Bond Slip Models for Uncorroded and Corroded Steel Reinforcement in Class-F Fly Ash Geopolymer Concrete

This paper studies the statistical correlation in mechanical characteristics of class F fly ash based geopolymer concrete (CFGPC). Experimentally measured values of the compressive strength, elastic modulus and indirect tensile strength of CFGPC specimens made from class F fly ash (CFA) were presented and analyzed. The results were compared with those of corresponding ordinary Portland cement concrete (OPCC) using statistical hypothesis tests. Results illustrated that when possessing similar compressive and tensile strength, the elastic modulus for CFGPC is significantly lower than that of OPCC. The corresponding expressions recommended by standards for the case of OPCC is proved to be inaccurate when applied in the case of CFGPC. Statistical regression was used to identify tendencies and correlations within the mechanical characteristics of CFGPC, as well as the empirical equations for predicting tensile strength and elastic modulus of CFGPC from its compressive strength values. In conclusion, CFGPC and OPCC has significant differences in terms of the correlations between mechanical properties. The empirical equations obtained in this study could provide relatively accurate predictions on the mechanical behavior of CFGPC.

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Long term durability properties of class F fly ash geopolymer concrete

Materials and Structures ◽

10.1617/s11527-014-0268-9 ◽

2014 ◽

Vol 48 (3) ◽

pp. 721-731 ◽

Cited By ~ 79

Author(s):

David W. Law ◽

Andi Arham Adam ◽

Thomas K. Molyneaux ◽

Indubhushan Patnaikuni ◽

Arie Wardhono

Keyword(s):

Fly Ash ◽

Geopolymer Concrete ◽

Durability Properties ◽

Class F Fly Ash ◽

Class F

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Effect of GGBFS on Workability and Strength of Alkali-activated Geopolymer Concrete

Civil Engineering Journal ◽

10.28991/cej-2021-03091708 ◽

2021 ◽

Vol 7 (6) ◽

pp. 1036-1049

Author(s):

Gautam Kumar ◽

S. S. Mishra

Keyword(s):

Blast Furnace ◽

Fly Ash ◽

Blast Furnace Slag ◽

Geopolymer Concrete ◽

Thermal Curing ◽

Concrete Material ◽

Class F Fly Ash ◽

Furnace Slag ◽

Alkali Activated ◽

Class F

This paper focuses on the development of a concrete material by utilizing fly ash and blast furnace slag in conjunction with coarse and fine aggregates with an aim to reduce pollution and eliminate the use of energy extensive binding material like cement. Alternative binding materials have been tried with an aim to get rather an improved concrete material. Alkali-Activated Solution (AAS) made of the hydroxide and silicate solutions of sodium was adopted as the liquid binder whereas, Class F” fly ash and Ground Granulated Blast Furnace Slag (GGBFS) mixed in dry state were used as the Geopolymer Solid Binder (GSB). The liquid binder was used to synthesize the solid binder by thermal curing. The paper investigates the use, influence and relative quantities of the liquid and solid binders in the development of the alkali-activated GGBFS based Geopolymer Concrete (GPC). Varying ratios of AAS to GSB were taken to assess their optimum content. Further, different percentages of GGBFS were used as a partial replacement of Class F fly ash to determine the optimum replacement of GGBFS in the GPC. In order to assess their effects on various properties test samples of cubes, cylinders and beams were cast and tested at 3, 7, and 28 days. Thermal curing of GPC has also resorted for favorable results. It was found that AAS to GSB ratio of 0.5 and GGBFS content of 80% yielded the maximum strength with a little unfavorable effect on workability. The overall results indicated that AAS and GGBFS offer good geopolymer concrete which will find its applicability in water scarce areas. Doi: 10.28991/cej-2021-03091708 Full Text: PDF

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The Effects of Water to Solid Ratio, Activator to Binder Ratio, and Lime Proportion on the Compressive Strength of Ambient-Cured Geopolymer Concrete

Journal of the Civil Engineering Forum ◽

10.22146/jcef.43878 ◽

2019 ◽

Vol 5 (2) ◽

pp. 161 ◽

Cited By ~ 1

Author(s):

Andi Arham Adam

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Sodium Hydroxide Solution ◽

Geopolymer Concrete ◽

Solid Ratio ◽

Slaked Lime ◽

Binder Ratio ◽

Class F Fly Ash ◽

Good Workability ◽

Class F

Low calcium fly ash based Geopolymer has been proven to be one of the potential alternatives substitutes to Portland Cement not only due to its high resistance to chemical attack but also because of the vast availability of class F fly ash for raw materials. However, one of the limitations of geopolymer as the alternative binders in concrete is that the strength develops slowly under ambient condition. This paper presented the investigation of water to solid ratio, activator to binder ratio, and lime proportion on the compressive strength of ambient-cured geopolymer concrete. To develop sufficient strength at an early age, class F fly ash and slaked lime (Ca (OH)2) were used as the binder with the proportion of lime to binder of 4%, 5%, 6%, and 7%. The blended binder was activated by sodium silicate and sodium hydroxide solution with the variation of activator to binder ratio of 0.45, 0.5, 0.55, and 0.6. The water to solid ratio of 0.30, 0.31, 0.32, and 0.33 was chosen to facilitate good workability which was done by adding water to the mix. The compressive strength tests were conducted at 7, 14, and 28 days on the cylindrical concrete specimens with a dimension of 100 mm diameter and 200 mm height. The results show that the activator to binder ratio of 0.50 to 0.55, and the proportion of lime to the binder of 6% to 7% were the optimum range value. It was also found that the lower the water to cement ratio the higher the compressive strength and the water to solid ratio as low as 0.3 produced the highest compressive strength while still maintaining good workability.

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