scholarly journals Evaluating the Early-Age Crack Induction in Advanced Reinforced Concrete Pavement Using Partial Surface Saw-Cuts

2021 ◽  
Vol 11 (4) ◽  
pp. 1659
Author(s):  
Muhammad Kashif ◽  
Ahsan Naseem ◽  
Nouman Iqbal ◽  
Pieter De Winne ◽  
Hans De Backer
Keyword(s):  
Reinforced Concrete ◽  
Concrete Pavement ◽  
Early Age ◽  
Fe Model ◽  
Induction Method ◽  
Rigid Pavement ◽  
Partial Length ◽  
Steel Bar ◽  
Steel Bars ◽  
Cracking Characteristics

The technological innovation of continuously reinforced concrete pavement (CRCP) that contains a significantly reduced amount of reinforcement and the same fundamental behavior as CRCP is called advanced reinforced concrete pavement (ARCP). This new concept of a rigid pavement structure is developed to eliminate unnecessary continuous longitudinal steel bars of CRCP by using partial length steel bars at predetermined crack locations. In Belgium, partial surface saw-cuts are used as the most effective crack induction method to eliminate the randomness in early-age crack patterns by inducing cracks at the predetermined locations of CRCP. The reinforcement layout of ARCP is designed based on the distribution of steel stress in continuous longitudinal steel bar in CRCP and the effectiveness of partial surface saw-cuts as a crack induction method. The 3D finite element (FE) model is developed to evaluate the behavior of ARCP with partial surface saw-cuts. The early-age crack characteristics in terms of crack initiation and crack propagation obtained from the FE simulation are validated with the field observations of cracking characteristics of the CRCP sections in Belgium. The finding indicates that there is fundamentally no difference in the steel stress distribution in the partial length steel bar of ARCP and continuous steel bar of CRCP. Moreover, ARCP exhibits the same cracking characteristics as CRCP even with a significantly reduced amount of continuous reinforcement.

Early-age cracking behavior of advanced reinforced concrete pavement under environmental loading

2021 ◽  
Author(s):  
Muhammad Kashif ◽  
Ahsan Naseem ◽  
Nouman Iqbal ◽  
Pieter De Winne ◽  
Hans De Backer
Keyword(s):  
Reinforced Concrete ◽  
Concrete Pavement ◽  
Early Age ◽  
Fe Model ◽  
Induction Method ◽  
Rigid Pavement ◽  
Cracking Behavior ◽  
Partial Length ◽  
Steel Bars ◽  
Cracking Characteristics

<p>The technological innovation of continuously reinforced concrete pavement (CRCP) that contains a significantly reduced amount of reinforcement and the same fundamental behaviour as CRCP is called advanced reinforced concrete pavement (ARCP). This new concept of a rigid pavement structure is developed to eliminate unnecessary continuous longitudinal steel bars of CRCP by using partial length steel bars at predetermined crack locations. In Belgium, partial surface saw-cuts are used as the most effective crack induction method to eliminate the randomness in early-age crack patterns by inducing cracks at the predetermined locations of CRCP. The reinforcement layout of ARCP is designed based on the distribution of steel stress in continuous longitudinal steel bar in CRCP and the effectiveness of partial surface saw-cuts as a crack induction method. The 3D finite element (FE) model is developed to evaluate the behaviour of ARCP with partial surface saw-cuts. The early-age crack characteristics in terms of crack initiation and crack propagation obtained from the FE simulation are validated with the field observations of cracking characteristics of the CRCP sections in Belgium. The finding indicates that ARCP exhibits the same cracking characteristics as CRCP even with a significantly reduced amount of continuous reinforcement.</p>

Numerical evaluation of horizontal cracking potential in continuously reinforced concrete pavement under varying saw-cut depths

2021 ◽  
Author(s):  
Muhammad Kashif ◽  
Amelie Outtier ◽  
Muhammad Wisal Khattak ◽  
Pieter De Winne ◽  
Hans De Backer
Keyword(s):  
Reinforced Concrete ◽  
Tensile Stress ◽  
Transverse Crack ◽  
Flow Analysis ◽  
Field Trials ◽  
Concrete Pavement ◽  
Early Age ◽  
Fe Model ◽  
Cracking Potential ◽  
Steel Bar

<p>The objective of this study is to evaluate the horizontal cracking potential in terms of vertical tensile stress development near longitudinal steel bar in the continuously reinforced concrete pavement (CRCP). For this purpose, a three-dimensional (3D) finite element (FE) model of the CRCP segment with partial surface saw-cuts has been developed using the FE tool Diana 10.3. The early-age behaviour of CRCP subjected to external varying temperature field condition has been evaluated by using the staggered structural-flow analysis. The characteristics of the early-age crack pattern in terms of crack initiation and crack propagation obtained from the FE model are compared with the field observations of cracking developments on the CRCP sections in Belgium. The FE results indicate that the vertical tensile stress in concrete near the longitudinal steel bar develops at the transverse crack interface. It translates that the horizontal crack perpendicular to the vertical concrete stress can initiate from the transverse crack depending on the magnitude of stress against developing concrete tensile strength. It has also been observed that the deeper the saw-cut, the larger the magnitude of vertical tensile stress and the higher incident of horizontal cracking. Moreover, the developed 3D FE model can be further used to optimize the early-age behaviour of CRCP in advance of costly field trials.</p>

scholarly journals Effect of Imidazoline Inhibitor on the Rehabilitation of Reinforced Concrete with Electromigration Method

