scholarly journals Improving the Mechanical Performance of Shell Precast Concrete Blocks for Coastal Protection Structures of Hydraulic Works

2021 ◽  
Vol 11 (1) ◽  
pp. 6787-6791
Author(s):  
N. Viet Duc
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
High Performance ◽  
Mechanical Performance ◽  
Precast Concrete ◽  
Reference Beam ◽  
Concrete Cover ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Coastal Protection

Although the use of concrete and reinforced concrete for construction has been widespread, more studies are needed on marine structures exposed directly to corrosive environments to prolong their service life. This paper proposes a new type of shell precast concrete block for coastal structures, studying a beam consisting of 15mm High-Performance Glass Fiber-Reinforced Concrete (HPGFRC) at the bottom and 45mm Traditional Concrete (TC) for the rest of the structure. Steel bar reinforcements were placed at the bottom with a concrete cover of 25mm to avoid abrupt failure. The strength classes of HPGFRC and TC were 60MPa and 30MPa respectively. A reference beam consisting of TC only was also prepared for comparison. The four-point flexural bending test results showed that the first cracking strength of the proposed beam was 20% higher, as HPGFRC performed better on tension than TC. Additionally, HPGFRC's maximum strength was 25% greater than TC's. Furthermore, HPGFRC possessed more durable characteristics such as waterproof grade, abrasion resistance, and shrinkage than TC, promising to protect the reinforcement from the aggressive marine environment and corrosion, prolonging the service life of the structure.

scholarly journals Experimental and Numerical Investigation on Shear Retrofitting of RC Beams by Prefabricated UHPFRC Sheets

2016 ◽  
Vol 2 (5) ◽  
pp. 168-179
Author(s):  
Kian Aghani ◽  
Hassan Afshin
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Fem Analysis ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Externally Bonded ◽  
High Performance Fiber ◽  
Bending Capacity

Different methods are used for retrofitting RC members. One of the new methods in this field is using externally bonded fiber-reinforced Concrete (FRC) sheets in order to increase RC member’s shear and flexural strength. In this study, applicability of ultra-high performance fiber-reinforced concrete sheets in shear and flexural retrofitting of RC beams was investigated. In total, eight RC beams (dimensions 10×20×150 cm) with two different bending capacity and lack of shear strength were used and were tested in 3-points bending test. Of these, four were control beams and four were retrofitted with laterally bonded UHPFRC sheets. Dimensions of the sheets used for retrofitting were (3×15×126 cm). Also FEM analysis was used to model the effect of The method. the results show that this method can be well used for retrofitting RC beams. In this method the way of connecting sheets to beam’s surfaces has a fundamental role in behavior of retrofitted beams.

scholarly journals TENSILE BEHAVIOUR OF ULTRA-HIGH-PERFORMANCE STEEL FIBER REINFORCED CONCRETE

2020 ◽  
Author(s):  
Yuechen Yang ◽  
Mohammed Ismail ◽  
Stavroula Pantazopoulou ◽  
Dan Palermo
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Tensile Behaviour ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Splitting Test ◽  
High Performance Steel

Recent developments in the area of Ultra-High-Performance Steel Fiber Reinforced Concrete (UHP-SFRC) enables reduction in steel reinforcement, and has led to enhanced ductility and toughness of structural components owing to its resilient tensile behaviour. This paper presents the results of an experimental study conducted to investigate the tensile behaviour of UHP-SFRC. Four commercial mixes and two in-house mixes were evaluated using the procedures prescribed in the 2018 edition of Annex 8.1 of CSA-S6. Tensile strength of UHP-SFRC was quantified and correlated through the direct tension test, splitting test, inverse analysis of four-point bending test using either code expressions or nonlinear finite element analysis, and a calibrated empirical expression that links this property to the cylinder compressive strength. In addition, the effect of important parameters on flexural strength including casting methodology, volumetric ratio of steel fibers, and aspect ratio (shear span to depth ratio) of bending prisms have been assessed.

APPLICATION OF INNOVATIVE MATERIALS IN PRECAST CONCRETE STRUCTURES

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Klaus Holschemacher
Keyword(s):  
Reinforced Concrete ◽  
Construction Industry ◽  
Precast Concrete ◽  
Cementitious Materials ◽  
Concrete Cover ◽  
Fiber Reinforced Concrete ◽  
Textile Reinforced Concrete ◽  
Construction Methods ◽  
Corrosion Risk ◽  
Innovative Materials

Construction industry contributes essentially to Germany’s gross domestic product (GDP). In 2015 construction investments amounted around 300 billion Euro corresponding to a share of 10% of total GDP. Because of the essential importance of construction industry there are many activities aiming on reduction of construction costs and improvement of durability and sustainability. Recent tendencies in precast concrete industry include application of innovative materials like self-compacting concrete, fiber reinforced concrete, textile reinforced concrete, carbon concrete composite and strain hardening cementitious materials. The report describes the material developments and first applications for precast concrete members. By the application of non-metallic reinforcement, such as carbon meshes and carbon bars, there is no corrosion risk for the reinforcement resulting in an essentially lower concrete cover and depth of structural members. However, the use of carbon reinforcement requires new design concepts and new construction methods. By solving these problems there is a big chance for precast concrete industry to enhance their market share.

scholarly journals Precast Ultra-High-Performance Fiber-Reinforced Concrete (UHP-FRC) for Fast and Sustainable Pavement Repair

