The Life-Span Prediction of Reinforcing Bars Corrosion of Self-Compacting Concrete

2011 ◽  
Vol 189-193 ◽  
pp. 4318-4324
Author(s):  
Yue Li ◽  
Chao Yan ◽  
Xiu Li Du ◽  
Yong Zhang ◽  
Qiao Lei
Keyword(s):  
Reinforced Concrete ◽  
Prediction Model ◽  
Life Span ◽  
Chloride Ion ◽  
Test Results ◽  
Reinforcing Bars ◽  
Prediction Formula ◽  
Self Compacting Concrete ◽  
Corrosion Condition ◽  
Chlorine Ions

Self-compacting concrete (SCC) has been used widely. However, the study of life-span prediction of self-compacting reinforced concrete is not enough under chloride ion corrosion condition， For the reinforcing bars corrosion that chlorine ions invade into SCC，the life-span prediction of Self-Compacting Concrete is the key issue. In this paper, the life-span prediction model of SCC structure under chloride ion corrosion condition is established and used to analyze the life-span prediction of SCC samples. Prediction results matched the test results very well, which shows the rationality of this prediction formula.

Experimental Study on the Structural Performance of Beam-Column Joints in Old Buildings without Designed Shear Reinforcement under Earthquake

2017 ◽  
Vol 902 ◽  
pp. 33-40
Author(s):  
Cong Thuat Dang ◽  
Ngoc Hieu Dinh
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Test Results ◽  
Shear Reinforcement ◽  
Reinforcing Bars ◽  
Reinforced Concrete Buildings ◽  
Concrete Buildings ◽  
Gravity Load ◽  
Load Beam

Old reinforced concrete buildings constructed around 1980’s in many developing countries have been designed against mainly gravity load. Beam-column joints in these buildings contain slightly or no shear reinforcement inside the panel zones due to the construction convenience, and are vulnerable to shear failure in beam-column joints under the action of earthquake loads, especially for the exterior beam-column joints. This experimental study aimed to investigate the seismic performance of five half-scale exterior beam-column joints simulating the joints in existing reinforced-concrete buildings with non-shear hoop details. The test results showed that the structural performances of the beam-column joints under earthquake including failure mode, load-drift ratio relationship, shear strain of the joints and energy dissipation are strongly affected by the amount of longitudinal reinforcing bars of beams.

Analysis and Design Recommendations for the Collapse of a Concrete Silo

2011 ◽  
Vol 250-253 ◽  
pp. 2877-2880 ◽  
Author(s):  
Guang Lin Yuan ◽  
Lu Dan Tian
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Structure Design ◽  
Test Results ◽  
Reinforcing Bars ◽  
Design Recommendations ◽  
Analysis And Design ◽  
The Future ◽  
Design And Construction

Accidents of the cement manufacturers’ reinforced concrete silo structures frequently occurred currently in China, because of quality problems, causing enormous losses. The collapse status of a cement raw meal silo is investigated. Combined with the test results of the location and spacing of silo wall’s reinforcing bars, concrete strength, cracks and defects, the reasons for collapse of silo wall are analyzed and design recommendations for concrete silo structures are made. This can give reference to reinforced concrete silo structure design and construction in the future.

Study on the Corrosion Performance of Reinforced Concrete by Using the Seawater Hot Rain Testing Equipment

2013 ◽  
Vol 699 ◽  
pp. 173-178
Author(s):  
Yue Li ◽  
Zhong Wei Gu ◽  
Xian Ming Qin
Keyword(s):  
Reinforced Concrete ◽  
Marine Environment ◽  
Rust Resistance ◽  
Chloride Ion ◽  
Crystalline Material ◽  
Test Results ◽  
Ion Permeability ◽  
Corrosion Performance ◽  
Different Types ◽  
Rust Inhibitor

In order to investigate the corrosion performance of reinforced concrete in the marine environment, the seawater hot rain testing (SHRT) equipment was used to imitate the marine environment and accelerate corrosion rate by circularly spraying seawater to the samples under high temperatures which can attain 70°C. The test results show that SHRT can accelerate the chloride ion permeability which can quickly investigate the corrosion performance of reinforced concrete. Different types of material admixtures have different influences on the corrosion performance of reinforcement concrete, and rust inhibitor and cementitious capillary crystalline material can improve the anti-rust resistance of reinforced concrete effectively.

