scholarly journals Effect of Quarry Rock Dust as a Binder on the Properties of Fly Ash and Slag-Based Geopolymer Concrete Exposed to Ambient and Elevated Temperatures

2021 ◽  
Vol 11 (19) ◽  
pp. 9192
Author(s):  
Khadim Hussain ◽  
Faheem Butt ◽  
Mamdooh Alwetaishi ◽  
Rana Muhammad Waqas ◽  
Fahid Aslam ◽  
...  
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Elevated Temperatures ◽  
Geopolymer Concrete ◽  
Residual Compressive Strength ◽  
Hardened Properties ◽  
Mechanical Strengths ◽  
Rock Dust

This study presents the performance of quarry rock dust (QRD) incorporated fly ash (FA) and slag (SG) based geopolymer concretes (QFS-GPC) exposed to ambient and elevated temperatures. A total of five QFS-GPC mix types were prepared. The quantity of FA (50%) was kept constant in all the mixes, and SG was replaced by 5%, 10%, 15%, and 20% of QRD. The fresh, hardened properties of the QFS-GPC mixes, viz., workability, compressive strength, splitting tensile strength, and flexural strengths, and XRD for identification of reaction phases were evaluated. The prepared mixes were also heated up to 800 °C to evaluate the residual compressive strength and weight loss. The workability of the QFS-GPC mixes was observed to be reduced by increasing the dosage (0 to 20%) of QRD. Superplasticizer (SP) was used to maintain the medium standard of workability. The compressive, tensile, and flexural strengths were increased by replacing SG with QRD up to 15%, whereas a further higher dosage (20%) of QRD reduced the mechanical strengths of the QFS-GPC mixes. The strength of the QFS-GPC specimens, heated to elevated temperatures up to 800 °C, was reduced persistently with the increased contents of QRD from 0 to 20%. It was concluded from the study that QFS-GPC can be used to achieve 30 MPa strength of concrete.

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

Materials ◽  
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).

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

2011 ◽  
Vol 250-253 ◽  
pp. 962-968 ◽  
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.

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 Research on Mechanical Performance & Behaviour of Geopolymer Concrete Subjected to Elevated Temperatures

2019 ◽  
Vol 8 (2S8) ◽  
pp. 883-887
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Geopolymer Concrete ◽  
Sem Images ◽  
Before And After ◽  
Alkaline Conditions ◽  
Compressive Strength Of Concrete

The investigative studies on mechanical performance & behaviour, of Geopolymer Concrete (GPC) before and after the exposure to elevated temperatures (of 200 0 C -1000 0 C with an increment of 100 0 C). Indicate that the GPC Specimens Exhibited better Compressive strength at higher temperatures than that of those made by regular OPC Concrete with M30 Grade. The chronological changes in the geopolymeric structure upon exposure to these temperatures and their reflections on the thermal behaviour have also been explored. The SEM images indicate GPC produced by fly ash , metakaolin and silica fume, under alkaline conditions form Mineral binders that are not only non-flammable and but are also non-combustible resins and binders. Further the Observations drawn disclose that the mass and compressive strength of concrete gets reduced with increase in temperatures.

scholarly journals Effect of Carboxylic Acid (Benzene Crystallable) in Cement Concrete and Geopolymer Concrete

2020 ◽  
Vol 9 (7) ◽  
pp. 472-475
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Carboxylic Acid ◽  
Geopolymer Concrete ◽  
Cement Concrete ◽  
Split Tensile Strength ◽  
Sealing Capacity ◽  
Time Period

