Fracture Surface Measurement of Concrete with Respect to Loading Speed

2014 ◽  
Vol 982 ◽  
pp. 94-99 ◽  
Author(s):  
Michal Mára ◽  
Petr Maca
Keyword(s):  
Fracture Surface ◽  
Reverse Engineering ◽  
Impact Loading ◽  
High Performance ◽  
High Performance Concrete ◽  
Laser Scanner ◽  
Plain Concrete ◽  
3D Models ◽  
Measured Data ◽  
Surface Measurement

Reverse engineering is a specialization which was developed a lot in the 21st century. The major aim is researching and describing the principals and procedures of process and structures. Reverse engineering in civil engineering is used to describe the applied loadings which caused corruption or failure of a structure or it is used to reconstruct 3D models of the original object. The aim of this paper is to compare response to static and impact loading of two materials, i.e. plain concrete and high-performance concrete (HPC), with respect to the fracture surface area. These areas were scanned by the 3D laser scanner and they were evaluated in the graphic programs. The main objective of this paper is a presentation of measured data, which can be used to determine the size of the applied loadings using reverse engineering.

scholarly journals Variation of the Pore Morphology during the Early Age in Plain and Fiber-Reinforced High-Performance Concrete under Moisture-Saturated Curing

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 975 ◽  
Author(s):  
Miguel Vicente ◽  
Jesús Mínguez ◽  
Dorys González
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Plain Concrete ◽  
Early Age ◽  
Geometrical Parameters ◽  
Pore Morphology ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
The One

In this paper, two concrete mixtures of plain concrete (PC) and steel fiber-reinforced high-performance concrete (SFRC) have been scanned in order to analyze the variation of the pore morphology during the first curing week. Six cylinders of 45.2-mm diameter 50-mm height were performed. All of the specimens were kept in a curing room at 20 °C and 100% humidity. A computed tomography (CT) scan was used to observe the internal voids of the mixtures, and the data were analyzed using digital image processing (DIP) software, which identified and isolated each individual void in addition to extracting all of their geometrical parameters. The results revealed that the SFRC specimens showed a greater porosity than the PC ones. Moreover, the porosity increased over time in the case of SFRC, while it remained almost constant in the case of PC. The porosity increased with the depth in all cases, and the lowest porosity was observed in the upper layer of the specimens, which is the one that was in contact with the air. The analysis of the results showed that the fibers provided additional stiffness to the cement paste, which was especially noticeable during this first curing week, resulting in an increasing of the volume of the voids and the pore size, as well as a reduction in the shape factor of the voids, among other effects.

Behaviour of Different Types of Concrete under Impact and Quasi-Static Loading

2013 ◽  
Vol 486 ◽  
pp. 295-300 ◽  
Author(s):  
Petr Máca ◽  
Petr Konvalinka ◽  
Manfred Curbach
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Impact Loading ◽  
High Performance ◽  
High Performance Concrete ◽  
Fibre Reinforced Concrete ◽  
Static Conditions ◽  
Direct Tensile ◽  
Direct Tensile Strength ◽  
The Impact

This paper describes mixture formulation of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) with 2% of fibres by volume and its response to quasi-static and dynamic impact loading. The UHPFRC mixture was prepared using locally available constituents and no special curing or mixing methods were used for its production. In addition, the mechanical parameters of three other types of concrete, i.e. normal strength concrete (NSC), fibre reinforced concrete (FRC) and high performance concrete (HPC) is compared. The main properties assessed throughout the experimental work are compressive, flexural and direct tensile strength as well as response of tested concretes to impact flexural loading. The impact loading is produced by a vertically falling weight of 24 kg from the height of 1 m on concrete prisms. The strain rate increase corresponds to low-velocity impacts such as vehicle crash or falling rocks. Compressive strength of UHPFRC exceeded 130 MPa and its direct tensile strength was 10.3 MPa. This type of concrete also exhibited strain hardening both in flexure under quasi-static conditions and during impact. Based on the comparison of impact reactions, it was concluded that the resistance of UHPFRC to impact loading is superior compared to the referent types of concretes (NSC, FRC, HPC).

