scholarly journals Effect of Elevated Temperatures on Fiber Reinforced Self Compacting Concrete

2019 ◽  
Vol 8 (3) ◽  
pp. 7775-7778
Keyword(s):  
Compressive Strength ◽  
Temperature Effects ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Steel Fibers ◽  
Muffle Furnace ◽  
Self Compacting Concrete ◽  
Retention Period ◽  
Steel Fibres ◽  
Different Temperatures

The present investigation is mainly focused on study the temperature effects on SCC reinforced with steel fibers on M40 grade of concrete. The main objective of the investigation is inspired from the real world - to know the strength of a concrete after subjected to an elevated temperature. Steel fibres with an aspect ratio of 40varied at a fibre dosage of 0, 1, and 1.5%by the weight of the cement used in this investigation. In this study concrete is exposed to five different residual conditions. In addition to the room temperature there are four different temperatures of 100˚c, 300˚c, 500˚c and 800˚c are considered at a retention period of 1, 2, 3 and 4 hours in muffle furnace. Compressive strength conducted after 28 days of curing. From the experimental results it is observed that SCC with steel fibres reduced the workability on the contrary there is increase in compressive strength observed with the addition of fibres. It is also observed that SCC with steel fibres has shown the better performance compared to control mix at elevated temperatures. This is mainly due to fibres are participated in delaying the cracks.

Effects of Elevated Temperatures on the Compressive Strength of HFCC

2011 ◽  
Vol 261-263 ◽  
pp. 416-420 ◽  
Author(s):  
Fu Ping Jia ◽  
Heng Lin Lv ◽  
Yi Bing Sun ◽  
Bu Yu Cao ◽  
Shi Ning Ding
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Relative Strength ◽  
Ordinary Concrete ◽  
Residual Compressive Strength ◽  
Fly Ash Concrete ◽  
The Relationship

This paper presents the results of elevated temperatures on the compressive of high fly ash content concrete (HFCC). The specimens were prepared with three different replacements of cement by fly ash 30%, 40% and 50% by mass and the residual compressive strength was tested after exposure to elevated temperature 250, 450, 550 and 650°C and room temperature respectively. The results showed that the compressive strength apparently decreased with the elevated temperature increased. The presence of fly ash was effective for improvement of the relative strength, which was the ratio of residual compressive strength after exposure to elevated temperature and ordinary concrete. The relative compressive strength of fly ash concrete was higher than those of ordinary concrete. Based on the experiments results, the alternating simulation formula to determine the relationship among relative strength, elevated temperature and fly ash replacement is developed by using regression of results, which provides the theoretical basis for the evaluation and repair of HFCC after elevated temperature.

scholarly journals Experimental Study on the Effect of Basalt Fiber and Sodium Alginate in Polymer Concrete Exposed to Elevated Temperature

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 510
Author(s):  
Seyed Esmaeil Mohammadyan-Yasouj ◽  
Hossein Abbastabar Ahangar ◽  
Narges Ahevani Oskoei ◽  
Hoofar Shokravi ◽  
Seyed Saeid Rahimian Koloor ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Vinyl Ester ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Basalt Fiber ◽  
Polymer Concrete ◽  
Strength Increase ◽  
Extensive Literature ◽  
Polymer Binders ◽  
Preliminary Phase

Polymer concrete contains aggregates and a polymeric binder such as epoxy, polyester, vinyl ester, or normal epoxy mixture. Since polymer binders in polymer concrete are made of organic materials, they have a very low heat and fire resistance compared to minerals. This paper investigates the effect of basalt fibers (BF) and alginate on the compressive strength of polymer concrete. An extensive literature review was completed, then two experimental phases including the preliminary phase to set the appropriate mix design, and the main phase to investigate the compressive strength of samples after exposure to elevated temperatures of 100 °C, 150 °C, and 180 °C were conducted. The addition of BF and/or alginate decreases concrete compressive strength under room temperature, but the addition of BF and alginate each alone leads to compressive strength increase during exposure to heat and increase in the temperature to 180 °C showed almost positive on the compressive strength. The addition of BF and alginate both together increases the rate of strength growth of polymer concrete under heat from 100 °C to 180 °C. In conclusion, BF and alginate decrease the compressive strength of polymer concretes under room temperature, but they improve the resistance against raised temperatures.

Mechanical Behavior of 2D C/SiC Composites at Elevated Temperatures under Uniaxial Compression

2011 ◽  
Vol 462-463 ◽  
pp. 1-6 ◽  
Author(s):  
Tao Suo ◽  
Yu Long Li ◽  
Ming Shuang Liu
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Carbon Fiber ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Carbon Matrix ◽  
Structural Applications ◽  
Sic Composites

As Carbon-fiber-reinforced SiC-matrix (C/SiC) composites are widely used in high-temperature structural applications, its mechanical behavior at high temperature is important for the reliability of structures. In this paper, mechanical behavior of a kind of 2D C/SiC composite was investigated at temperatures ranging from room temperature (20C) to 600C under quasi-static and dynamic uniaxial compression. The results show the composite has excellent high temperature mechanical properties at the tested temperature range. Catastrophic brittle failure is not observed for the specimens tested at different strain rates. The compressive strength of the composite deceases only 10% at 600C if compared with that at room temperature. It is proposed that the decrease of compressive strength of the 2D C/SiC composite at high temperature is influenced mainly by release of thermal residual stresses in the reinforced carbon fiber and silicon carbon matrix and oxidation of the composite in high temperature atmosphere.

