The Mechanical Properties and Thermal Resistance of Fly Ash Geopolymer Foams

2018 ◽  
Vol 281 ◽  
pp. 175-181
Author(s):  
Hui Teng Ng ◽  
Cheng Yong Heah ◽  
Yun Ming Liew ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Compressive Strength ◽  
High Temperature ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Thermal Resistance ◽  
Bulk Density ◽  
Room Temperature ◽  
Heating Up

In the present work, a comparative study of the thermal performance of unfoamed and foamed geopolymers was investigated. The geopolymers were prepared by mixing fly ash with alkali activator (a mixture of sodium hydroxide and sodium silicate). The geopolymer foams were prepared by adding hydrogen peroxide (H2O2, 2wt.% and 4wt.%). The geopolymers were cured at room temperature (29°C) for 24 hours and at 60°C for another 24 hours. The bulk density and compressive strength decreased with increasing H2O2 up to 2wt.% and increased when 4wt.% of H2O2 was added. In order to test the thermal resistance, the geopolymers were heated at elevated temperature (200- 1000°C). Unheated geopolymers showed bulk density and compressive strength in the range of 1.6– 1.7g/cm3 and 15–17MPa, respectively. When heated up to 1000°C, the geopolymers could withstand high temperature without any disintegration and spalling. Both unfoamed and foamed geopolymers showed highest compressive strength at 200°C (17–22MPa). Further decreased in compressive strength was observed upon heating up to 800°C (10–17MPa). The compressive strength regained (14–21MPa) when heated up to 1000°C. The compressive strength was even higher than that recorded at room temperature. In the present work, unfoamed geopolymers showed overall higher thermal resistance than foamed geopolymers.

scholarly journals Influence of curing age on high-temperature properties of additive manufactured geopolymer mortar

2020 ◽  
Vol 218 ◽  
pp. 03019
Author(s):  
Xiaohong Yin ◽  
Xiaodong Wang ◽  
Yuan Fang ◽  
Zhu Ding
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Flexural Strength ◽  
High Temperature Properties ◽  
Before And After ◽  
3D Printed ◽  
Curing Age

Some researches have been conducted on the application of geopolymer in 3D printing. However, there is no publication about the high-temperature properties of 3D printed geopolymer made from fly ash, slag, and metakaolin. This paper presents the experimental research on the mechanical properties of 3D printed geopolymer after being exposed to elevated empratures. The effects of curing age on high-temperature properties are analyzed. The heating temperasures were 300 °C, 600 °C, and 900 °C, and the holding time was one hour. After exposure to temperatures, the flexural strength of 3D printed geopolymer exhibited different change trends with increasing curing age for different exposure temperatures. Before and after exposure to elevated temperature, the 3D printed geopolymer experienced significant anisotropic compressive strengths. The change trends of compressive strength at different exposure temperatures wit hincreasing curing ages were different from each other on different loading directions.

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.

Thermal Resistance of Fly Ash Geopolymers with Alumina as Additive

2018 ◽  
Vol 281 ◽  
pp. 182-188
Author(s):  
Yong Sing Ng ◽  
Yun Ming Liew ◽  
Cheng Yong Heah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Thermal Resistance ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Strength Degradation ◽  
Alumina Addition ◽  
Higher Temperature ◽  
Temperature Exposure

The present work investigates the effect of alumina addition on the thermal resistance of fly ash geopolymers. Fly ash geopolymers were synthesised by mixing fly ash with activator solution (A mixture of 12M sodium hydroxide and sodium silicate) at fly ash/activator ratio of 2.5 and sodium silicate/sodium hydroxide ratio of 2.5. The alumina (0, 2 and 4 wt %) was added as an additive. The geopolymers were cured at room temperature for 24 hours and 60°C for another 24 hours. After 28 days, the geopolymers was heated to elevated temperature (200 - 1000°C). For unexposed geopolymers, the addition of 2 wt % of alumina increased the compressive strength of fly ash geopolymers while the strength decreased when the content increased to 4 wt.%. The temperature-exposed geopolymers showed enhancement of strength at 200°C regardless of the alumina content. The strength reduced at higher temperature exposure (> 200°C). Despite the strength degradation at elevated temperature, the strength attained was relatively high in the range of 13 - 45 MPa up to 1000°C which adequately for application as structural materials.

scholarly journals Characterization and Comparison of Geopolymer Synthesized Using Metakaolin Bangka and Metastar as Precursors

2018 ◽  
Vol 67 ◽  
pp. 03022
Author(s):  
Sotya Astutiningsih ◽  
Dicky Tambun ◽  
Ahmad Zakiyuddin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Mechanical Test ◽  
Strength Test ◽  
Thermal Activity ◽  
Metallurgical Properties ◽  
Metakaolin Geopolymer ◽  
Kaolin Deposit

Various aluminosilicate material have been used as precursor for geopolymer. Geopolymer gets its strength from the polycondensation of silicate and alumina. Metakaolin, calcinated kaolin, is pozzolan with the highest alumina and silicate purity. Indonesia, especially Bangka Island, has a large amount of kaolin deposit that being sold at low price. This price could be increased ten times when being sold as metakaolin. This study aimed to compare mechanical and metallurgical properties of commercial metakaolin and Bangka kaolin which calcinated at 700°C. Both metakaolins reacted with NaOH and waterglass as the activator followed by curing at room temperature for 7, 14 and 28 days and elevated temperature of 60°C for 4, 12 and 24 hours. Mechanical properties will be examined by compressive strength and flexural strength test, while the metallurgical properties will be evaluated with SEM, and TAM. The results of the mechanical test will be used to determine which geopolymer will perform well with the microstructure and thermal activity to support the finding. These attempts will be done in order to improve the properties of Bangka metakaolin geopolymer superior to commercial metakaolin.

