Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature

This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel (quartz and mullite, etc.) produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures.

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Effects of Elevated Temperatures on the Compressive Strength of HFCC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.261-263.416 ◽

2011 ◽

Vol 261-263 ◽

pp. 416-420 ◽

Cited By ~ 1

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.

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Alkali activated waste fly ash as sustainable composite: Influence of curing and pozzolanic admixtures on the early-age physico-mechanical properties and residual strength after exposure at elevated temperature

Composites Part B Engineering ◽

10.1016/j.compositesb.2017.08.012 ◽

2018 ◽

Vol 132 ◽

pp. 161-169 ◽

Cited By ~ 35

Author(s):

Messina ◽

Ferone ◽

Colangelo ◽

Roviello ◽

Cioffi

Keyword(s):

Mechanical Properties ◽

Elevated Temperature ◽

Fly Ash ◽

Residual Strength ◽

Early Age ◽

Alkali Activated

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Mechanical and Microstructural Characterization of Quarry Rock Dust Incorporated Steel Fiber Reinforced Geopolymer Concrete and Residual Properties after Exposure to Elevated Temperatures

Materials ◽

10.3390/ma14226890 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6890

Author(s):

Muhammad Ibraheem ◽

Faheem Butt ◽

Rana Muhammad Waqas ◽

Khadim Hussain ◽

Rana Faisal Tufail ◽

...

Keyword(s):

Mechanical Properties ◽

Weight Loss ◽

Compressive Strength ◽

Fly Ash ◽

Mechanical Strength ◽

Elevated Temperatures ◽

Strength Properties ◽

Steel Fibers ◽

Geopolymer Concrete

The purpose of this research is to study the effects of quarry rock dust (QRD) and steel fibers (SF) inclusion on the fresh, mechanical, and microstructural properties of fly ash (FA) and ground granulated blast furnace slag (SG)-based geopolymer concrete (GPC) exposed to elevated temperatures. Such types of ternary mixes were prepared by blending waste materials from different industries, including QRD, SG, and FA, with alkaline activator solutions. The multiphysical models show that the inclusion of steel fibers and binders can enhance the mechanical properties of GPC. In this study, a total of 18 different mix proportions were designed with different proportions of QRD (0%, 5%, 10%, 15%, and 20%) and steel fibers (0.75% and 1.5%). The slag was replaced by different proportions of QRD in fly ash, and SG-based GPC mixes to study the effect of QRD incorporation. The mechanical properties of specimens, i.e., compressive strength, splitting tensile strength, and flexural strength, were determined by testing cubes, cylinders, and prisms, respectively, at different ages (7, 28, and 56 days). The specimens were also heated up to 800 °C to evaluate the resistance of specimens to elevated temperature in terms of residual compressive strength and weight loss. The test results showed that the mechanical strength of GPC mixes (without steel fibers) increased by 6–11%, with an increase in QRD content up to 15% at the age of 28 days. In contrast, more than 15% of QRD contents resulted in decreasing the mechanical strength properties. Incorporating steel fibers in a fraction of 0.75% by volume increased the compressive, tensile, and flexural strength of GPC mixes by 15%, 23%, and 34%, respectively. However, further addition of steel fibers at 1.5% by volume lowered the mechanical strength properties. The optimal mixture of QRD incorporated FA-SG-based GPC (QFS-GPC) was observed with 15% QRD and 0.75% steel fibers contents considering the performance in workability and mechanical properties. The results also showed that under elevated temperatures up to 800 °C, the weight loss of QFS-GPC specimens persistently increased with a consistent decrease in the residual compressive strength for increasing QRD content and temperature. Furthermore, the microstructure characterization of QRD blended GPC mixes were also carried out by performing scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS).

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Properties of Fly Ash Based Geopolymer Concrete Exposed to Sustained Elevated Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.962 ◽

2011 ◽

Vol 250-253 ◽

pp. 962-968 ◽

Cited By ~ 3

Author(s):

M.S. Sudarshan ◽

R.V. Ranganath

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Elevated Temperature ◽

Fly Ash ◽

Elevated Temperatures ◽

Research Work ◽

Acid Resistance ◽

Geopolymer Concrete ◽

Cement Concrete ◽

Beneficial Effects

Fly ash based geopolymer concrete is gaining importance in the context of developing alternatives to cement concrete. The research work available in the literature shows many beneficial effects of the material in terms of its high early compressive strength, tensile strength, reduced shrinkage, good acid resistance etc., However, there are very few studies carried out on the influence of sustained elevated temperature on the properties of geopolymer concrete. This paper presents the results of some of the properties of fly ash based geopolymer concrete activated using sodium silicate and sodium hydroxide and subjected to elevated temperature at 150°C, 200°C, 300°C, 400ºc under sustained durations of 1 hour, 2 hours and 4 hours. The results show that residual compressive strength is about 20% less than the normal at about 200°C itself possibly due to the development of vapour pressure formed by the non-reactive water present in the system. Beyond 2 hours of sustenance, there is not much of a difference in the properties of concrete.

