scholarly journals Mechanical Properties of High-Strength High-Performance Reinforced Concrete Shaft Lining Structures in Deep Freezing Wells

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Shilong Peng ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Xiaojian Wang ◽  
Mingjing Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Shear Failure ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Criterion ◽  
Hydraulic Pressure ◽  
Element Analysis ◽  
Deep Freezing ◽  
Shaft Lining

As coal resources must be mined from ever deeper seams, high-strength, high-performance concrete shaft linings are required to resist the load of the soil surrounding the deep freezing well. In order to determine the optimal concrete mix for the unique conditions experienced by such high-strength high-performance reinforced concrete shaft lining (HSHPRCSL) structures in deep freezing wells, an experimental evaluation of scaled HSHPRCSL models was conducted using hydraulic pressure load tests. It was observed that as the specimens ruptured, plastic bending of the circumferential reinforcement occurred along the failure surface, generated by compression-shear failure. These tests determined that HSHPRCSL capacity was most affected by the ultimate concrete uniaxial compressive strength and the thickness-diameter ratio and least affected by the reinforcement ratio. The experimental results were then used to derive fitting equations, which were compared with the results of theoretical expressions derived using the three-parameter strength criterion for the ultimate bearing capacity, stress, radius, and load in the elastic and plastic zones. The proposed theoretical equations yielded results within 8% of the experimentally fitted results. Finally, the finite element analysis method is used to verify the abovementioned results, and all errors are less than 12%, demonstrating reliability for use as a theoretical design basis for deep HSHPRCSL structures.

Accelerated testing of super lightweight UHPC waffle deck under heavy vehicle simulator

2021 ◽  
Vol 16 (2-3) ◽  
pp. 61-74
Author(s):  
Sahar Ghasemi ◽  
Amir Mirmiran ◽  
Yulin Xiao ◽  
Kevin Mackie
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
High Performance Concrete ◽  
High Strength ◽  
Heavy Vehicle ◽  
Wheel Load ◽  
Element Analysis ◽  
Vehicle Simulator ◽  
Pavement Testing ◽  
Heavy Vehicle Simulator

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

Repair of Severely Damaged Reinforced Concrete Beams with High-Strength Cementitious Grout

2020 ◽  
Vol 2674 (6) ◽  
pp. 372-384
Author(s):  
Antoine N. Gergess ◽  
Mahfoud Shaikh Al Shabab ◽  
Razane Massouh
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Rc Structures

High-strength cementitious materials such as high-performance concrete are extensively used for retrofit of reinforced concrete (RC) structures. The effectiveness of these materials is increased when mixed with steel fibers. A commonly used technique for strengthening and repair of RC beams consists of applying high-performance fiber-reinforced concrete jackets around the beam perimeter. This paper investigates the jacketing method for repairing severely damaged RC beams. Four 2 m (6 ft 63/4 in.) long rectangular RC beams, 200 × 300 mm (8 ×12 in.) were initially cast and loaded until failure based on three-point bending tests. The four beams were then repaired by thickening the sides of the damaged RC beams using a commercially available high-strength shrinkage grout with and without steel fibers. Strain and deformation were recorded in the damaged and repaired beams to compare structural performance. It is shown that the flexural strength of the repaired beams is increased and the crack pattern under loading is improved, proving that the proposed repair method can restore the resistance capacity of RC beams despite the degree of damage. A method for repair is proposed and an analytical investigation is also performed to understand the structural behavior of the repaired beams based on different thickening configurations.

scholarly journals Flexural and Shear Tests on Reinforced Concrete Bridge Deck Slab Segments with a Textile-Reinforced Concrete Strengthening Layer

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4210 ◽  
Author(s):  
Viviane Adam ◽  
Jan Bielak ◽  
Christian Dommes ◽  
Norbert Will ◽  
Josef Hegger
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Large Scale ◽  
Shear Failure ◽  
Bridge Deck ◽  
High Strength ◽  
Shear Capacity ◽  
Strengthening Effect ◽  
Textile Reinforced Concrete ◽  
Carbon Fibre Reinforced Polymer

Many older bridges feature capacity deficiencies. This is mainly due to changes in code provisions which came along with stricter design rules and increasing traffic, leading to higher loads on the structure. To address capacity deficiencies of bridges, refined structural analyses with more detailed design approaches can be applied. If bridge assessment does not provide sufficient capacity, strengthening can be a pertinent solution to extend the bridge’s service lifetime. For numerous cases, applying an extra layer of textile-reinforced concrete (TRC) can be a convenient method to achieve the required resistance. Here, carbon fibre-reinforced polymer reinforcement together with a high-performance mortar was used within the scope of developing a strengthening layer for bridge deck slabs, called SMART-DECK. Due to the high tensile strength of the carbon and its resistance to corrosion, a thin layer with high strength and low additional dead load can be realised. While the strengthening effect of TRC for slabs under flexural loading has already been investigated several times, the presented test programme also covered increase in shear capacity, which is the other crucial failure mode to be considered in design. A total of 14 large-scale tests on TRC-strengthened slab segments were tested under static and cyclic loading. The experimental study revealed high increases in capacity for both bending and shear failure.

