Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill – Part 2: Effects of mixing time and curing temperature

In recent years, geopolymers have received significant attention because they show environmental benefits, such as a reduction in the consumption of natural resources and a decrease in the net production of CO2. In addition, as green material, soil has low carbon dioxide production emissions compared to other building materials. In this research, soil was combined with activator alkaline to produce hardening materials as geopolymer soils. An alkaline solution with sodium hydroxide, sodium silicate and fly ash was used. The influence of clay content on the geopolymer soils’ compressive strength was investigated. The best strengths were obtained from 5% to 12% clay content. SEM photos were also taken from specimens to investigate the structure of geopolymer soils. When combined with soil and fly ash in geopolymerization, fly ash reacted to the alkali solution quickly. The relationships between many variables such as clay content, fly ash, alkaline solution, curing time, and curing temperature were investigated by using a statistical analysis program with over 100 initial parameters. These results also indicate that the use of soils in geopolymer soil should have been limited. Additionally, increasing the sodium silicate in the alkaline liquid affected the geopolymerization reaction significantly. However, the suitable Si on the alkaline solution and soil should be limited.

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Autogenous Deformation of Alkali-Activated Blast Furnace Slag Concrete Subjected to Variable Curing Temperatures

Advances in Civil Engineering ◽

10.1155/2019/6903725 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Katalin Orosz ◽

Abeer Humad ◽

Hans Hedlund ◽

Andrzej Cwirzen

Keyword(s):

Blast Furnace ◽

Diffraction Analysis ◽

Sodium Silicate ◽

Blast Furnace Slag ◽

Curing Temperature ◽

X Ray Diffraction ◽

X Ray ◽

Activated Slag ◽

Furnace Slag ◽

Alkali Activated

Deformations of alkali-activated slag concrete (AASC) with high MgO and Al2O3 content, subjected to variable curing temperature were studied. Sodium silicate and sodium carbonate were used as alkali activators. The obtained results showed development of deformations consisting of both shrinkage and expansion. Shrinkage appeared not to be affected by the activator type, while the expansion developed after the cooling down phase in stabilized isothermal conditions and did not stop within the duration of the tests. X-ray diffraction analysis performed shortly after the cooling down phase indicated the formation of crystalline hydrotalcite, which was associated with the observed expansion. A mixture with a higher amount of sodium silicate showed less expansion, likely due to the accelerated hydration and geopolymerization leading to the increased stiffness of the binder matrix.

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Experimental Development of a Novel Mine Backfill Material: Foam Mine Fill

Minerals ◽

10.3390/min10060564 ◽

2020 ◽

Vol 10 (6) ◽

pp. 564

Author(s):

Mohammed Hefni ◽

Ferri Hassani

Keyword(s):

Mixing Time ◽

Working Environment ◽

Dry Density ◽

Experimental Development ◽

Hydraulic Fill ◽

Mine Backfill ◽

Air Bubble ◽

Backfill Material ◽

Bubble Structure ◽

Entrained Air

This study aims to develop a novel mine backfill material called foam mine fill (FMF). A cellular structure is achieved by incorporating a premade foam into the backfill mixture using an air-entraining agent. FMF samples were prepared with copper-nickel mine tailings and normal Portland cement. Experiments were designed to investigate the effect of binder dosage, volume of entrained air, and foam mixing time on FMF unconfined compressive strength (UCS) and dry density. Moreover, a qualitative microscopic assessment investigated the effect of foam mixing time on air bubble structure. The pore size distribution and porosity of selected samples were investigated through mercury intrusion porosimetry. Relative to reference samples without entrained air, the UCS of FMF samples was 20–50% lower. However, the concomitant lower dry density (by up to 360 kg/m3) could enhance the safety of the underground working environment, especially in underhand cut-and-fill mining where miners and machinery work beneath the backfilled stope, and lower-density fill material would minimize the adverse effects of potential backfill failure. Prolonged foam mixing time led to a significant loss in UCS and total collapse of the air bubble structure. Other potential applications for FMF are areas where there are tailings shortages and as an alternative to hydraulic fill.

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Optimum Mixture Design of Bottom Ash Based Alkali-Activated Mortar Using Artificial Neural Networks

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.452-453.733 ◽

2010 ◽

Vol 452-453 ◽

pp. 733-736

Author(s):

Su Tae Kang ◽

Hyun Jin Kang ◽

Gum Sung Ryu ◽

Gyung Taek Koh ◽

Jang Hwa Lee

Keyword(s):

Neural Networks ◽

Artificial Neural Networks ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Experimental Studies ◽

Bottom Ash ◽

Mixture Design ◽

Curing Temperature ◽

Artificial Neural ◽

Alkali Activated

Bottom ash based alkali-activated mortar is prepared by incorporating sodium hydroxide and sodium silicate with some additional water if needed, and is activated with temperature curing. This research was conducted to derive an optimum mixture design of the bottom ash based alkali-activated mortar. The experimental studies were first performed to estimate the effect of the added water content, alkali activator to bottom ash ratio, sodium silicate to sodium hydroxide ratio as well as curing temperature on workability and strength. In order to optimize the mix proportion, based on the experimental results, artificial neural networks were introduced.