The Effects of Winding Angles and Elevated Temperatures on the Crushing Behaviour of Glass Fibre/Epoxy Composite Pipes

2014 ◽  
Vol 695 ◽  
pp. 639-642
Author(s):  
S.N. Fitriah ◽  
M.S. Abdul Majid ◽  
R. Daud ◽  
Mohd Afendi
Keyword(s):  
Compressive Strength ◽  
Glass Fibre ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Testing Machine ◽  
Universal Testing ◽  
Glass Fibre Reinforced ◽  
Crushing Behavior ◽  
Composite Pipes ◽  
Winding Angle

The paper discusses the crushing behavior of various winding angles of glass fibre reinforced epoxy (GRE) pipes at elevated temperatures. Two different winding angles of composite pipes were chosen for the study; ± 55°, ± 63°. GRE pipes angled ± 55° and ± 63° are compressed using Universal Testing Machine (UTM) at room temperature and elevated temperatures of 45°C, 65°C, and 95°C according to ASTM D695-10 standard. The temperatures were chosen based on the glass transition temperature (Tg) that was measured earlier. The results show that as the temperature is increased, the compressive strength significantly degraded. This is due to the change in the properties of the GRE pipe from a rigid state to a more rubbery state as the composite pipe reached Tg. GRE pipe with winding angle ± 55° show a higher compressive strength compared to ± 63°.

The Compression Set Behavior of Nitrile Rubber

1973 ◽  
Vol 46 (1) ◽  
pp. 305-330 ◽  
Author(s):  
H-J. Jahn ◽  
H-H. Bertram
Keyword(s):  
Test Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Nitrile Rubber ◽  
Compression Set ◽  
Test Pieces ◽  
Steep Part ◽  
Cure Time ◽  
Different Temperatures ◽  
Lower Test

Abstract The compression set (C.S.) of a vulcanizate depends on the formulation, processing, and conditions of cure. The following factors are the most important: (a) the type of elastomer, (b) the curing system, (c) the type and amount of filler, (d) the type and amount of plasticizer, (e) the type and amount of antioxidant, (f) the type of cure (press, steam, or hot air), and (g) the cure time and temperature. The present paper is intended, as far as possible, to describe these relationships quantitatively. Most tests will refer to nitrile rubber. We have modified the C.S. method described in ASTM D-395. The deviations are as follows : (1) When C.S. is plotted as a function of the duration of compression, the resulting curves rise steeply for roughly the first seven days, afterwards becoming flatter. The higher the test temperature, the steeper the curve. The ordinary compression times of 22 and 70 h still correspond to the steep part of the C.S. curve; here relatively small inaccuracies in the compression time and test temperature bring large errors in the C.S. readings. Therefore, to improve the correlation between C.S. readings and field behavior the test was extended to seven days in most cases. Longer test times would have been experimentally impractical. (2) As a rule, only C.S. figures relating to 20°, 70°, and 100° C are found in the literature, so test temperatures were extended to include practical conditions. Generally, therefore, C.S. readings were taken at twelve different temperatures ranging from −60° C to +160° C. (3) According to the standards the test pieces should be cooled to room temperature after removal of the load and before the recovery measurement is carried out. Only ASTM D-1229-62 requires the remeasurement to be taken at the load temperature. This ensures accurate measurements of the C.S. at low temperatures. In our tests this was done in every case because at high temperature the C.S. readings are lower since (1) many elastomers recover better at elevated temperatures than at room temperature and (2) the thermal expansion of the test piece can be measured in addition to the recovery. Nevertheless, the differences between remeasurements taken at room temperature and the test temperature are small if the test temperature is fairly high. Where lower test temperatures are used, the remeasurement should always be taken at test temperature if useful results are to be obtained. In all the tests the time allowed for recovery between removal of the load and the remeasurement was thirty min.

