Physical and mechanical properties of sandstone containing a single fissure after exposure to high temperatures

2016 ◽  
Vol 26 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Tantan Zhu ◽  
Hongwen Jing ◽  
Haijian Su ◽  
Qian Yin ◽  
Mingrui Du ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperatures ◽  
Physical And Mechanical Properties

scholarly journals Effects of High Temperatures on the Physical and Mechanical Properties of Carbonated Ordinary Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Qifang Xie ◽  
Lipeng Zhang ◽  
Shenghua Yin ◽  
Baozhuang Zhang ◽  
Yaopeng Wu
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Elastic Modulus ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Time Service ◽  
Different Temperatures ◽  
Cooling Methods

Fires are always known for seriously deteriorating concrete in structures, especially for those with certain carbonation due to long-time service. In this paper, 75 prism specimens were prepared and divided into four groups (three carbonated groups and one uncarbonated group). Specimens were tested under different temperatures (20, 300, 400, 500, 600, and 700°C), exposure times (3, 4, and 6 hours), and cooling methods (water and natural cooling). Surface characteristics, weight loss rate, and residual mechanical properties (strength, initial elastic modulus, peak, and ultimate compressive strains) of carbonated concrete specimens after elevated temperatures were investigated and compared with that of the uncarbonated ones. Results show that the weight loss rates of the carbonated concrete specimens are slightly lower than that of the uncarbonated ones and that the cracks are increased with raising of temperatures. Surface colors of carbonated concrete are significantly changed, but they are not sensitive to cooling methods. Surface cracks can be evidently observed on carbonated specimens when temperature reaches 400°C. Residual compressive strength and initial elastic modulus of carbonated concrete after natural cooling are generally larger than those cooled by water. The peak and ultimate compressive strains of both carbonated and uncarbonated concrete specimens increase after heating, but the values of the latter are greater than that of the former. Finally, the constitutive equation to predict the compressive behaviors of carbonated concrete after high temperatures was established and validated by tests.

scholarly journals Influence of the absorbed dose of radiation radiation on the destruction of polypropylene, depending on the location of the sample to the electron radiator

2020 ◽  
Vol 64 (11) ◽  
pp. 135-142
Author(s):  
Elvina R. Rakhmatullina ◽  
◽  
Rezeda Yu. Galimzyanova ◽  
Maria S. Lisanevich ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ionizing Radiation ◽  
High Temperatures ◽  
Medical Devices ◽  
Absorbed Dose ◽  
Physical And Mechanical Properties ◽  
Special Place ◽  
The World ◽  
Object Of Study ◽  
Surgical Gowns

Currently, polypropylene is one of the most common polymers in the world. Due to its resistance to high temperatures, strength and density, it has found very wide application in the field of medicine. Polypropylene produces medical devices, pharmaceutical packaging, containers, suture threads. But a special place is occupied by non-woven materials based on polypropylene: surgical underwear, surgical gowns. As you know, to sterilize these products using ionizing radiation, which is the most effective of all methods. However, it leads to the destruction of polypropylene, as a result of which its physical and mechanical properties deteriorate. It is also known that the dose of radiation can vary depending on the location of the product in the box. Thus, materials can be degraded to varying degrees depending on the location in the box from the electronic emitter. As the object of study was selected: PP 1562R polypropylene produced by OAO Nizhnekamskneftekhim. It has been established that the location of polypropylene samples upon irradiation has little effect on the degree of their destruction.

Changes in physical and mechanical properties of limestone and marble after exposure to different high temperatures

2019 ◽  
Vol 53 (3) ◽  
pp. 378-385
Author(s):  
Weiqiang Zhang ◽  
Chenchen Xu ◽  
Jishi Geng
Keyword(s):  
Mechanical Properties ◽  
Thermal Diffusivity ◽  
High Temperatures ◽  
Mechanical Characteristics ◽  
Heating Temperature ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
High Temperature Treatment ◽  
Peak Strain ◽  
Physical And Mechanical Characteristics

Under or after high-temperature treatment, the physical and mechanical characteristics of limestone and marble change significantly. This study seeks to understand the effect of high temperatures on physical and mechanical properties (such as density, porosity, permeability, P-wave velocity, thermal diffusivity, elastic modulus, uniaxial compressive strength, peak strain and Poisson's ratio) of limestone and marble. The results indicate that, from room temperature to 300°C, most of the physical and mechanical indices of limestone and marble change relatively little, except for thermal diffusivity. Above 300°C (especially at 400–600°C), physical and mechanical characteristics change significantly, corresponding to the changes to minerals between 400 and 600°C. These results confirm the important link between physical and mechanical properties and heating temperature, and can provide the basis of theory and reference for related engineering.