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Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.699.15 ◽

2014 ◽

Vol 699 ◽

pp. 15-19 ◽

Cited By ~ 4

Author(s):

Rosniza Hanim Abdul Rahim ◽

Khairun Azizi Azizli ◽

Zakaria Man ◽

Muhd Fadhil Nuruddin

Keyword(s):

Compressive Strength ◽

Elevated Temperature ◽

Fly Ash ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Room Temperature ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Curing Temperature ◽

Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

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Flood Mud as Geopolymer Precursor Materials: Effect of Curing Regime on Compressive Strength

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.815.177 ◽

2015 ◽

Vol 815 ◽

pp. 177-181 ◽

Cited By ~ 1

Author(s):

Mohd Mustafa Al Bakri Abdullah ◽

Mukridz Md Mohtar ◽

Liew Yun Ming ◽

Muhammad Faheem Mohd Tahir ◽

Kamarudin Husin ◽

...

Keyword(s):

Compressive Strength ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Strength Properties ◽

Sem Analysis ◽

Raw Material ◽

Curing Temperature ◽

Strength Tests ◽

Maximum Compressive Strength ◽

Curing Regime

This paper studies the effect of curing temperature and curing duration to the flood mud based geopolymer on compressive strength properties. Flood mud was used as a raw material for geopolymer and geopolymer samples were synthesized by using sodium silicate and sodium hydroxide 14M solution. These samples were cured at different temperature (100°C, 150°C, 200°C and 250°) for different curing duration (6h, 12h and 24h) respectively. Compressive strength tests were carried out at after 28 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Result showed that the maximum compressive strength was 24 MPa at temperature of 150°C for 24 hours. With increasing ageing day, densification of geopolymer gel was observed.

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Hybrid Mold: Comparative Study of Rapid and Hard Tooling for Injection Molding Application Using Metal Epoxy Composite (MEC)

Materials ◽

10.3390/ma14030665 ◽

2021 ◽

Vol 14 (3) ◽

pp. 665

Author(s):

Radhwan Hussin ◽

Safian Sharif ◽

Marcin Nabiałek ◽

Shayfull Zamree Abd Rahim ◽

Mohd Tanwyn Mohd Khushairi ◽

...

Keyword(s):

Injection Molding ◽

New Product Development ◽

Epoxy Composite ◽

Mixing Time ◽

Mold Insert ◽

Physical And Mechanical Properties ◽

Critical Factor ◽

Curing Temperature ◽

Mass Composition ◽

Control Factors

The mold-making industry is currently facing several challenges, including new competitors in the market as well as the increasing demand for a low volume of precision moldings. The purpose of this research is to appraise a new formulation of Metal Epoxy Composite (MEC) materials as a mold insert. The fabrication of mold inserts using MEC provided commercial opportunities and an alternative rapid tooling method for injection molding application. It is hypothesized that the addition of filler particles such as brass and copper powders would be able to further increase mold performance such as compression strength and thermal properties, which are essential in the production of plastic parts for the new product development. This study involved four phases, which are epoxy matrix design, material properties characterization, mold design, and finally the fabrication of the mold insert. Epoxy resins filled with brass (EB) and copper (EC) powders were mixed separately into 10 wt% until 30 wt% of the mass composition ratio. Control factors such as degassing time, curing temperature, and mixing time to increase physical and mechanical properties were optimized using the Response Surface Method (RSM). The study provided optimum parameters for mixing epoxy resin with fillers, where the degassing time was found to be the critical factor with 35.91%, followed by curing temperature with 3.53% and mixing time with 2.08%. The mold inserts were fabricated for EB and EC at 30 wt% based on the optimization outcome from RSM and statistical ANOVA results. It was also revealed that the EC mold insert offers better cycle time compared to EB mold insert material.

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Geo-polymerization mechanism and factors affecting it in Metakaolin-slag-fly ash blended concrete

E3S Web of Conferences ◽

10.1051/e3sconf/202018401080 ◽

2020 ◽

Vol 184 ◽

pp. 01080

Author(s):

A D Sandeep Kumar ◽

Dinesh Singh ◽

V Srinivasa Reddy ◽

Kaveli Jagannath Reddy

Keyword(s):

Fly Ash ◽

Sodium Silicate ◽

Curing Temperature ◽

Polymer Concrete ◽

Geopolymer Concrete ◽

Temperature Ratio ◽

Factors Affecting ◽

Polymerization Mechanism ◽

Excess Water ◽

Source Materials

This paper presents the mechanism and chemistry behind the geo-polymerization and its application in development of Geo-polymer concrete. In this paper, guidelines to develop a geo-polymer concrete is discussed along with the factors affecting the geopolymerization process in concrete. It is concluded that curing temperature, ratio of alkaline liquids , chemical ratio of silicate and sodium in sodium silicate, alkaline liquids / Si-Al source materials ratio, sodium silicate/ hydroxyl ions ratio, presence of calcium, presence of excess water and Si/Al ratio in source materials have significant effect on the development of geopolymer concrete and its performance.

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