Research on Barite Concrete Mixed with Fly Ash

2013 ◽  
Vol 275-277 ◽  
pp. 2107-2111
Author(s):  
Qiu Lin Zou ◽  
Jun Li ◽  
Zhen Yu Lai
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Apparent Density ◽  
Cycle Times ◽  
Residual Compressive Strength ◽  
Temperature Performance

Barite concrete with density grade of 3 and strength grade of C30 was prepared by mixing with different fineness of fly ash. The workability, mechanical properties and long-term high temperature performance of the prepared barite concrete were researched. Results show that the workability of barite concrete is improved by mixing with fly ash, and no segregation of mixture has been observed. The apparent density and 3d, 28d compressive strength of barite concrete are decreased obviously after mixing with fly ash. But with the increasing of the fineness of fly ash, the apparent density and 3d, 28d compressive strength of barite concrete have a slight increase. High temperature residual compressive strength is decreased with the increasing of temperature. The cycle times of heat treatment at 400°C only has a little effect on residual compressive strength of barite concrete.

Deformation of an extruded nickel beryllide between room temperature and 820 °C

1991 ◽  
Vol 6 (12) ◽  
pp. 2653-2659 ◽  
Author(s):  
G.M. Pharr ◽  
S.V. Courington ◽  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flow Stress ◽  
Strain Hardening ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Tension And Compression ◽  
Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

A Method for the Production of Large Sized Al-B4C-Al2O3np Nanocomposites through Liquid-State Process

2017 ◽  
Vol 753 ◽  
pp. 84-92
Author(s):  
Wei Liu ◽  
Qiu Lin Li ◽  
Wei Liu ◽  
Guo Gang Shu ◽  
Qi Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Ball Milling ◽  
Liquid State ◽  
Room Temperature ◽  
Milling Time ◽  
Mixed Powder ◽  
State Process ◽  
Semi Solid

The paper introduces a new method to produce large sized Al-B4C-Al2O3np composites, which combines ball milling to prepare Al2O3np/Al mixed powder and semi-solid casting to contribute the injection of Al2O3np/Al mixed powder into the melt. The deformation performance of Al2O3np and micro-Al through ball milling with different Al/Al2O3np ratios, different milling time and different balls were studied respectively. It was revealed that micro-Al particles were milled from twisted and crimpled foil pieces to shuttles with Al2O3np embedded on it through 4h milling with 10mm balls. And we consider it as the best bonding between Al2O3np and micro-Al we could attain. And a plate of 25kg of Al-B4C-Al2O3np composite was fabricated successfully with the injection of the Al2O3np/Al mixed powder. Spherical Al2O3np of 300nm and needle-like TiB2 with 200nm in radius and 800nm-4μm in length were found in SEM photographs. Tensile properties of Al-B4C-Al2O3np composites were tested at room temperature and high temperature. It was showed higher mechanical properties than Al-B4C composites at room temperature and elevated temperature. Particularly, a 40% increase of UTS of Al-15wt.% B4C-1wt.%Al2O3np at 350°C was observed.

The Effect of Fly Ash on Lime Mortar on Elevated Temperature

2013 ◽  
Vol 684 ◽  
pp. 172-176
Author(s):  
Alireza Ghaffari ◽  
Amirreza Ghaffari
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Clay Soils ◽  
Lime Mortar ◽  
Curing Period ◽  
Stone Dust ◽  
Swell Potential ◽  
Lime Stone

To enhance the mechanical and compressive strength of lime mortar(lime-sand ) the fly ash was added to the compound to improved the engineering performance of lime mixture .The addition of fly ash and lime stone dust to clay soils reduce their plasticity characteristics, swell potential and improve their compressive strength (Brooks et al. 2011) .Boardman et al (2001) observed that no significant pozzolonic activity appears to take place until 7 days of curing during their experiments at room temperature .In this research the effect of fly ash at different range from 30 to 70 percent of mix by varying lime percentage from 6 to 20 percent with thermodynamic parameters of their reaction was assessed in normal and raised temperature by curing compacted specimens in the laboratory .The compressive strength of fly ash and lime mixture are determined on curing period up to 28 days in normal state and one days on raised one .The Result portrayed that raised temperature highly boosted the compressive strength of the mix from 30 to 120 percent at different range of fly ash mixture with lime.

Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
Author(s):  
Rosniza Hanim Abdul Rahim ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Curing Temperature ◽  
Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

scholarly journals Evaluation of the Effect of Silica Fume on Amorphous Fly Ash Geopolymers Exposed to Elevated Temperature

2021 ◽  
Vol 7 (1) ◽  
pp. 9
Author(s):  
Ong Huey Li ◽  
Liew Yun-Ming ◽  
Heah Cheng-Yong ◽  
Ridho Bayuaji ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Silica Fume ◽  
Room Temperature ◽  
Lower Degree ◽  
Crystalline Phases ◽  
Alkali Activator

The properties of amorphous geopolymer with silica fume addition after heat treatment was rarely reported in the geopolymer field. Geopolymer was prepared by mixing fly ash and alkali activator. The silica fume was added in 2% and 4% by weight. The geopolymer samples were cured at room temperature for 28 days before exposed to an elevated temperature up to 1000 °C. The incorporation of 2% silica fume did not cause significant improvement in the compressive strength of unexposed geopolymer. Higher silica fume content of 4% reduced the compressive strength of the unexposed geopolymer. When subjected to elevated temperature, geopolymer with 2% silica fume retained higher compressive strength at 1000 °C. The addition of silica fume in fly ash geopolymer caused a lower degree of shrinkage and expansion, as compared to geopolymer without the addition of silica fume. Crystalline phases of albite and magnetite were formed in the geopolymer at 1000 °C.

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