Temperature Effect on the Mechanical Properties of Very High Performance Concrete

2018 ◽  
Vol 34 ◽  
pp. 29-39
Author(s):  
Mebarek Belaoura ◽  
Dalila Chiheb ◽  
Mohamed Nadjib Oudjit ◽  
Abderrahim Bali
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Exothermic Reaction ◽  
Physical And Mechanical Properties ◽  
Mass Effect ◽  
Mechanical Tests ◽  
Conventional Concrete ◽  
Very High

This study aims at a better understanding of the behaviour of very high performance concretes (VHPC) subjected to high temperatures. The temperature increase within the concrete originating from the hydratation exothermic reaction of cement is emphasized by the mass effect of the structures and can lead to thermal variations of around 50°C between the heart and the structures walls. These thermal considerations are not without consequence on durability and the physical and mechanical properties of very high performance concrete, such as the compressive strength. This work is an experimental research that shows the effects of temperature on the mechanical properties of very high performance concrete (VHPC) and compares them with those of conventional concrete and HPC. Test specimens in usual concrete, HPC and VHPC are made, preserved till maturity of the concrete, and then subjected to a heating-cooling cycle from room temperature to 500°C at heating rate 0.1°C/min. Mechanical tests on the hot concrete and cooling (air and water) were realized. The results show that the mechanical characteristics of VHPC (density, compressive strength, tensile strength and elastic modulus) decrease with increasing temperature, but their strength remains higher than that of conventional concrete.

scholarly journals State of the Art: Mechanical Properties of Ultra-High Performance Concrete

2017 ◽  
Vol 3 (3) ◽  
pp. 190-198 ◽  
Author(s):  
Mohamadtaqi Baqersad ◽  
Ehsan Amir Sayyafi ◽  
Hamid Mortazavi Bak
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
State Of The Art ◽  
High Strength ◽  
Structural Members ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Past ◽  
Very High

During the past decades, there has been an extensive attention in using Ultra-High Performance Concrete (UHPC) in the buildings and infrastructures construction. Due to that, defining comprehensive mechanical properties of UHPC required to design structural members is worthwhile. The main difference of UHPC with the conventional concrete is the very high strength of UHPC, resulting designing elements with less weight and smaller sizes.  However, there have been no globally accepted UHPC properties to be implemented in the designing process. Therefore, in the current study, the UHPC mechanical properties such as compressive and tensile strength, modulus of elasticity and development length for designing purposes are provided based on the reviewed literature. According to that, the best-recommended properties of UHPC that can be used in designing of UHPC members are summarized. Finally, different topics for future works and researches on UHPC’s mechanical properties are suggested.

scholarly journals Comparative Study of High-Performance Concrete Characteristics and Loading Test of Pretensioned Experimental Beams

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 427
Author(s):  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Load Capacity ◽  
Materials Testing ◽  
Loading Test ◽  
Conventional Concrete ◽  
Concrete Mechanical Properties ◽  
Normal Strength

High-performance concrete (HPC) is subjected to wide attention in current research. Many research tasks are focused on laboratory testing of concrete mechanical properties with specific raw materials, where a mixture is prepared in a relatively small amount in ideal conditions. The wider utilization of HPC is connected, among other things, with its utilization in the construction industry. The paper presents two variants of HPC which were developed by modification of ordinary concrete used by a precast company for pretensioned bridge beams. The presented variants were produced in industrial conditions using common raw materials. Testing and comparison of basic mechanical properties are complemented with specialized tests of the resistance to chloride penetration. Tentative expenses for normal strength concrete (NSC) and HPC are compared. The research program was accomplished with a loading test of model experimental pretensioned beams with a length of 7 m made of ordinarily used concrete and one variant of HPC. The aim of the loading test was to determine the load–deformation diagrams and verify the design code load capacity calculation method. Overall, the article summarizes the possible benefits of using HPC compared to conventional concrete.

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

Physical and Mechanical Properties of High Performance Concrete with Alum Sludge as Partial Cement Replacement

2013 ◽  
Vol 65 (2) ◽  
Author(s):  
Haider Mohammed Owaid ◽  
Roszilah Hamid ◽  
Siti Rozaimah Sheikh Abdullah ◽  
Noorhisham Tan Kofli ◽  
Mohd Raihan Taha
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Physical And Mechanical Properties ◽  
Cement Replacement ◽  
Alum Sludge ◽  
Partial Cement Replacement

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 Meta-Analysis of Fiber Impact on Mechanical Properties of Ultra-High Performance Concrete

2020 ◽  
Author(s):  
Faiq M. Al-Zwainy ◽  
Hussam k. Risan ◽  
Rana I. K. Zaki
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Meta Analysis ◽  
High Strength ◽  
Ultimate Compressive Strength ◽  
Ultra High Performance Concrete

