Influence of Reinforcement Ratios on Concrete Fracture Parameters

2013 ◽  
Vol 438-439 ◽  
pp. 224-228
Author(s):  
Xiang Qian Fan ◽  
Shao Wei Hu ◽  
Jun Lu
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
Relevant Literature ◽  
Reinforced Concrete Beams ◽  
Concrete Fracture ◽  
Propagation Length ◽  
Three Point Bending ◽  
Whole Process ◽  
Fracture Parameters ◽  
Initial Fracture

Based on double-K fracture model, adopt three-point bending beam which has been recommended by RILEM, the fracture properties of three groups reinforced concrete beams were studied. Refer to the relevant literature, fracture parameters of reinforced concrete three-point bending beams are examined. Through the analysis of whole process of crack propagation of reinforced concrete three-point bending beams, the results show that the reinforcement ratios can't preventing the cracking effectively, but can increase the maximum loads, thus improving the relative toughness; the precritical crack propagation length relative values show a linearly increasing trend with the increase of reinforcement ratios; the initial fracture toughness is not affected by the reinforcement ratios, but the unstable toughness has little effects by the reinforcement ratios.

Shear strength of disturbed regions with corroded stirrups in reinforced concrete beams

2010 ◽  
Vol 37 (8) ◽  
pp. 1045-1056 ◽  
Author(s):  
Christopher Suffern ◽  
Ahmed El-Sayed ◽  
Khaled Soudki
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Corrosion Damage ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Accelerated Corrosion ◽  
Damage Level ◽  
Three Point Bending ◽  
Shear Span

This paper reports experimental data on the structural performance of disturbed regions in reinforced concrete beams with corrosion damage to the embedded steel stirrups. A total of 15 reinforced concrete beams were constructed and tested. The test beams were 350 mm deep, 125 mm wide, and 1850 mm long. The beams were tested in three-point bending under a simply supported span of 1500 mm. Nine beams had the embedded stirrups subjected to accelerated corrosion. The test variables were the corrosion damage level and the shear span-to-depth ratio. The test results indicated that the corroded beams exhibited reduced shear strength in comparison to the uncorroded control specimens. The shear strength reduction was up to 53%. Furthermore, the reduction in shear strength due to the corrosion was found to be greater at smaller shear span-to-depth ratios.

scholarly journals Effect of loading rate on flexural behavior of concrete and reinforced concrete beams

2021 ◽  
Vol 15 (3) ◽  
pp. 136-143
Author(s):  
Nguyen Trung Hieu ◽  
Nguyen Van Tuan
Keyword(s):  
Reinforced Concrete ◽  
Loading Rate ◽  
Plain Concrete ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Displacement Curve ◽  
Rc Beams ◽  
Three Point Bending ◽  
Loading Rates ◽  
Hydraulic Servo

The elasto-plastic characteristics of plain concrete are inevitably affected by the loading rate. This paper presents an experimental investigation on the effect of loading rate on flexural behavior of concrete and reinforced concrete (RC) beams, which was carried out with Walter+bai electro-hydraulic servo system. Three-point bending tests on 100 × 100 × 400 mm prismatic concrete samples and 80 × 120 × 1100 mm RC beams with different displacement controlled loading rates of 0.01 mm/min, 0.1 mm/min, and 3 mm/min were imposed. Based on the test results, the effects of loading rates on the load-displacement curve, cracking, and ultimate load-carrying capacities of RC beams were evaluated.

Full-Field Displacement and Strain Measurement: Application of Digital Image Correlation to Reinforcement Corrosion Induced Concrete Fracture and Cover Cracking

2015 ◽  
Vol 738-739 ◽  
pp. 889-892
Author(s):  
Qiang Li ◽  
Hong Fa Yu ◽  
Jing Tong
Keyword(s):  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Test Method ◽  
Image Correlation ◽  
Concrete Fracture ◽  
Reinforcement Corrosion ◽  
Full Field ◽  
Rc Structures ◽  
Whole Process ◽  
Cover Cracking

Cracking of the cover concrete due to steel corrosion is considered as one of the major issues of durability of reinforced concrete (RC) structures. This paper tentatively studies the feasibility of DIC to reinforcement corrosion induced concrete fracture and cover cracking measurement. Advantages and limitations of DIC-based non-contact full-field measurement for corrosion induced concrete fracture and cover cracking are discussed. Drawbacks in this test need improvement are pointed out and test method for further study of whole process of simulating the real reinforced concrete cracking is put forward.