Effects of Elevated Temperatures on the Compression Strength of Nanoclay Filled Unsaturated Polyester Resin

2014 ◽  
Vol 554 ◽  
pp. 208-212 ◽  
Author(s):  
M.S. Fartini ◽  
M.S. Abdul Majid ◽  
Mohd Afendi ◽  
N.A.M. Amin ◽  
Azizul Mohamad
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Unsaturated Polyester ◽  
Polyester Resins ◽  
Weight Percentage ◽  
Compression Properties ◽  
Strain Behaviour ◽  
Compressive Tests

The paper describes the effects of the montmorillonite (MMT) fillers commonly known as nanoclay, on the compression properties of unsaturated polyester resins at different weight percentage of nanoclay. Modified resin specimens with 1, 3 and 5 wt. % of nanoclay contents were prepared and subjected to compressive tests according to ASTM D695. The static uniaxial compression testing were conducted at various temperatures ranging from room temperature (RT) to the temperature closer to its glass transition temperature Tg to study the effect of nanoclay fillers on the compressive stress-strain behaviour at high temperatures (room temperature, 35, 45, and 75°C). The mechanical properties of the nanomodified resin including the elastic modulus, maximum stress and failure strain were determined. The experimental results imply that adding these nanoclay fillers has enhanced the elastic modulus, compressive strength, and toughness without sacrificing the strain to failure and thermal stability of the unsaturated polyester. However it was found that generally, all specimens showed degradation in compressive strength with increases in temperatures.

An Ultrasonic Non-Contact Handling Device from Quartz Glass for Middle and High Temperature Applications

2014 ◽  
Vol 1018 ◽  
pp. 31-38
Author(s):  
Edgars Locmelis
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Manufacturing Processes ◽  
Mechanical Contact ◽  
High Temperature Region ◽  
Handling Device ◽  
Design And Manufacturing ◽  
Different Temperatures ◽  
Small Change

Ultrasonic non-contact handling is used to manipulate surface sensitive and fragile workpieces, e.g. wafers and glass plates, without mechanical contact. While the technology is available forapplications at room temperature, some of the manufacturing processes of products mentioned aboverequire handling at elevated temperatures. To enable this technology for handling in thermal processesan ultrasonic system for increased working temperatures is required. In order to adapt the ultrasonicsystem to the limited working temperature of the actuator, the handling system has to be operated attwo different temperatures. Due to the small change of the Young's modulus over temperature, quartzglass was chosen as material for the components in the high temperature region. The paper presentsthe design and manufacturing of a novel ultrasonic system operated at 790 °C while the actuator iskept at room temperature.

Wandering of Crosslinks in Rubber at High Temperature

1959 ◽  
Vol 32 (3) ◽  
pp. 696-700
Author(s):  
M. J. Voorn ◽  
J. J. Hermans
Keyword(s):  
Stress Relaxation ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Crosslinking Density ◽  
Heat Treated Sample ◽  
Equilibrium Degree ◽  
Heat Treated ◽  
Before And After ◽  
Final Stress ◽  
Different Temperatures

Abstract There are strong reasons to believe that on heating a crosslinked rubber crosslinks are broken and new ones formed. This has been established by the well-known work on stress relaxation of Tobolsky and his school, and others. In the following we will discuss some experiments which give further support to these views, both of a qualitative and quantitative nature. In the first place, we carried out a few preliminary experiments on stress relaxation at elevated temperatures. This stress relaxation may be due to either or both of two effects : (a) a displacement of the crosslinks, (b) a change in the number of crosslinks per unit of volume (crosslinking density p). A measure of ρ can be obtained from the equilibrium degree of swelling at room temperature, and this gives us a means of comparing changes of ρ in a stretched sample with those occurring in the unstretched state. To this end commercial rubber strips were heated in the stretched state in the absence of oxygen at three different temperatures (80, 106, 122° C) for times varying from 2 to 72 hours. The degree of stretch, i.e., the length of the stretched rubber divided by the original length was α=1 (unstretched) in one series, and α=3 in a second series. The initial stress τ0 (for α=3) and the final stress τ at the end of the heating period were read from the stress-strain diagrams, taking into account that for the heat-treated strips there was a permanent set. In other words, τ is the stress needed to give the heat-treated sample at room temperature a length 3 times the length of the original untreated sample; the ratio τ/τ0 is therefore essentially the ratio between the moduli of elasticity. The cross-linking densities ρ0 and ρ before and after heating were derived from swelling experiments (for details see the sections on swelling).

scholarly journals Effect of Steel Fiber Aspect Ratio on the Properties of High Strength Self Compacting Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 2938-2941
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Fibers ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Strength Concrete ◽  
Fiber Aspect Ratio ◽  
Aspect Ratios ◽  
Hardened Properties

The High strength concrete defined as per IS 456 as the concrete having characteristic compressive strength more than 65 MPa. The self-compacting concrete has lot of advantages including concreting at congested reinforcement locations, better finish, good compaction etc. The inclusion of fibers in the concrete mix decreases the brittle nature of concrete thereby the ductility increases. Different types of fibers are available for inclusion in concrete like steel, glass, polypropylene, basalt, etc. In the present investigation, high strength concrete having characteristic strength of 90 MPa was developed and hooked ended steel fibers are used and the hardened properties are determined. Steel fibers having diameter of 1 mm and lengths of 25 and 50 mm were added to concrete in 0.125%, 0.25% and 0.5% by volume of concrete. Three hardened properties compressive strength, split tensile Strength and flexural strength were determined. Out of the two lengths of fiber i.e with two aspect ratios, the fiber with 50 mm length yielded better results.

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