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Mechanical Properties and Thermal Resistance of High Volume Fly Ash Concrete for Energy Efficiency in Building Construction

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.678.99 ◽

2016 ◽

Vol 678 ◽

pp. 99-108 ◽

Cited By ~ 3

Author(s):

B. Balakrishnan ◽

A.S.M. Abdul Awal

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Fly Ash ◽

Elevated Temperatures ◽

Value Added ◽

High Volume ◽

Building Construction ◽

Strength Development ◽

Fly Ash Concrete ◽

High Volume Fly Ash

The utilization of waste materials in concrete is one of the best value added solutions to the construction industry. With the aim of sustability development, high volume fly ash (HVFA) were tested in concrete by substituting 40, 50 and 60% of OPC with fly ash. Properties studied in this research includes fresh concrete properties, mechanical properties and the resistance of concrete exposed to high temperature. The test result indicates that HVFA concrete positively influenced the workability; however, the setting times of the concrete were longer. It has been found that the development of strength of high volume fly ash concrete was relatively slower, but ahigher strength development at later ages was observed in concrete containing HVFA. The performance of concrete at elevated temperatures reveals that concrete without any fly ash has better resistance than HVFA concrete at high temperature. The use of high volume fly ash results in an acceptable concrete performance, which grants high potential for energy saving in the building construction.

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Experimental Investigation of Post-Fire Mechanical Properties of Quenched and Tempered High Strength Steel 07MnMoVR

Volume 1B: Codes and Standards ◽

10.1115/pvp2018-84378 ◽

2018 ◽

Author(s):

Shanshan Shao ◽

Guodong Jia ◽

Luowei Cao ◽

Fakun Zhuang

Keyword(s):

Mechanical Properties ◽

Experimental Investigation ◽

Impact Toughness ◽

Residual Strength ◽

High Strength Steel ◽

Elevated Temperatures ◽

High Strength ◽

Stress Strain ◽

Duration Time ◽

Exposure Temperature

Quenched and tempered high strength steel 07MnMoVR with a better combination of mechanical properties and low susceptibility to welding crack has attracted attention for applications in engineering fields. Exposure to fire will subject steel to thermally induced environmental conditions that may alter the material’s properties. The residual strength after a fire event is important to assess the extent of the fire damage and the potential reusability of the vessel. This paper presents the details of an experimental investigation on the post-fire mechanical properties of 07MnMoVR steel. Uniaxial tension tests and Charpy impact tests were performed on coupons exposed to elevated temperatures varying from 550°C to 850°C for half an hour to 8 hours and then naturally cooled in air or cooled by water. The post-fire stress-strain curves, strength, ductility and impact toughness of 07MnMoVR steel are discussed. The results show that the yield plateau in post-fire stress-strain curves disappears when the exposure temperature is higher than 700°C. The residual yield strength and ultimate strength decrease firstly and increase afterward with increasing exposure temperature. The influences of duration time on the residual strength are considerable for exposure at 650°C. The post-fire impact toughness of 07MnMoVR steel at −20°C degrades drastically with increasing duration time when the exposure temperature reaches 700°C. The effects of cooling methods on strength and toughness become significant when the exposure temperature exceeds 750°C. The critical tempetature for the mechanical properties deterioration is 650°C. This study can provide basis data and guidelines for the fitness for service assessment of 07MnMoVR steel suffered from fire accident.

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Effect on high volume fly ash on mechanical properties of fiber reinforced concrete

Materials and Structures ◽

10.1617/13978 ◽

2004 ◽

Vol 37 (269) ◽

pp. 318-327 ◽

Cited By ~ 4

Author(s):

O. Kayali

Keyword(s):

Mechanical Properties ◽

Reinforced Concrete ◽

Fly Ash ◽

High Volume ◽

Fiber Reinforced Concrete ◽

Fiber Reinforced ◽

High Volume Fly Ash

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Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

Applied Sciences ◽

10.3390/app11073032 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3032

Author(s):

Tuan Anh Le ◽

Sinh Hoang Le ◽

Thuy Ninh Nguyen ◽

Khoa Tan Nguyen

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Elastic Modulus ◽

Fly Ash ◽

Flexural Strength ◽

Catalytic Cracking ◽

Fluid Catalytic Cracking ◽

High Alumina ◽

Geopolymer Concrete ◽

Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

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