2019 ◽  
Vol 271 ◽  
pp. 01004
Author(s):  
Ashish Karmacharya ◽  
Shih-Ho Chao
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Transportation Infrastructure ◽  
Fiber Reinforced ◽  
Dense Microstructure ◽  
Concrete Production ◽  
High Performance Fiber ◽  
Maintenance Work

This paper presents a new methodology, which enables streets, roads, highways, bridges, and airfields to use an advanced fiber-reinforced concrete material, which can delay or prevent the deterioration of these transportation infrastructure when subjected to traffic and environmental loadings. The major problem of concrete is its considerable deterioration and limited service life due to its brittleness and limited durability. As a result, it requires frequent repair and eventual replacement, which consumes more natural resources. Ultra-high-performance fiber-reinforced concrete (UHP-FRC) introduces significant enhancement in the sustainability of concrete structures due to its dense microstructure and damage-tolerance characteristics. These characteristics can significantly reduce the amount of repair, rehabilitation, and maintenance work, thereby giving the transportation infrastructure a longer service life. This research addresses the strong need to develop fast and sustainable UHP-FRC materials for pavement repair that can be easily cast onsite without special treatments. This avoids any major changes to current concrete production practice and accelerates the use of UHP-FRC materials. This research investigated a new method for concrete repair by combining precast UHP-FRC panels with a small quantity of cast-in-place UHP-FRC for pavement repair without any dowel bars.

Relationship between Fiber Orientation and Flexural Strength in Ultra-High-Performance Fiber-Reinforced Concrete Panels

2014 ◽  
Vol 629-630 ◽  
pp. 71-78 ◽  
Author(s):  
Bo Zhou ◽  
Yuichi Uchida
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Fiber Orientation ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Concrete Panels ◽  
High Performance Fiber

In this study, the influence of fiber orientation on the flexural strength of ultra-high-performance fiber-reinforced concrete (UHPFRC) was examined. To this end, a circular UHPFRC panel measuring φ1,200 × 50 mm was cast from its center, and test specimens measuring 50 × 50 × 200 mm with 10 mm notches for three-point bending tests were cut from it with angles of 0, 30, 60 and 90° between the specimen axis and the radial direction of the panel. After the bending test, fiber orientation on the ruptured surfaces of the specimens was observed. The flexural strengths of the specimens cut at angles of 60, 30 and 0° were 80, 40 and 10% of that for the specimen cut at an angle of 90°. It was also found that the flexural strength of specimens cut from a rectangular panel cast from its center point depended on their original positions and orientation within the panel. Similar fiber orientation characteristics were found in the circular and rectangular panels.

scholarly journals Simulating Fiber-Reinforced Concrete Mechanical Performance Using CT-Based Fiber Orientation Data

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 717 ◽  
Author(s):  
Vladimir Buljak ◽  
Tyler Oesch ◽  
Giovanni Bruno
Keyword(s):  
Reinforced Concrete ◽  
Fiber Orientation ◽  
Control Experiment ◽  
Mechanical Performance ◽  
Damage Model ◽  
Fiber Reinforced Concrete ◽  
Material Behavior ◽  
Bending Test ◽  
Structural Level ◽  
Fiber Reinforced

The main hindrance to realistic models of fiber-reinforced concrete (FRC) is the local materials property variation, which does not yet reliably allow simulations at the structural level. The idea presented in this paper makes use of an existing constitutive model, but resolves the problem of localized material variation through X-ray computed tomography (CT)-based pre-processing. First, a three-point bending test of a notched beam is considered, where pre-test fiber orientations are measured using CT. A numerical model is then built with the zone subjected to progressive damage, modeled using an orthotropic damage model. To each of the finite elements within this zone, a local coordinate system is assigned, with its longitudinal direction defined by local fiber orientations. Second, the parameters of the constitutive damage model are determined through inverse analysis using load-displacement data obtained from the test. These parameters are considered to clearly explain the material behavior for any arbitrary external action and fiber orientation, for the same geometrical properties and volumetric ratio of fibers. Third, the effectiveness of the resulting model is demonstrated using a second, “control” experiment. The results of the “control” experiment analyzed in this research compare well with the model results. The ultimate strength was predicted with an error of about 6%, while the work-of-load was predicted within 4%. It demonstrates the potential of this method for accurately predicting the mechanical performance of FRC components.

Study of Ultra High Performance Fiber Reinforced Concrete with Expansive and Shrinkage Reducing Agents

2014 ◽  
Vol 980 ◽  
pp. 137-141 ◽  
Author(s):  
Alessandro Nardinocchi ◽  
Valeria Corinaldesi
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Mechanical Performance ◽  
Drying Shrinkage ◽  
Reducing Agents ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Binder Ratio ◽  
High Performance Fiber ◽  
Suitable Combination

UltraHigh Performance Fiber Reinforced Concrete (UHPFRC) exhibits remarkable mechanical performance, which can allow to reduce the cross-section of structural members. However,a problem involving UHPFRC isthe likely tendency to crack at early age, due to autogenous and plastic shrinkages, caused by the very low water-to-binder ratio adopted. Therefore, this experimental work intends to detect the effectiveness of a possible solution for reducing the risk of shrinkage cracks in UHPFRC, by adding to the mixture a suitable combination of expansive and shrinkage reducing agents.Compressionand bending testswere carried out up to28 days of curing. Free drying shrinkage strains were evaluated up to 56 days of exposure to 50% relative humidity. The experimental results obtained by using expansive and shrinkage reducing agents were extremely encouraging in termsof free dryingshrinkage reduction, and even surprising in terms of flexural behaviour.

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