scholarly journals BEHAVIOUR OF REINFORCED CONCRETE BEAMS WITHOUT STIRRUPS SUBJECTED TO STEEL REINFORCEMENT CORROSION

2016 ◽  
Vol 22 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Rizwan AZAM ◽  
Ahmed K. EL-SAYED ◽  
Khaled SOUDKI
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Longitudinal Reinforcement ◽  
Rc Beams ◽  
Test Results ◽  
Structural Behaviour ◽  
Three Point Bending ◽  
Load Carrying ◽  
Crack Widths

The effect of corrosion on the structural behaviour of reinforced concrete (RC) beams without stirrups was experimentally investigated. A total of seven medium-scale RC beams without stirrups were constructed. The beams measured 150 mm wide, 250 mm deep and 1700 mm long. The test variables included: three different longitudinal reinforcement ratios (0.91%, 1.21%, and 1.82%) and two different corrosion levels (3% and 10%). Four beams were subjected to artificial corrosion whereas three beams acted as control un-corroded. Following the corrosion phase, all beams were tested to failure in three point bending. Corrosion crack widths and cracking patterns were recorded at different stages of corrosion. The effect of different longitudinal reinforcement ratios on the rate of corrosion was observed. Test results revealed that the beams with higher reinforcement ratios experienced slower corrosion rate compared to beams with lower reinforcement ratios. All control beams failed in shear whereas corroded beams failed in bond. There was a significant reduction in the load carrying capacity of the corroded beams without stirrups compared to the control beams.

Propagation Behavior of Main Crack in Reinforced Concrete Beams Strengthened with CFRP under Cyclic Bending Load

2013 ◽  
Vol 535-536 ◽  
pp. 205-208
Author(s):  
Zheng Wei Li ◽  
Pei Yan Huang ◽  
Hao Zhou
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
Main Crack ◽  
Fatigue Behavior ◽  
Propagation Rate ◽  
Reinforced Concrete Beams ◽  
Rc Beam ◽  
Cyclic Bending ◽  
Propagation Behavior ◽  
Bending Load

Fatigue behavior of reinforced concrete (RC) beam can be improved by externally bonded fiber reinforced polymer (FRP). However, propagation behavior of a crack on the RC beam will have serious effect on the fatigue life of the beam strengthened with FRP. In this paper, a finite element (FE) procedure was developed to analysis the stress intensity factor (SIF) of the main crack and an experimental study was conducted to investigate the propagation rate of the main crack of the RC beam strengthened with carbon fiber laminate (CFL) under cyclic bending load. The FE analysis results show that the SIF near the main crack tip increases at the beginning and then decreases with the fatigue crack propagation. When relative crack length α is equal to 0.3, the SIF is maximum. When α approaches 0.75, the SIF approaches zero. A total of 3 RC beams strengthened with CFL were tested. The experimental results show that it is possible to divide the process of the crack propagation into three distinct phases, including crack initiation and then quickly propagation, stable propagation and then rest and unstable propagation. A semi-empirical equation based on the Paris Law was developed to predict the crack propagation rate.

Effect of Crack-Depth Ratio on Double-K Fracture Parameter of Reinforced Concrete

2012 ◽  
Vol 226-228 ◽  
pp. 937-941 ◽  
Author(s):  
Shao Wei Hu ◽  
Zheng Xiang Mi ◽  
Jun Lu
Keyword(s):  
Fracture Toughness ◽  
Reinforced Concrete ◽  
Crack Propagation ◽  
Crack Depth ◽  
Fracture Parameter ◽  
Propagation Process ◽  
Three Point Bending ◽  
Depth Ratio ◽  
Crack Propagation Process ◽  
Crack Depth Ratio

In order to study the influence of the crack-depth ratio on reinforced concrete fracture parameters and the resistance of the reinforcing bar to crack propagation in concrete, the fracture tests were carried on by using four groups three-point bending specimens with initial crack-depth ratios of 0.2, 0.3, 0.4 and 0.5 in this paper. An analytical model was presented to calculate fracture toughness of reinforced concrete by analyzing crack propagation process of the three-point bending beams. The formula of calculating effective crack length of reinforced concrete was established. The research results show that the double-K criterion can be used for describing crack propagation process of reinforced concrete by introducing fracture toughness, which is suitable for reinforced concrete. Initiation fracture toughness and unstable fracture toughness of reinforced concrete slowly increase with the increase of crack-depth ratio, which is different from the properties of ordinary concrete. The reinforced can improve the ductility of concrete obviously and inhibit the rate of crack propagation well.

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