Application of a Reinforced Self-Compacting Concrete Jacket in Damaged Reinforced Concrete Beams under Monotonic and Repeated Loading

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Constantin E. Chalioris ◽  
Constantin P. Papadopoulos ◽  
Constantin N. Pourzitidis ◽  
Dimitrios Fotis ◽  
Kosmas K. Sideris
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Small Diameter ◽  
Structural Response ◽  
Reinforced Concrete Beams ◽  
Repeated Loading ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Loading Test ◽  
Flexural Response

This paper presents the findings of an experimental study on the application of a reinforced self-compacting concrete jacketing technique in damaged reinforced concrete beams. Test results of 12 specimens subjected to monotonic loading up to failure or under repeated loading steps prior to total failure are included. First, 6 beams were designed to be shear dominated, constructed by commonly used concrete, were initially tested, damaged, and failed in a brittle manner. Afterwards, the shear-damaged beams were retrofitted using a self-compacting concrete U-formed jacket that consisted of small diameter steel bars and U-formed stirrups in order to increase their shear resistance and potentially to alter their initially observed shear response to a more ductile one. The jacketed beams were retested under the same loading. Test results indicated that the application of reinforced self-compacting concrete jacketing in damaged reinforced concrete beams is a promising rehabilitation technique. All the jacketed beams showed enhanced overall structural response and 35% to 50% increased load bearing capacities. The ultimate shear load of the jacketed beams varied from 39.7 to 42.0 kN, whereas the capacity of the original beams was approximately 30% lower. Further, all the retrofitted specimens exhibited typical flexural response with high values of deflection ductility.

scholarly journals Experimental Behavior of Concrete-Filled Steel Tubular Members Subjected to Lateral Loads

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Chengzhi Wang ◽  
Xin Liu ◽  
Pengfei Li
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bending Moment ◽  
Steel Tube ◽  
Test Results ◽  
Lateral Loads ◽  
Reinforcing Bars ◽  
Concrete Pile ◽  
Steel Bars ◽  
Concrete Model

The findings of an experimental study that was undertaken to investigate the performance of concrete-filled steel tubular members subjected to lateral loads are reported in this study. Columns of pure concrete, concrete with reinforcing bars, and two steel tube thicknesses were considered. Two different tests were conducted in this study. One test is used to research the performance of steel tube-reinforced concrete model piles under a lateral loading. The other test is used to research the effect of the depth of rock embedment for piles embedded in a foundation to simulate actual engineering applications in an experimental study. According to these test results, a detailed analysis was carried out on the relationships, such as the stress-strain and load-displacement relationships for the specimen. These tests show that the steel tube thickness and steel bars will significantly enhance the lateral bearing capacity and rigidity of the composite components. Additionally, the ultimate bending moment formula of a steel tube-reinforced concrete pile is deduced. The comparison of the calculated results with the experimental results shows that this formula is applicable for this type of pile foundation.

Exposure Test of FRP-Reinforced Concrete Structure in Temperate Marine Tide Zone

2012 ◽  
Vol 166-169 ◽  
pp. 538-542
Author(s):  
Ming Jin Chu ◽  
Zhi Juan Sun ◽  
Hui Chen Cui ◽  
Ke Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Test Results ◽  
Reinforced Concrete Structure ◽  
Freezing And Thawing ◽  
Concrete Member ◽  
Exposure Test ◽  
Reinforced Concrete Member ◽  
Marine Zone

Through exposure test of FRP-reinforced concrete member in littoral test area of temperate marine zone, the durability and constructional measures of FRP-reinforced concrete structure are investigated. The test results show that FRP shell on the surface of FRP-reinforced concrete member is effective in avoiding wave flush, freezing and thawing damage, preventing chloride ion corrosion and improving durability. On the other hand, reliable measures should be taken to protect concrete structures with no FRP shell on the surface. Based on above, the provided reference for evaluation durability of FRP-reinforced concrete structure, and proper constructional measures for FRP-reinforced concrete structure are presented.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

scholarly journals The Effect of a Corrosion Inhibitor on the Rehabilitation of Reinforced Concrete Containing Sea Sand and Seawater