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 398 ◽  
Author(s):  
Chonggen Pan ◽  
Jianghong Mao ◽  
Weiliang Jin
Keyword(s):  
Reinforced Concrete ◽  
Extraction Efficiency ◽  
Corrosion Potential ◽  
Steel Bar ◽  
Chloride Migration ◽  
Significant Difference ◽  
Steel Bars ◽  
Novel Method ◽  
Electrochemical Chloride Extraction ◽  
High Chloride

Steel bars embedded in reinforced concrete are vulnerable to corrosion in high chloride environments. Bidirectional electromigration rehabilitation (BIEM) is a novel method to enhance the durability of reinforced concrete by extracting chloride out of concrete and introducing an inhibitor to the surface of the steel bar under the action of an electric field. During the migration process, a higher ionization capacity of the inhibitor with a symmetrical molecular structure was introduced. A new imidazoline inhibitor was, therefore, employed in this study due to its great ionization capacity. The effect of imidazoline and triethylenetetramine inhibitor on chloride migration, corrosion potential, and strength of concrete were explored. The research results showed that the effect of chloride extraction and electrochemical chloride extraction made no significant difference on the surface of the concrete, where chloride extraction efficiency was more than 70%, and the chloride extraction efficiency was more than 90% around the location of the steel. while a dry-wet cycle test, the potential of concrete increased by about 200 mV by mixing imidazoline inhibitor. The imidazoline inhibitor was found to be effective at facilitating chloride migration and ameliorating corrosion, meanwhile, it had a negligible impact on the concrete’s strength.

Full-Scale Evaluation of an Innovative Joint Design between Adjacent Box Beams

2020 ◽  
Vol 2674 (2) ◽  
pp. 33-44 ◽  
Author(s):  
Zhengyu Liu ◽  
Brent M. Phares ◽  
Weizhuo Shi ◽  
Behrouz Shafei
Keyword(s):  
Small Scale ◽  
Early Age ◽  
Fe Model ◽  
Joint Design ◽  
Box Beam ◽  
Steel Bars ◽  
Longitudinal Joint ◽  
Box Beams ◽  
Longitudinal Joints ◽  
And Performance

The longitudinal joints on adjacent precast, prestressed box beams used in bridge construction are vulnerable to cracking. These cracks provide a direct path for water and deleterious agents to enter the structural system, causing corrosion of the embedded steel bars and tendons. To avoid significant maintenance costs, safety concerns, or both, an innovative longitudinal joint between two adjacent box beams was designed in the current study. This joint is 6½ in. wide with roughened surfaces, filled with shrinkage compensating concrete and reinforced by steel bars. The joint was evaluated on a small-scale basis and satisfactory performance was obtained in resisting early-age cracks. In the current paper, the joint design is further evaluated through experiments on a 31 ft long specimen during the joint’s early age, and when it is subjected to multiple levels of cyclic loads. A finite element (FE) model that is capable of simulating the early-age concrete hardening was also developed and validated against the experimental data. The early-age, time-dependent stress development in the joint and at the interface of the joint and box beam was investigated using the FE model. Based on the results of laboratory tests and FE simulations, the innovative joint was found to remain crack free without the utilization of a shear key or transverse post-tensioning. The “compression-dominate” joint created by the expansive joint material and transverse reinforcing bars across the interface is expected to address the issues associated with early age, while ensuring the long-term durability and performance of box-beam bridges.

Magnetoelastic Measurements of Steel Stress under Uniaxial Loading

2006 ◽  
Vol 321-323 ◽  
pp. 377-380 ◽  
Author(s):  
Hong C. Rhim ◽  
Bo Hwan Oh ◽  
Hyo Seon Park
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Uniaxial Loading ◽  
Magnetic Response ◽  
Reinforced Concrete Structures ◽  
Test Results ◽  
Traditional Technique ◽  
Steel Bar ◽  
Steel Bars ◽  
Different Diameters

An attempt has been made to measure existing steel stress using magnetoelasticity. A device has been developed and used for the measurement of magnetism in response to the deformation of a steel bar. The proposed technique can be used for the assessment of existing reinforced concrete structures by the measurements of steel stress embedded inside concrete. A traditional technique requires to break the existing steel bar to measure existing strain. However, the proposed technique is developed to measure the stress without damaging the steel bar. A successful application of magnetoelasticity depends on the establishment of relationship between elastic and magnetic response due to loading. To investigate the correlation between the two, steel bars are loaded in tension under uniaxial loading while the magnetic reading is recorded. Based on the test results, equations are suggested to predict stress for steel bars with different diameters.