Physical and mechanical properties of C60under high pressures and high temperatures

2006 ◽  
Vol 26 (3) ◽  
pp. 175-183 ◽  
Author(s):  
W. Qiu ◽  
S. Chowdhury ◽  
R. Hammer ◽  
N. Velisavljevic ◽  
P. Baker ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperatures ◽  
High Pressures ◽  
Physical And Mechanical Properties

scholarly journals Physical and Mechanical Properties of Clay After Heating in Different Oxygen Levels and Cooling With Different Methods

2021 ◽  
Author(s):  
Zhihao Dong ◽  
Qiang Sun ◽  
Weiqiang Zhang
Keyword(s):  
Mechanical Properties ◽  
High Temperatures ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Surface Color ◽  
Anoxic Conditions ◽  
Oxygen Levels ◽  
The Core ◽  
Reduction Of Iron ◽  
Strength And Deformation

Abstract Clay is a vital industrial raw material, and its physical and mechanical properties undergo significant changes when heated at high temperatures. A good understanding of those properties can provide details on the best use of clay, and may eventually facilitate new application areas. In this paper, the physical and mechanical properties of clay after exposure to high temperatures at two different oxygen levels and cooled in two different ways are studied. In the experiment, the clay samples are heated at high temperatures in anoxic conditions and air. The anoxic conditions are facilitated by a closed crucible. After the sample reaches the target temperature (400°C, 500°C, 600°C, 700°C, 800°C and 900°C), it is cooled to room temperature slowly in the furnace. The samples that are heated in air are either cooled in the furnace or quenched in water. Finally, the appearance of the clay samples in terms of their surface color and development of cracks, as well as their shrinkage, mass loss, hardness, strength and deformation, and the color of the core are examined and measured. The results show that the color of the surface of the clay samples heated in anoxic conditions and air significantly differs, and the color of the core is grayish black at temperatures that are below 800°C, which is possibly related to the oxidation and reduction of iron ions. Cracks in the clay samples partially offset shrinkage. The clay samples quenched in water show larger cracks and lower compressive strength. The mass of the samples does not change at temperatures that exceed 800°C. The hardness also does not change at temperatures that are higher than 700°C. In summary, temperatures between 700°C and 800°C have the most impact on clay because many of the physical properties (including their surface color and color of the core, shrinkage, mass, hardness, and strength) vary greatly at this temperature range.

scholarly journals Study on Hydration and Strengthening of High Alumina Cements

2017 ◽  
Vol 15 (12) ◽  
pp. 22-27
Author(s):  
Nicolae Angelescu ◽  
Cristina Stancu ◽  
Sofiane Amziane ◽  
Vasile Bratu ◽  
Elena Valentina Stoian
Keyword(s):  
Mechanical Properties ◽  
Binary System ◽  
High Temperatures ◽  
Refractory Concrete ◽  
Physical And Mechanical Properties ◽  
Mineralogical Composition ◽  
High Alumina ◽  
Great Success ◽  
High Refractoriness ◽  
Main Factor

Abstract Refractory concretes based on aluminous cements are used with great success in areas where high temperatures are required. The mineralogical composition of the high alumina cement is the main factor which gives the physical and mechanical properties at high temperatures of refractory monolithic materials.It is therefore desirable to use high alumina cements based on mineralogical compounds with high refractoriness, because in the end those beneficial properties can be found in the final product - refractory concrete.The aim of this paper is to design, realize and characterize different compositions of high alumina cements based on mineralogical compounds with the highest refractory from the CaO-Al2O3 binary system (i.e. CA, CA2, and CA6), and to find ways of hydraulic activation of calcium hexa aluminate, also.

scholarly journals Influences of high temperature on mechanical properties of fly ash based geopolymer mortars reinforced with PVA fiber

2021 ◽  
Vol 20 (2) ◽  
pp. 393-406
Author(s):  
Mehmet Kaya ◽  
◽  
Fuat Köksal ◽  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
High Temperatures ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Polyvinyl Alcohol Fiber ◽  
Pva Fiber ◽  
High Temperature Effect

In this study, a geopolymer composite containing PVA fiber was produced to recycle waste fly ash and obtain an eco-friendly binder. Mechanical properties of geopolymer mortars, produced by using F class fly ash which was activated with NaOH (sodium hydroxide), and reinforced by PVA (polyvinyl alcohol) fiber were investigated after high temperature effect. Geopolymer mortar samples produced by mixing with fly ash, sand, water and NaOH were placed in standard molds of 40×40×160 mm3. PVA fibers were used at percentages of 0,5%, 1% and 1,5% by volume in the experiment. Tests were performed on mortars exposed to high temperatures of 200°C, 400°C, 600°C and 800°C for physical and mechanical properties. For the specimens not subjected to high temperatures, an increase in the compressive strength of mortars containing PVA fibers was observed in comparison to mortar without PVA fiber. On the other hand, it was concluded that losses in compressive strength were less for mortar without PVA fiber when compared with the mortars containing PVA fibers. As a result of the modeling, the PVA ratio, which gives the optimum flexural and compressive strength, was determined as 1,47%. As a result of melting of PVA fibers under the effect of high temperature, 83,58% loss of compressive strength was determined in samples containing 1,5% PVA after 800ºC temperature.

Sign in / Sign up

Export Citation Format

Share Document