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1480 ◽  
Author(s):  
Chonggen Pan ◽  
Xu Li ◽  
Jianghong Mao
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Inhibitor ◽  
Control Experiment ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Maximum Value ◽  
Steel Bar ◽  
Sea Sand ◽  
Chlorine Ions ◽  
Electrochemical Chloride Extraction

Concrete made with sea sand and seawater is rich in chlorine ions which are the main factors that induce corrosion of the reinforcement. In this study, an innovative method to rehabilitate reinforcement is presented; the concentrations of chloride ions and the corrosion inhibitor in concrete were measured. Electrochemical chloride extraction (ECE) was applied as a control experiment via using saturated Ca(OH)2 solution as an external electrolyte. Bidirectional electromigration (BIEM)technology combined with the corrosion inhibitor could not only remove the chloride ions but also protect the steel bar in concrete, and animidazoline inhibitor mixed in concrete is more effective than thetriethylenetetramine inhibitor due to the specific molecular structure. It was found that the optimum ratio of N/Cl reached the maximum value 3.3, when the concentration of inhibitor was 1. Meanwhile, the experimental results also revealed that the corrosion inhibitor and chloride ion concentrations reached necessary levels on the surface of the steel, and the corrosion inhibitor migrated effectively. Overall, the contents of imidazoline and triethylenetetramine inhibitor in seawater concrete are0.75% and 1%, respectively. The results demonstrate that the addition of the corrosion inhibitor and the application of bidirectional electromigration would effectively improve the durability of reinforced concrete containing sea sand and seawater.

scholarly journals Autonomous Corrosion Assessment of Reinforced Concrete Structures: Feasibility Study

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6825
Author(s):  
Woubishet Zewdu Taffese ◽  
Ethiopia Nigussie
Keyword(s):  
Reinforced Concrete ◽  
Feasibility Study ◽  
Concrete Structures ◽  
Chloride Ion ◽  
High Sensitivity ◽  
Reinforced Concrete Structures ◽  
Corrosion Condition ◽  
Rc Structures ◽  
Corrosion Assessment ◽  
Use Of Internet

In this work, technological feasibility of autonomous corrosion assessment of reinforced concrete structures is studied. Corrosion of reinforcement bars (rebar), induced by carbonation or chloride penetration, is one of the leading causes for deterioration of concrete structures throughout the globe. Continuous nondestructive in-service monitoring of carbonation through pH and chloride ion (Cl−) concentration in concrete is indispensable for early detection of corrosion and making appropriate decisions, which ultimately make the lifecycle management of RC structures optimal from resources and safety perspectives. Critical state-of-the-art review of pH and Cl− sensors revealed that the majority of the sensors have high sensitivity, reliability, and stability in concrete environment, though the experiments were carried out for relatively short periods. Among the reviewed works, only three attempted to monitor Cl− wirelessly, albeit over a very short range. As part of the feasibility study, this work recommends the use of internet of things (IoT) and machine learning for autonomous corrosion condition assessment of RC structures.

Assessment of CSA A23.3 structural integrity requirements for two-way slabs

2012 ◽  
Vol 39 (4) ◽  
pp. 351-361 ◽  
Author(s):  
Farshad Habibi ◽  
Erin Redl ◽  
Michael Egberts ◽  
William D. Cook ◽  
Denis Mitchell
Keyword(s):  
Reinforced Concrete ◽  
Structural Integrity ◽  
Concrete Slab ◽  
Punching Shear ◽  
Slab Thickness ◽  
Test Results ◽  
Reinforcing Bars ◽  
Reasonable Estimate ◽  
Reinforced Concrete Slab ◽  
Rectangular Columns

This paper investigates the post-punching behaviour of reinforced concrete slab–column connections with a goal of providing adequate structural integrity reinforcement. The test results of seven interior slab–column connections are presented. A study was made of the effects of slab thickness, length of structural integrity reinforcing bars, distribution of structural integrity reinforcement in slabs with rectangular columns, and the placement of structural integrity reinforcement in slabs with drop panels. Results from this test series and other researchers were compared with predictions using the CSA A23.3-04 design equations for both punching shear and post-punching resistance. The test results demonstrated that the provision of structural integrity reinforcement in accordance with the requirements of CSA A23.3-04 resulted in significant post-punching resistance and the design equations provide a reasonable estimate of this resistance.

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