Geometric Analysis of Pipeline Elbows Through Reverse Engineering and Their Associated Imperfections

2014 ◽  
Author(s):  
Muntaseer Kainat ◽  
Celal Cakiroglu ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Michael Martens
Keyword(s):  
Reverse Engineering ◽  
Wall Thickness ◽  
Geometric Analysis ◽  
Laser Scanner ◽  
Initial Imperfection ◽  
3D Models ◽  
Element Analysis ◽  
Engineering Software ◽  
Pipe Elbow ◽  
The Ideal

Pipe elbow is a common feature in pipelines and piping systems as a means to changing directions of otherwise straight pipelines. Irrespective of the processes involved in manufacturing pipe elbows, it is of interest to investigate whether they have any geometric imperfections. Researchers at the University of Alberta have devised a technique to measure initial imperfection of straight pipes prior to testing, using high resolution 3D surface profiler in conjunction with 3D reverse engineering software. The objective of the current study is to extend the imperfections measurement technique from measuring straight pipe segments to pipe elbows. Six (6) ninety (90) degree elbows are measured in this research with outside diameters ranging from NPS 12 inch to NPS 42 inch. A 3D laser scanner is used to acquire surface data and create 3D models corresponding to each elbow. A method for the geometric analysis of the elbows is developed using 3D inspection and reverse engineering software Geomagic®. The geometric idealization of a pipe elbow is a torus, which can be defined by a circle revolving around an axis, coplanar with the circle. The idealized geometry for each elbow is obtained through the developed method of geometric analysis, which includes the diameter of the circle defining the torus, and its distance from the axis of revolution. The difference between the ideal torus and the scanned geometry is considered as imperfection of each pipe elbow. The wall thickness values at the ends or edges of select pipe elbows are also measured from the scanned data and are reported as percentage deviation from the specified wall thickness around the perimeter at different cross sections. The 3D reverse engineering of the elbows indicated that they resemble the ideal geometry very closely. The ovalization imperfections are seen to be well within the value specified by CSA Z662-11. The wall thickness deviations are seen to vary between −10% to +25% of the specified value, with increased thickness being more prominent in the elbows. Finite element analysis of an elbow with thickness imperfection shows that higher hoop stress appears on the intrados than initially intended.

scholarly journals Synergetic Effect of Sugarcane Bagasse Ash with Low Modulus of Fiber Reinforced Concrete

2019 ◽  
Vol 8 (3) ◽  
pp. 7171-7175
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Research Work ◽  
Synergetic Effect ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Low Modulus ◽  
Sugar Cane Bagasse Ash

This research work has experimentally investigated on the effects of low modulus fibers (PP) used in concrete for the various percentages like 0. 0.5% and 1.0% (by volume fraction) along with different percentage of sugar cane bagasse ash from 0 to 15% replaced in Portland cement (by weight of binding material) for different mixes and tested for the various properties of high-performance concrete (HPC). This experimental test results indicated that the usage of SCBA is restricted up to 10% with 0.5% of PP (Polypropylene) along with 1.5% of superplasticizers produces the higher flexural strength was increased up to 78.30% and compressive strength of concrete was increased up to 25.80% when compared to control (plain) concrete at 28 days. Finally, the usage of low modulus fibre reinforced concrete to act as a corrosion inhibitor agent during the chloride attack than compared to high modulus fibers and reduce the plastic shrinkage due to excellent flexibility in concrete and also increases the life span.

Experimental and Numerical Investigation of the Polyurea-Coated Ultra-High-Performance Concrete (UHPC) Column under Lateral Impact Loading

2021 ◽  
Author(s):  
Bin Gao ◽  
Jun Wu ◽  
Pengcheng Jia ◽  
Shutao Li ◽  
Qiushi Yan ◽  
...  
Keyword(s):  
Axial Force ◽  
Impact Loading ◽  
High Performance ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Impact Resistance ◽  
Fe Model ◽  
Strengthening Effect ◽  
Lateral Impact ◽  
Ultra High Performance Concrete

