High-temperature mechanical properties and microscopic analysis of hybrid-fibre-reinforced high-performance concrete

2013 ◽  
Vol 65 (3) ◽  
pp. 139-147 ◽  
Author(s):  
Lan Yan ◽  
YongMing Xing ◽  
JiJun Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Performance ◽  
High Performance Concrete ◽  
Microscopic Analysis ◽  
High Temperature Mechanical Properties ◽  
Hybrid Fibre

The Influence on High-Temperature Mechanical Properties of Hybrid-Fiber-Reinforced High-Performance Concrete and Microscopic Analysis

2012 ◽  
Vol 226-228 ◽  
pp. 1709-1713
Author(s):  
Lan Yan ◽  
Y.M. Xing ◽  
Ji Jun Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Transition Zone ◽  
High Performance ◽  
Room Temperature ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Interfacial Transition Zone ◽  
Hybrid Fiber ◽  
High Temperature Mechanical Properties

This paper investigated the high temperature mechanical properties of the hybrid fiber reinforced high performance concrete (HFHPC) and normal concrete (NC) .After being subjected to different elevated heating temperatures, two kinds of concretes have been tested for the compressive strength, splitting tensile strength and flexural strength of test specimen at room temperature and 200 °C,400 °C,600 °C,800 °C.Microstructure changes of concrete were also observed by using Scanning Electron Microscopy (SEM) after high temperature. The results show that the hybrid fiber can significantly increase mechanical properties of the concrete at room temperature and high temperature. SEM and XRD analysis shows that there is a permeable diffusion layer in the steel fiber surface because of solid state reaction in the Interfacial Transition Zone of steel fiber and concrete. This permeable diffusion layer is white, bright, serrated and mainly consist of FeSi2 and the complex hydrated calcium silicate. The compounds of this layer change the Interfacial Transition Zone structure, enhance bonding capacity of the steel fiber and matrix, and increase the high temperature mechanical properties of concrete.

Material Properties of Ultra - High Performance Concrete in Extreme Conditions

2016 ◽  
Vol 711 ◽  
pp. 157-162 ◽  
Author(s):  
David Citek ◽  
Milan Rydval ◽  
Stanislav Rehacek ◽  
Jiří Kolísko
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Material Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Accurate Information ◽  
Extreme Conditions ◽  
Ultra High Performance Concrete ◽  
Freeze Thaw

The Ultra High Performance Concrete (UHPC) is a very promising material suitable for application in special structures. However, the knowledge of performance of this relatively new material is rather limited. The exceptional mechanical properties of UHPC allow for a modification of the design rules, which are applicable in ordinary or high strength concrete. This paper deals in more detail with impact of thermal stress on bond properties between prestressing strands and UHPC and an influence of high temperature to final material properties of different UHPC mixtures. Specimens in the first experimental part were subjected to the cycling freeze-thaw testing. The relationship between bond behavior of both type of material (UHPC and ordinary concrete) and effect of cycling freeze-thaw tests was investigated. The second part of experimental work was focused on mechanical properties of UHPC exposure to the high temperature (Tmax = 200°C to Tmax = 1000°C). Tested mechanical properties were compressive and flexural strengths, the fracture properties will be presented in the next paper. The obtained experimental data serve as a basis for further systematic experimental verification and more accurate information about the significantly higher material properties of UHP(FR)C and its behavior in extreme conditions.

Contribution of Reinforcing Fiber Types on the Mechanical Properties of High Performance Concrete Subjected to High Temperature

2013 ◽  
Vol 368-370 ◽  
pp. 1052-1055
Author(s):  
Seung Jo Lee ◽  
Jung Min Park
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Weight Reduction ◽  
High Performance ◽  
High Performance Concrete ◽  
Reduction Ratio ◽  
Fiber Types ◽  
Residual Compressive Strength ◽  
Reinforcing Fiber

The aim of the study is to improve the understanding of the influence of reinforcing fiber types on the mechanical properties of high performance concretes (HPC) subjected to high temperature. The mechanical properties measured include residual compressive strength, weight reduction ratio, outward appearance property, and failure mode. Nylon, polypropylene, and steel fiber were added to enhance mechanical property of the concretes. After exposure to high temperatures ranged from 100 to 800°C, mechanical properties of fiber-toughened HPC were investigated. For HPC, although residual compressive strength was decreased by exposure to high temperature over 500°C, weight reduction ratio was significantly higher than that before heating temperature.

scholarly journals Mechanical Properties of High-Performance Hybrid Fibre-Reinforced Concrete at Elevated Temperatures

2021 ◽  
Vol 13 (23) ◽  
pp. 13392
Author(s):  
Moawiah Mubarak ◽  
Raizal Saifulnaaz Muhammad Rashid ◽  
Mugahed Amran ◽  
Roman Fediuk ◽  
Nikolai Vatin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Fibre Reinforced Concrete ◽  
Explosive Spalling ◽  
Hybrid Fibre ◽  
Before And After

Deterioration of concrete’s integrity under elevated temperature requires an alteration in its composition to have better thermal stability. Fibre-reinforced concrete has shown significant improvements in concrete strength and this paper aimed to investigate the influence of steel (ST) and polypropylene (PP) fibres on the behaviour of high-performance concrete (HPC) exposed to elevated temperatures. Six mixtures were prepared and cast by adding one or two types of polypropylene fibre (54 and 9 mm) at 0.25 or 0.5% and either singly or in a hybrid combination, along with a fixed volumetric content at 1% of five-dimensional hooked steel (5DH) fibres. At the age of 28 days, samples were heated to the targeted temperature of 800 °C and cooled down naturally to the laboratory temperature. Visual inspection, flexural, split tensile and compressive strengths were examined before and after the exposure to elevated temperatures. Results exhibited that the hybridization of long and short PP fibres, along with the ST fibres, has notably improved all residual mechanical properties of HPC and kept the integrity of concrete after exposure to elevated temperatures. In addition, PP fibres can significantly prevent spalling, but ST fibres were ineffective in mitigating explosive spalling in beams specimens.

TEM Studies of Grain Boundary Films in Si3N4 Ceramics

1991 ◽  
Vol 49 ◽  
pp. 930-931
Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Hot Isostatic Pressing ◽  
Amorphous Film ◽  
Liquid Phase Sintering ◽  
Second Phase ◽  
High Temperature Mechanical Properties ◽  
Triple Points ◽  
Boundary Films

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.

Mechanical properties and durability of high - performance concrete for bridge decks

PCI Journal ◽  
2008 ◽  
Vol 53 (4) ◽  
pp. 108-130
Author(s):  
Mohsen A. Issa ◽  
Atef A. Khalil ◽  
Shahidul Islam ◽  
Paul D. Krauss
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks
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