yi Zhang

Keyword(s):

Reinforced Concrete ◽

Acid Rain ◽

Carrying Capacity ◽

Concrete Beams ◽

Reinforced Concrete Beams ◽

Flexural Behavior ◽

Load Carrying Capacity ◽

The Real ◽

Artificial Rainfall ◽

Load Carrying

In this study, the flexural behavior of the reinforced concrete beams attacked by acid rain environment is investigated. The objective is to discover the deterioration mechanism of the concrete beams servicing in the acid rain environment. An artificial rainfall device was designed. Eleven reinforced concrete beams, 120mm×200mm in cross-section were prepared in the laboratory. Three accelerating corrosion methods, which inclusive of immersion method, dry-wet cycle method, and artificial rainfall method, were applied to simulate the action of the real acid rain respectively. The acid solutions with pH level 1.5 and 2.5 were prepared by the mixture of sulfate and nitric acid solution respectively. One of the beams was tested in the natural condition to serve as reference; the remaining ten beams were tested after being exposed to the simulated acid environments for certain periods. Ultrasonic technology was applied to evaluate the damage depth and the compressive strength of the concrete. Dynamic test was applied to estimate the integrity of the beam. Three-point bending tests were performed to investigate the load carrying capacity of the beams. Mechanical properties of concrete and load carrying capacity of the beams exposed to different accelerated corrosion methods are obtained and compared. It is illustrated that the designed artificial device is efficient to simulate the real acid rainfall. It is shown that the strength of concrete, frequency and ultimate load of the beams, have a direct relationship to the damage degree of the beams.

Download Full-text

Flexural Behavior of Damaged Lightweight Reinforced Concrete Beams Strengthened by CFRP

Journal of Engineering Research ◽

10.36909/jer.v9iicrie.11647 ◽

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.

Download Full-text

Effect of Copper Slag as a Fine Aggregate on the Durability Characteristics of High-Performance Concrete (HPC) Containing Silica Fume

Journal of Advanced Research in Civil and Environmental Engineering ◽

10.24321/2393.8307.202002 ◽

2020 ◽

Vol 07 (02) ◽

pp. 1-10

Author(s):

Rizwan Ahmad Khan ◽

Keyword(s):

Silica Fume ◽

High Performance ◽

High Performance Concrete ◽

Copper Slag ◽

Chloride Penetration ◽

Interfacial Transition Zone ◽

Fine Aggregate ◽

Fresh Properties ◽

Fine Aggregates ◽

Effect Of Copper

This paper investigates the fresh and durability properties of the high-performance concrete by replacing cement with 15% Silica fume and simultaneously replacing fine aggregates with 25%, 50%, 75% and 100% copper slag at w/b ratio of 0.23. Five mixes were analysed and compared with the standard concrete mix. Fresh properties show an increase in the slump with the increase in the quantity of copper slag to the mix. Sorptivity, chloride penetration, UPV and carbonation results were very encouraging at 50% copper slag replacement levels. Microstructure analysis of these mixes shows the emergence of C-S-H gel for nearly all mixes indicating densification of the interfacial transition zone of the concrete.

Download Full-text

Flexural Performance of Reinforced Concrete Built-up Beams with SIFCON

Engineering and Technology Journal ◽

10.30684/etj.v38i5a.501 ◽

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.

Download Full-text

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

Journal of Engineered Fibers and Fabrics ◽

10.1177/15589250211020311 ◽

2021 ◽

Vol 16 ◽

pp. 155892502110203

Author(s):

Mohammad Iqbal Khan ◽

Galal Fares ◽

Yassir Mohammed Abbas ◽

Wasim Abbass ◽

Sardar Umer Sial

Keyword(s):

Strain Hardening ◽

Environmental Conditions ◽

Carrying Capacity ◽

Flexural Behavior ◽

Load Carrying Capacity ◽

Rc Beams ◽

Curing Conditions ◽

Flexural Members ◽

Load Carrying ◽

Curing Regime

Strain-hardening cement-based composites (SHCC) have recently been developed as repair materials for the improvement of crack control and strength of flexural members. This work focuses on strengthening and flexural enhancement using SHCC layer in tensile regions of flexural members under three different curing conditions. The curing conditions simulate the effect of different environmental conditions prevailing in the central and coastal regions of the Arabian Peninsula on the properties of SHCC as a retrofitting material. In this investigation, beams with SHCC layer were compared to control beams. The beams with SHCC layer of 50-mm thickness were cast. The results revealed that the flexural behavior and the load-carrying capacity of the normal concrete beam specimens under hot and dry environmental conditions were significantly reduced, lowering the ductility of the section. However, compressive strength is comparatively unaffected. Similarly, the hot curing conditions have also led to a notable reduction in the loading capacity of the beam with SHCC layer with a slight effect on its stiffness. On the other hand, steam-curing conditions have shown improvement in load-carrying capacity and a reduction in section ductility of the beam with SHCC layer. It was found that the structural unit retrofitted with SHCC layer was a curing-regime dependent as the tensile and strain-hardening properties of SHCC are highly sensitive to the alteration in the cement hydration process. A normal curing regime was found effective and satisfying the practical, cost, and performance requirements. Accordingly, a normal curing regime could be implemented to retrofit reinforced concrete (RC) beams with SHCC layers as recommended in the study.

Download Full-text

Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads

10.20944/preprints202201.0041.v1 ◽

2022 ◽

Author(s):

Paolo Foraboschi

Keyword(s):

Reinforced Concrete ◽

Carrying Capacity ◽

Concrete Beams ◽

Shear Capacity ◽

Reinforced Concrete Beams ◽

Load Carrying Capacity ◽

Reinforced Concrete Structure ◽

Concentrated Loads ◽

Concentrated Load ◽

Load Carrying

Renovation, restoration, remodeling, refurbishment, and retrofitting of build-ings often imply modifying the behavior of the structural system. Modification sometimes includes applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. For a reinforced concrete structure, the new condition causes a beam to bear a concentrated load with the crack pattern that was produced by the distributed loads that acted in the past. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum around the midspan. But around the midspan, the cracks are vertical or quasi-vertical, and no inclined bar is present. So, the actual shear capacity around the midspan not only is low, but also can be substantially lower than the new demand. In order to bring the beam capacity up to the demand, fiber-reinforced-polymer composites can be used. This paper presents a design method to increase the concentrated load-carrying capacity of reinforced concrete beams whose load distribution has to be changed from distributed to concentrated, and an analytical model to pre-dict the concentrated load-carrying capacity of a beam in the strengthened state.

Download Full-text