The purpose of this study was to conduct a meta-analysis that shows the influence of fiber on ultimate compressive strength and tensile strength of ultra-high performance concrete. The internet scholarly search engines and ScienceDirect article references were used to illustrate the papers concerning the experimental investigations of mechanical properties of ultra-high strength concrete with and without fiber with clearly, completely and comparative raw data. The normal concrete test results were dismissed from this search. Seven trials were identified based on the adopted inclusion and exclusion criteria above. The meta-analysis based on standardized mean difference was carried out on the basis of a fixed-effects model for the major outcomes of the ultimate compressive and tensile properties of ultra-high performance concrete. A total of 888 test specimens were enrolled in these seven trials. The combined analysis yielded a sign of a significant improvement in ultimate compressive strength and tensile strength of ultra-high strength concrete with fiber addition of 2% by concrete volume. The summary effect size of ultimate compressive strength was 2.34 while a more improvement in term of tensile strength with effect size of 2.64. By addition fiber of 2% provides a significant benefit in mechanical properties of ultra-high performance concrete.

scholarly journals Mechanical Properties of Ultra-High Performance Concrete before and after Exposure to High Temperatures

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 770 ◽  
Author(s):  
How-Ji Chen ◽  
Yi-Lin Yu ◽  
Chao-Wei Tang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperatures ◽  
High Performance ◽  
High Performance Concrete ◽  
Silicon Powder ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Splitting Strength ◽  
Experimental Group

Compared with ordinary concrete, ultra-high performance concrete (UHPC) has excellent toughness and better impact resistance. Under high temperatures, the microstructure and mechanical properties of UHPC may seriously deteriorate. As such, we first explored the properties of UHPC with a designed 28-day compressive strength of 120 MPa or higher in the fresh mix phase, and measured its hardened mechanical properties at seven days. The test variables included: the type of cementing material and the mixing ratio (silica ash, ultra-fine silicon powder), the type of fiber (steel fiber, polypropylene fiber), and the fiber content (volume percentage). In addition to the UHPC of the experimental group, pure concrete was used as the control group in the experiment; no fiber or supplementary cementitious materials (silica ash, ultra-fine silicon powder) were added to enable comparison and discussion and analysis. Then, the UHPC-1 specimens of the experimental group were selected for further compressive, flexural, and splitting strength tests and SEM observations after exposure to different target temperatures in an electric furnace. The test results show that at room temperature, the 56-day compressive strength of the UHPC-1 mix was 155.8 MPa, which is higher than the >150 MPa general compressive strength requirement for ultra-high-performance concrete. The residual compressive strength, flexural strength, and splitting strength of the UHPC-1 specimen after exposure to 300, 400, and 500 °C did not decrease significantly, and even increased due to the drying effect of heating. However, when the temperature was 600 °C, spalling occurred, so the residual mechanical strength rapidly declined. SEM observations confirmed that polypropylene fibers melted at high temperatures, thereby forming other channels that helped to reduce the internal vapor pressure of the UHPC and maintain a certain residual strength.

An Experimental Study on Evaluation of Mechanical Properties in High Performance Concrete Using Admixture

2013 ◽  
Vol 372 ◽  
pp. 231-234
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Nam Yong Eom ◽  
Sun Woong Kim ◽  
Do Gyeum Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
High Performance ◽  
High Performance Concrete ◽  
Splitting Tensile Strength ◽  
Experimental Investigations ◽  
Binder Ratio

In this study, some experimental investigations on the development of mechanical properties with age of high performance concrete (HPC) incorporated with blast furnace slag with fly ash or silica fume have been reported. Four different blended HPC were prepared in 0.40 water-binder ratio. At every four mixtures, the compressive strength, splitting tensile strength and modulus of elasticity at 7 and 28 days have been observed for HPC developments. Consequently, only replacement of silica fume significantly increases the mechanical properties in terms of compressive strength, splitting tensile strength and modulus of elasticity.

The Effect of Mineral Admixtures on Mechanical Properties of High Performance Concrete at very Low Temperature

2014 ◽  
Vol 584-586 ◽  
pp. 1509-1513
Author(s):  
Nan Zhang ◽  
Juan Liao ◽  
Tao Zhang ◽  
Wen Zhan Ji ◽  
Bao Hua Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Low Temperature ◽  
High Performance ◽  
High Performance Concrete ◽  
Splitting Tensile Strength ◽  
Mineral Admixtures ◽  
The Difference ◽  
Very Low Temperature

The effect of very low temperature on high performance concrete (HPC) mechanical properties is studied by using a reasonable testing method. The results show that the compressive strengths of concrete are increasing with lower temperatures. Fly ash (FA), compared to ground granulated blast-furnace slag (GGBFS), is positive to the compressive strength increasing at low temperature. The splitting tensile strengths of concrete appear a maximum at-40°C~-80°C. The compound replacement by GGBFS and FA makes the splitting tensile strength present the extreme value at higher temperature. At very low temperature, the single or compound replacement by mineral admixtures can result in the difference of the relationship between compressive strength and splitting tensile strength, and the degradation of concrete subjected to cold-thermal shocks.

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