Numerical Modeling of Continuously Reinforced Concrete Pavement Subjected to Environmental Loads

1998 ◽  
Vol 1629 (1) ◽  
pp. 76-89 ◽  
Author(s):  
Seong-Min Kim ◽  
Mooncheol Won ◽  
B. Frank McCullough
Keyword(s):  
Reinforced Concrete ◽  
Mechanistic Model ◽  
Primary Objective ◽  
Concrete Pavement ◽  
Thermal Coefficient ◽  
Bond Slip ◽  
Environmental Loads ◽  
Beneficial Effects ◽  
Design Variables ◽  
Steel Bar

Continuously reinforced concrete pavement (CRCP) performance depends on, among other factors, the characteristics of early developing cracks caused by environmental loads. The primary objective is to evaluate effects of design, materials, and construction variables on the characteristics of cracks in CRCP when subjected to environmental loads. A mechanistic model is developed using finite element formulations. Concrete and longitudinal steel are discretized using the plane strain and the frame elements, respectively. Various bond stress and slip models between concrete and longitudinal steel and between concrete and the underlying layers are developed using the spring elements. The creep effect is also included using the effective modulus method. CRCP responses from the model vary depending on the concrete and steel bond-slip models. An accurate bond-slip model needs to be investigated further by experiments to increase the accuracy of the mechanistic model. Concrete creep has beneficial effects on CRCP responses. The thermal coefficient of concrete has significant effects on CRCP responses. Using concrete with a low thermal coefficient will improve CRCP performance. Longitudinal steel variables—the amount of steel, bar diameter, and steel location—are important design variables that influence CRCP behavior. For given environmental conditions, an optimum steel design can be developed using the model developed.

scholarly journals Experimental Study of Replacement the Tension Reinforcing Bars in Concrete Beams by Steel Pipes

2018 ◽  
Vol 7 (4.20) ◽  
pp. 229
Author(s):  
Labeeb Saadoon Al-Yassri ◽  
Alaa Mahdi Al-Khekany ◽  
Hajer Satea Abbas
Keyword(s):  
Reinforced Concrete ◽  
Construction Projects ◽  
Concrete Beams ◽  
Small Diameter ◽  
Reinforced Concrete Beams ◽  
Steel Pipe ◽  
Steel Pipes ◽  
Steel Bar ◽  
Steel Bars ◽  
The Difference

Structures designed with reinforced concrete beams are used extensively in construction projects because of their functional and economic features. In this research, tested concrete beams were cast and reinforced with small diameter steel pipes and /or steel bars as flexural reinforcement to study the effect of this configuration of reinforcement on the structural behavior of reinforced concrete beams. The idea of this research involves performing and testing of four reinforced concrete beams reinforced by small diameter steel pipes with different percentages of replacement with traditional steel bars (0%, 33%, 66% and 100%). The experimental results showed that using of steel pipes reduces the flexural capacity by (2.7, 18.3, 37.5%) if compared with traditional steel bar according to the replacement percentages of (33%, 66%, and 100%) respectively. Moreover, the stiffness of beams reinforced with steel pipes (fully or partially) decreased as a result of the difference in the mechanical properties between steel bar and the steel pipe and also, the bond strength reduction between the smooth steel pipe and surrounded concrete.  

scholarly journals ULTRASONIC PULSE VELOCITY TEST OF REINFORCED CONCRETE WITH INDUCED CORROSION

2017 ◽  
Vol 7 (2) ◽  
pp. 9-17 ◽  
Author(s):  
Jason Maximino Co Ongpeng
Keyword(s):  
Reinforced Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Reinforcing Bars ◽  
Accelerated Corrosion ◽  
Steel Bar ◽  
Significant Damage ◽  
Steel Bars ◽  
Reinforced Steel

Non-destructive test has been applied to measure damage in structures. Common structures are assessed with the use of practical and easy application of ultrasonic pulse velocity (UPV). In this paper, the damage brought by corrosion was investigated using Proceq Punditlab having 54 kHz transducers oriented in direct transmission under the UPV. Fifty-four reinforced concrete of size 150 mm x 250 mm x 300 mm with two 10mm diameter reinforcing bars (Grade 40) and one 6mm diameter stainless steel bar (Type 304) was cast and tested. It had varying water cement ratio of 45%, 50%, and 55%with two conditions at day 0 (after curing), day 14, and day 28: non-accelerated condition under air-drying and accelerated condition using impressed current technique (ICT). The UPV test was conducted in each layer where reinforced steel bars were present and absent. It was found out that UPV test results was insignificant to all non-accelerated concrete, while it indicated significant damage for accelerated corrosion rate of more than 8 mm per year. In accelerated condition, the decrease in strength under UPV test was more than 20% for all specimens along the reinforced bars, and less than 15% for all specimens along the layer with no steel bars. This showed that the effect of corrosion greatly affects the entirety of structures near and far from the placement of reinforcing steel bars.

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