On the incorporation of class F fly-ash to enhance the geopolymerization effects and splitting tensile strength of the gold mine tailings-based geopolymer

2021 ◽  
Vol 308 ◽  
pp. 125112
Author(s):  
Nan Zhang ◽  
Ahmadreza Hedayat ◽  
Héctor Gelber Bolaños Sosa ◽  
Roberto Pedro Huamani Bernal ◽  
Néstor Tupa ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Mine Tailings ◽  
Splitting Tensile Strength ◽  
Gold Mine ◽  
Gold Mine Tailings ◽  
Class F Fly Ash ◽  
Class F

scholarly journals A comparison between fly ash- and basic oxygen furnace slag-modified gold mine tailings geopolymers

2019 ◽  
Vol 11 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Thabo Falayi
Keyword(s):  
Fly Ash ◽  
Mine Tailings ◽  
Basic Oxygen Furnace ◽  
Gold Mine ◽  
Basic Oxygen ◽  
Gold Mine Tailings ◽  
Bof Slag ◽  
Lower Temperature ◽  
The One

AbstractFly ash (FA) and Basic oxygen furnace (BOF) slag were used to as additives in the geopolymerisation of gold mine tailings (GMT).The aim of the research was to determine the effects of the two additives on the strength formation and mechanism of metal immobilisation by modified GMT geopolymers. GMT, FA and BOF were mixed, respectively, and made into a paste with the addition of potassium hydroxide (KOH) before curing at various conditions. 50% replacement of GMT in the starting materials gave the highest unconfined compressive strength (UCS). The UCS for BOF-based geopolymer was 21.44 Mega Pascals (MPa), whilst the one for FA-based geopolymer was 12.98 MPa. The BOF-based geopolymer cured at lower temperature (70 °C) as compared to the FA-based geopolymer (90 °C). The optimum KOH concentration was 10 and 15 M for BOF- and FA-based geopolymers, respectively. BOF-based geopolymers resulted in the formation of calcium silicate hydrate (CSH) phases which contributed to higher strength; whereas in FA-based geopolymers, no new structures were formed. BOF-based geopolymers resulted in over 94% iron (Fe) immobilisation, whereas FA-based geopolymers had 76% Fe immobilisation. Fe immobilisation was via incorporation into the CSH or geopolymer structure, whilst other metal immobilisations were thought to be via encapsulation. 12-month static leaching tests showed that the synthesised geopolymers posed insignificant environmental pollution threat for long-term use.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF HDPE PLASTIC FILM FOR HERBICIDE CONTAINER USING FLY ASH CLASS F AS FILLER

2010 ◽  
Vol 9 (3) ◽  
pp. 348-354
Author(s):  
Yatim Lailun Ni’mah ◽  
Lukman Atmaja ◽  
Hendro Juwono
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Chemical Resistance ◽  
Active Material ◽  
Filler Concentration ◽  
Plastic Film ◽  
Infra Red ◽  
Class F Fly Ash ◽  
Class F

High Density Polyethylene (HDPE) plastic plays an important role in various applications, for example, it can be used as a container (bottle). Petrokimia Kayaku Company, a branch of Petrokimia Company of Gresik, produces herbicides using HDPE plastic bottles as their container. Those plastic bottles undergo degradation (kempot) for certain period of time. The aim of this research is to characterize and to synthesize the HDPE plastic film with class F fly ash as filler. The results expected from this research are producing the plastic with a better properties and durability. This research was initiated by taking the sample of HDPE plastic bottle and herbicides (containing Gramakuat, on active material parakuat dichloride) at Petrokimia Kayaku Company. Both the initial HDPE and the degraded bottles was analyzed their tensile strength and Fourier Transform-Infra Red (FTIR) spectral. The next step was to synthesize the HDPE plastic film using class F fly ash as filler and a coupling agent. The filler concentrations were 0%, 5%, 10%, 15%, and 20wt %. The best result was 5% filler concentration with tensile strength of 27.7 lbs. This HDPE film was then subjected to degradation test using pyridine solution with various concentrations (1%, 3% and 5%) for two weeks, thermal degradation at 100 °C for two weeks and chemical resistance by xylene with soak time variation of 24 h, 98 h and 168 h. The result of degradations test show that the value of tensile strength was decreased with the increase of filler consentration. The chemical resistance, however, was increased.   Keywords: degradation, filler, fly ash, HDPE, Herbicide

scholarly journals Experimental and Statistical Study on Mechanical Characteristics of Geopolymer Concrete