Industrial Test on Outer Frozen Shaft Wall of High Strength and High Performance Concrete

2011 ◽  
Vol 179-180 ◽  
pp. 569-574
Author(s):  
Zhong Wen Yue ◽  
Hui Zhang ◽  
Bo Yang Dou
Keyword(s):  
Quality Control ◽  
Industrial Application ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Industrial Test ◽  
Construction Technology ◽  
Study Results ◽  
Shaft Lining ◽  
Shaft Wall

To study the industrial technology for application of the C100 High strength and high performance concrete which is in freezing shaft lining of thick overburden, the industrial test of the shaft wall of high strength and high performance concrete is carried out under the engineering background of auxiliary shaft in Yuncheng coal mine of Juye coal mining area in Shandong Province. The verified laboratory testing results comported with the results of industrial technology from macro-mechanics, failure fractal, resultant morphology and pore characteristics. And the quality control system of high performance concrete and construction technology can be established. The results show that the experimental formula and construction technology of C100 high strength and high performance concrete can meet the requirement of field concrete shaft lining and achieve the high level of quality control. The industrial application and study results accord with the field requirement. Furthermore, the study results also provide experimental basis and industrial production data for industrial application of C100 high strength and high performance concrete.

scholarly journals Flexural Behavior Performance of Reinforced Concrete Slabs Mixed with Nano- and Microsilica

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Rakesh Kancharla ◽  
Venkata Rao Maddumala ◽  
T. V. N. Prasanna ◽  
Lokaiah Pullagura ◽  
Ratna Raju Mukiri ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Flexural Behavior ◽  
Concrete Slabs ◽  
The Past ◽  
Reinforced Concrete Slabs ◽  
Concrete Mix ◽  
Bending Behavior

Present technology has been evaluated greatly over the past decades, where new particles are being designed and fabricated to fulfill specific needs. The field of nano- and micromaterials has prospered in many disciplines. It has been recently used in reinforced concrete in the production of high-strength, high-performance concrete. Microsilica (MS) and nanosilica (NS) particles have proven to be highly profitable to the concrete mix. Concrete has become denser with considerable improvement in their mechanical characteristics, particularly compressive strength. This proposed method includes a comparative study of the flexural bending behavior of conventional reinforced concrete (without MS or NS) slabs with other slabs. Each has various mixes of MS and NS particles incorporated into the concrete mix. The material content utilized in the slabs is kept constant by replacing a portion of the cement with an equivalent amount of either NS or MS particles or both. MS particles are altered from 0, 5, and 10% while NS particles are altered from 0, 0.5, and 1.0%. It cracks the widths and has higher final load-bearing capacity.

Preparation Experiment and Engineering Application of High Performance Concrete of Freezing Shaft in Deep Alluvium

2014 ◽  
Vol 584-586 ◽  
pp. 1407-1411
Author(s):  
Zhi Shu Yao ◽  
Zhen Xu ◽  
Hai Qing Song
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Engineering Application ◽  
High Strength ◽  
Engineering Practice ◽  
Mixture Ratio ◽  
Curing Conditions ◽  
Remarkable Effect ◽  
Shaft Lining

According to the special construction environment and curing conditions of the freezing shaft inner and outer shaft lining in deep alluvium, first,configuration principle of high strength high performance concrete of freezing shaft in deep alluvium is proposed; Then raw materials are selected according to the preparation approach, and preparation experimental study of high strength high performance concrete is conducted with C60, C65, C70and C75 , and the optimum mixture ratio is obtained, and applied to the engineering practice, achieving remarkable effect.

Bond Strength and Damage of Long Rebar Anchored in HPC under Static and Fatigue Loading

2006 ◽  
Vol 324-325 ◽  
pp. 867-870 ◽  
Author(s):  
Jian Zhuang Xiao ◽  
Chuan Zeng Zhang ◽  
Horst Falkner
Keyword(s):  
Static Loading ◽  
High Strength Steel ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fatigue Loading ◽  
Element Analysis ◽  
Bond Behaviour ◽  
Steel Bar ◽  
Reinforcement Bar

This paper presents an experimental study on the anchorage behaviour of long high-strength steel rebars embedded in high-performance concrete (HPC) under both static loading and fatigue loading. The HPC was designed as C60 with its cube compressive strength larger than 60 MPa, and the high-strength steel bar was adopted as HRB500 with its characteristic yield strength equals 500 MPa. Under 3×106 fatigue loading cycles and then followed by a monotonous static loading, the strain and the stress state of the reinforcement bar, and the bond stress between the concrete and the 700 mm-long bar were investigated. Based on the test results and the ANSYS finite element analysis, the bond behaviour between HPC and long high-strength steel bars is discussed.

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