scholarly journals Predictive Model of Setting Times and Compressive Strengths for Low-Alkali, Ambient-Cured, Fly Ash/Slag-Based Geopolymers

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 920 ◽  
Author(s):  
Supphatuch Ukritnukun ◽  
Pramod Koshy ◽  
Aditya Rawal ◽  
Arnaud Castel ◽  
Charles Christopher Sorrell
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Curing Temperature ◽  
Setting Times ◽  
Optimal Mix ◽  
High Alkalinity ◽  
Class F Fly Ash ◽  
Furnace Slag

The effects of curing temperature, blast furnace slag content, and Ms on the initial and final setting times, and compressive strengths of geopolymer paste and mortars are examined. The present work demonstrates that ambient-cured geopolymer pastes and mortars can be fabricated without requiring high alkalinity activators or thermal curing, provided that the ratios of Class F fly ash (40–90 wt%), blast furnace slag (10–60 wt%), and low alkalinity sodium silicate (Ms = 1.5, 1.7, 2.0) are appropriately balanced. Eighteen mix designs were assessed against the criteria for setting time and compressive strength according to ASTM C150 and AS 3972. Using these data, flexible and reproducible mix designs in terms of the fly ash/slag ratio and Ms were mapped and categorised. The optimal mix designs are 30–40 wt% slag with silicate modulus (Ms) = 1.5–1.7. These data were used to generate predictive models for initial and final setting times and for ultimate curing times and ultimate compressive strengths. These projected data indicate that compressive strengths >100 MPa can be achieved after ambient curing for >56 days of mixes of ≥40 wt% slag.

scholarly journals Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3448
Author(s):  
Chenhui Jiang ◽  
Aiying Wang ◽  
Xufan Bao ◽  
Zefeng Chen ◽  
Tongyuan Ni ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Portland Cement ◽  
Adhesive Strength ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Rapid Test ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This paper presents an experimental investigation on geopolymer coatings (GPC) in terms of surface protection of civil structures. The GPC mixtures were prepared with a quadruple precursor simultaneously containing fly ash (FA), ground granulated blast-furnace slag (GBFS), metakaolin (MK), and Portland cement (OPC). Setting time, compressive along with adhesive strength and permeability, were tested and interpreted from a perspective of potential applications. The preferred GPC with favorable setting time (not shorter than 120 min) and desirable compressive strength (not lower than 35 MPa) was selected from 85 mixture formulations. The results indicate that balancing strength and setting behavior is viable with the aid of the multi-componential precursor and the mixture design based on total molar ratios of key oxides or chemical elements. Adhesive strength of the optimized GPC mixtures was ranged from 1.5 to 3.4 MPa. The induced charge passed based on a rapid test of coated concrete specimens with the preferred GPC was 30% lower than that of the uncoated ones. Setting time of GPC was positively correlated with η[Si/(Na+Al)]. An abrupt increase of setting time occurred when the molar ratio was greater than 1.1. Compressive strength of GPC was positively affected by mass contents of ground granulated blast furnace slag, metakaolin and ordinary Portland cement, and was negatively affected by mass content of fly ash, respectively. Sustained seawater immersion impaired the strength of GPC to a negligible extent. Overall, GPC potentially serves a double purpose of satisfying the usage requirements and achieving a cleaner future.

Effect of the Combined Using of Fly Ash and Granulated Blast Furnace Slag on Properties of Cementless Alkali-Activated Mortar

2011 ◽  
Vol 287-290 ◽  
pp. 916-921
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Mixture Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This paper examines the effects of the mixture ratio of fly ash/slag, the type of alkaline activators and curing conditions on the workability, compressive strength and microstructure of cementless alkali-activated mortar. The investigation showed that the mixture ratio of fly ash/slag and the type of alkaline activator have significant influence on the workability and strength, whereas the curing temperature has relatively poor effect. An alkali-activated mortar using a binder composed of 50% of fly ash and 50% of granulated blast furnace slag and alkaline activator made of 9M NaOH and sodium silicate in proportion of 1:1 is seen to be able to develop a compressive strength of 65 MPa at age of 28 days even when cured at ambient temperature of 20°C.

scholarly journals Mechanical properties of fly ash and blast furnace slag based alkali activated concrete using high silica modulus activator

2021 ◽  
Vol 309 ◽  
pp. 01202
Author(s):  
G.V.V. Satyanarayana ◽  
Kaparaboina Greeshma
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
High Strength ◽  
Cementitious Materials ◽  
Split Tensile Strength ◽  
High Silica ◽  
Furnace Slag ◽  
Alkali Activated