The present study appraises the recitals of carboxylic acid- based admixture to increase concrete water tightness and self-sealing capacity of the cement and geopolymer concrete. Outcomes of the previous studies in particular, adding 1% by cement mass of the carboxylic polymer reasons for reduction in the water dispersion under pressure of 7-day wet cured concrete by 50% associated to that of the conforming reference concrete. At 7 days, M4 mix compressive strength is about 43.5% less than M3 mix. The compressive strength of M4 increases and is about 37.6% less than M3 mix at 28 days of curing. At 7 days, M4 mix split tensile strength is about 17.5% less than M3 mix (cement concrete with 0.45 w/c ratio). The split tensile strength of M4 declines and is about 42.3% less than M3 mix at 28 days of curing. The strength of the geopolymer concrete tends to increase as the time period increases due to the presence of fly ash in it. So it is expected that geopolymer concrete will give more strength than cement concrete in long term with the presence of carboxylic acid

scholarly journals Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete

2021 ◽  
Vol 30 (3) ◽  
pp. 464-476
Author(s):  
Haider Owaid ◽  
Haider Al-Baghdadi ◽  
Muna Al-Rubaye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Wood Ash ◽  
Splitting Tensile Strength ◽  
Waste Paper ◽  
Geopolymer Concrete

Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.

scholarly journals Strength and abrasion performance of recycled aggregate based geopolymer concrete

2021 ◽  
Author(s):  
Asfaw Mekonnen LAKEW ◽  
Mukhallad M. AL-MASHHADANI ◽  
Orhan CANPOLAT
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
One Year

This experimental work evaluated geopolymer concrete containing fly ash and slag by partial replacement of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) to manufacture environmental-friendly concrete. The proportion of recycled aggregates considered consists of 10%, 20%, 30%, and 40% of the total coarse aggregate amount. Also, a steel fiber ratio of 0.3% was utilized. The mechanical properties and abrasion resistance of fly ash/slag-based geopolymer concrete were then assessed. Majorly, the mechanical strength of the concrete samples decreased by the increase of RCA content. The geopolymer concrete with 40% RCA gave 28.3% lesser compressive strength and 24% lower splitting tensile strength than NCA concrete at one year. Also, the flexural strength of concrete specimens was reduced by 35% (from 5.34MPa to 3.5MPa) with the incorporation of 40% RCA. The incorporation of 30% RCA caused 23% and 22.6% reduction in compressive strength at 56 days and one year, respectively. The flexural and splitting tensile strength of the specimens was not significantly reduced (less than 10%) with the inclusion of a recycled coarse aggregate ratio of up to 30%. Furthermore, the abrasion wear thickness of every concrete sample was less than 1mm. RCA inclusion of 20% produced either insignificant reduction or better strength results compared to reference mixtures. As a result, it was considered that the combination of 0.3% steel fiber and 20% recycled coarse aggregate in fly ash/slag-based geopolymer concrete leads to an eco-friendly concrete mix with acceptable short and long-term engineering properties that would lead to sustainability in concrete production and utilization sector.

scholarly journals Behavior of Chinese Dahurian Larch Wood after High-Temperature Exposure: Degradation of Mechanical Properties and Damage Constitutive Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Qifang Xie ◽  
Lipeng Zhang ◽  
Zhenglei Yang ◽  
Long Wang ◽  
Yaopeng Wu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Constitutive Model ◽  
Elevated Temperatures ◽  
Dahurian Larch ◽  
Water Cooling ◽  
Residual Compressive Strength ◽  
Damage Constitutive Model

Wood has been extensively used in Chinese ancient buildings, and it is important to clearly understand the mechanical properties of wood after exposure to elevated temperatures. In this paper, three kinds of tests with 102 clear wood specimens fabricated with Chinese Dahurian larch for each kind of test were conducted. The residual compressive strength, tensile strength, and shear strength parallel to grain of specimens after exposure to different temperatures (100°C, 150°C, 200°C, and 250°C) with various exposure times (15 min, 30 min, and 45 min) and different cooling methods (natural cooling and water cooling) were obtained. Results indicate that exposure to elevated temperatures causes great degradation of compressive strength, tensile strength, and shear strength parallel to grain. When the exposure temperatures exceed 200°C, the relative compressive strength, tensile strength, and shear strength parallel to grain decrease greatly with the increase of exposure time. The residual compressive strength, tensile strength, and shear strength of specimens after water cooling are lower than that after natural cooling. Exposure temperatures also have a great impact on the weight loss and color change of wood. Based on the test data, degradation models for the residual compressive strength, tensile strength, and shear strength of wood were developed. Furthermore, the damage constitutive model of compressive (CDMC) and tensile (CDMT) parallel to grain was established and validated reasonably by tests.

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