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1651 ◽  
Author(s):  
Yifei Cui ◽  
Kaikai Gao ◽  
Peng Zhang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Mechanical Characteristics ◽  
Statistical Hypothesis ◽  
Geopolymer Concrete ◽  
Empirical Equations ◽  
Class F Fly Ash ◽  
Class F

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.

scholarly journals Laboratory Study on the Effectiveness of Limestone and Cementitious Industrial Products for Acid Mine Drainage Remediation

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 413
Author(s):  
Abdellatif Elghali ◽  
Mostafa Benzaazoua ◽  
Hassan Bouzahzah ◽  
Bruno Bussière
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Mine Tailings ◽  
Ordinary Portland Cement ◽  
Mine Drainage ◽  
Secondary Phases ◽  
Environmental Matrices ◽  
Acid Mine ◽  
Class F Fly Ash ◽  
Class F

Acid mine tailings may affect several environmental matrices. Here, we aimed to stabilize acid-generated mine tailings using several alkaline and cementitious amendments, which were tested in columns for 361 days. The alkaline amendments consisted of 10 and 20 wt.% limestone, while the cementitious amendments consisted of different binders at a total dosage of 5 wt.% binder. The different formulations for the cementitious amendments were: 50% Kruger fly ash and 50% class F fly ash; 20% ordinary Portland cement, 40% Kruger fly ash, and 40% class F fly ash; 80% ordinary Portland cement and 20% Kruger fly ash; and 20% ordinary Portland cement, 40% Kruger fly ash, and 40% fly ash. Kinetic testing on the amendment formulations showed that the pH values increased from <2.5 to circumneutral values (~7.5). The mobility of various chemical species was greatly reduced. Cumulative Fe released from the unamended tailings was ~342.5 mg/kg, and was <22 mg/kg for the amended tailings. The main mechanisms responsible for metal(loid) immobilization were the precipitation of secondary phases, such as Fe-oxyhydroxides, physical trapping, and tailing impermeabilization.

scholarly journals Practical Prediction Models of Tensile Strength and Reinforcement-Concrete Bond Strength of Low-Calcium Fly Ash Geopolymer Concrete

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 875
Author(s):  
Chenchen Luan ◽  
Qingyuan Wang ◽  
Fuhua Yang ◽  
Kuanyu Zhang ◽  
Nodir Utashev ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Bond Strength ◽  
Prediction Models ◽  
Splitting Tensile Strength ◽  
Geopolymer Concrete ◽  
Structural Factors ◽  
Test Results ◽  
Portland Cement Concrete ◽  
Low Calcium

There have been a few attempts to develop prediction models of splitting tensile strength and reinforcement-concrete bond strength of FAGC (low-calcium fly ash geopolymer concrete), however, no model can be used as a design equation. Therefore, this paper aimed to provide practical prediction models. Using 115 test results for splitting tensile strength and 147 test results for bond strength from experiments and previous literature, considering the effect of size and shape on strength and structural factors on bond strength, this paper developed and verified updated prediction models and the 90% prediction intervals by regression analysis. The models can be used as design equations and applied for estimating the cracking behaviors and calculating the design anchorage length of reinforced FAGC beams. The strength models of PCC (Portland cement concrete) overestimate the splitting tensile strength and reinforcement-concrete bond strength of FAGC, so PCC’s models are not recommended as the design equations.

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