The alternative to cement is grabbing attention of inventors due to the numerous advantages with their usage. Fly Ash (FA) and Blast furnace slag (BFS) are abundantly available in bi product form. There is heavy problem in disposal and land availability for industries. So many studies are going on to reduce these problems by usage as cementitious materials in concrete adding advantages towards green concrete. It is developed that Alkali activated flyash concrete has high strength, high acid resistance and heat resistance where as Alkali activated slag concrete has rapid setting time, high strength, impermeable and improved fire resistance. In this study FA and BFS are activated with high silica modulus activator with different activator/binder ratios and binder contents. The alkali activated FA-BFS concrete is verified for workability, compressive strength, split tensile strength, and flexural strength.

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

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

scholarly journals Orthogonal Experimental Studies on Preparation of Mine-Filling Materials from Carbide Slag, Granulated Blast-Furnace Slag, Fly Ash, and Flue-Gas Desulphurisation Gypsum

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mingyue Wu ◽  
Xiangming Hu ◽  
Qian Zhang ◽  
Weimin Cheng ◽  
Zunxiang Hu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Flue Gas ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Setting Time ◽  
Fgd Gypsum ◽  
Granulated Blast Furnace Slag ◽  
Carbide Slag ◽  
Furnace Slag

Environmentally friendly and cheap composite green cementitious materials have been prepared from carbide slag, fly ash, flue-gas desulphurisation (FGD) gypsum, and granulated blast-furnace slag (GBFS) without using cement clinker. Orthogonal testing was used to investigate the effects of the raw materials on the amount of water required for reaching standard consistency and consistency, setting time, slump value, and strength of the produced materials after curing for 7 d and 28 d. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used for the analysis of the sample microstructure and hydration products as well as for the exploration of possible hydration mechanisms. We found that, among the utilised raw materials, the addition of FGD gypsum had the most significant effect on the setting time and amount of water required for reaching standard consistency and consistency, while the addition of GBFS deeply affected the slump value. The optimal activation results were obtained when the mass ratio of carbide slag : fly ash : GBFS : FGD gypsum was equal to 12.1 : 60.6 : 18.2 : 9.1.

scholarly journals Fly Ash/Blast Furnace Slag-Based Geopolymer as a Potential Binder for Mine Backfilling: Effect of Binder Type and Activator Concentration

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jingping Qiu ◽  
Yingliang Zhao ◽  
Jun Xing ◽  
Xiaogang Sun
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Reaction Products ◽  
Lower Reactivity ◽  
The Matrix ◽  
Binder Type ◽  
Source Materials ◽  
Furnace Slag

This article investigated the potential of fly ash (FA)/blast furnace slag- (BFS-) based geopolymer as a novel backfilling material. The effects of NaOH concentration and FA/BFS mass ratio were explored through XRD, FTIR, and TG-DTG analyses. The results indicated that the reaction products and strengths of geopolymer depended on the NaOH concentration and types of source materials. Slump, final setting time, and setting ratio increased as a function of FA content. However, the increase in FA content reduced the compressive strength and microstructure of the backfilling material (BM) due to the lower reactivity than BFS. Microstructure analysis reveals that the matrix tends to be denser with the BFS content and NaOH concentration increase.

The Effect of Blast Furnace Slag on Foam Concrete in Terms of Compressive Strength

2012 ◽  
Vol 587 ◽  
pp. 81-87 ◽  
Author(s):  
Zaid Shaker Aljoumaily ◽  
Norizal Noordin ◽  
Hanizam Awang ◽  
Mohammed Zuhear Almulali
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Foam Concrete ◽  
Cement Replacement ◽  
Pozzolanic Material ◽  
Class F Fly Ash ◽  
Furnace Slag ◽  
Class F

This study is a part of an on-going research studying the effect of blast furnace slag as a binder and filler replacement on the properties of fresh and hardened foam concrete. A mix having the density of 1300kg/m3 with a proportion of (1 cement:2 sand), W/C ratio of 0.45, a commercially available additive (SP-1), class F fly ash and a unprocessed blast furnace slag was used. The results show that the mix containing the slag achieved a higher compressive strength (6.31MPa at 28 days) than that of the control mix at the same age (5.81MPa). In addition, combining both slag and fly ash as a cement replacement further enhanced the compressive strength achieving higher compressive strengths. Also, a more stable mix was achieved by the slag replacement when compared to the control mix. This result concludes that the unprocessed slag is a good pozzolanic material that can be used with foam concrete.

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