It was found that polyurea coating could improve the integrity and the corresponding durability of the structural components. However, the strengthening effect of polyurea coatings for structures built with emerging ultra-high-performance concrete (UHPC) is still unknown due to the lack of studies. Therefore, this paper investigated the effect of the polyurea coating on the lateral impact resistance of UHPC columns through a combined numerical and experimental study. A total of five specimens were fabricated, including two UHPC columns and three UHPC columns with polyurea coating. To better characterize the structural response under dynamic loading, impact cases with different drop weight impact heights and axial force ratios were employed. The results showed that the UHPC column with polyurea coating exhibited superior lateral impact resistance compared to the UHPC column. The presence of the axial force increased the lateral impact stiffness and further reduced the deflection of the specimen. In contrast, the polyurea coating improved the specimen’s ductility and mitigated the peak impact force, thereby maintaining the specimen’s integrity without sudden shear failure. A three-dimensional finite element (FE) model of polyurea-coated UHPC columns under impact loading was then established and confirmed the experimental results. With the validated FE model, an intensive parametric study was conducted to investigate the effects of polyurea thickness, axial force ratio and impact energy on the lateral impact resistance of the UHPC column. The presence of the polyurea coating could significantly improve the lateral impact resistance of the specimen, thereby preventing the shear failure of the UHPC column, and thus, the effective thickness of the polyurea layer for the UHPC column was determined to be 2–6[Formula: see text]mm. The outcome of this research demonstrates the great merits of polyurea coating in improving the ductility and integrity of the UHPC column under lateral impact loading.

scholarly journals RESPONSE OF HIGH-PERFORMANCE FIBRE REINFORCED CONCRETE REINFORCED BY TEXTILE REINFORCEMENT TO IMPACT LOADING

2016 ◽  
Vol 56 (4) ◽  
pp. 328-335 ◽  
Author(s):  
Filip Vogel ◽  
Ondřej Holčapek ◽  
Petr Konvalinka
Keyword(s):  
Impact Loading ◽  
High Performance ◽  
High Performance Concrete ◽  
Impact Force ◽  
Cement Composites ◽  
Fibre Reinforced Concrete ◽  
Impact Machine ◽  
Three Point Bending ◽  
The Impact ◽  
High Performance Fibre

Generally, cement composites like high-performance concrete (HPC) are very brittle. The resistance to the impact loading of the HPFRC and the HPFRC reinforced by the textile reinforcement are compared in this article. The samples (0.56 × 0.1 × 0.1 m) were experimentally tested in three-point bending, by using horizontal impact machine. The better resistance of the textile reinforced HPFRC is obvious from the collected data (impact force, acceleration of hammer and acceleration of the tested sample).

scholarly journals A RE Methodology to achieve Accurate Polygon Models and NURBS Surfaces by Applying Different Data Processing Techniques

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1508
Author(s):  
Alejandro Pascual ◽  
Naiara Ortega ◽  
Soraya Plaza ◽  
Ibon Holgado ◽  
Jon Iñaki Arrizubieta
Keyword(s):  
Data Processing ◽  
Reverse Engineering ◽  
Data Acquisition ◽  
Laser Scanner ◽  
Point Clouds ◽  
3D Models ◽  
Machining Processes ◽  
Cross Sectional ◽  
Processing Step ◽  
Processing Techniques

The scope of this work is to present a reverse engineering (RE) methodology to achieve accurate polygon models for 3D printing or additive manufacturing (AM) applications, as well as NURBS (Non-Uniform Rational B-Splines) surfaces for advanced machining processes. The accuracy of the 3D models generated by this RE process depends on the data acquisition system, the scanning conditions and the data processing techniques. To carry out this study, workpieces of different material and geometry were selected, using X-ray computed tomography (XRCT) and a Laser Scanner (LS) as data acquisition systems for scanning purposes. Once this is done, this work focuses on the data processing step in order to assess the accuracy of applying different processing techniques. Special attention is given to the XRCT data processing step. For that reason, the models generated from the LS point clouds processing step were utilized as a reference to perform the deviation analysis. Nonetheless, the proposed methodology could be applied for both data inputs: 2D cross-sectional images and point clouds. Finally, the target outputs of this data processing chain were evaluated due to their own reverse engineering applications, highlighting the promising future of the proposed methodology.

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