Effects of metakaolin and sodium silicate solution on workability and compressive strength of sustainable Geopolymer mortar

Geopolymer concrete (GPC) has been used as a partial replacement of Portland cement concrete (PCC) in various construction applications. In this paper, two artificial intelligence approaches, namely adaptive neuro fuzzy inference (ANFIS) and artificial neural network (ANN), were used to predict the compressive strength of GPC, where coarse and fine waste steel slag were used as aggregates. The prepared mixtures contained fly ash, sodium hydroxide in solid state, sodium silicate solution, coarse and fine steel slag aggregates as well as water, in which four variables (fly ash, sodium hydroxide, sodium silicate solution, and water) were used as input parameters for modeling. A total number of 210 samples were prepared with target-specified compressive strength at standard age of 28 days of 25, 35, and 45 MPa. Such values were obtained and used as targets for the two AI prediction tools. Evaluation of the model’s performance was achieved via criteria such as mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The results showed that both ANN and ANFIS models have strong potential for predicting the compressive strength of GPC but ANFIS (MAE = 1.655 MPa, RMSE = 2.265 MPa, and R2 = 0.879) is better than ANN (MAE = 1.989 MPa, RMSE = 2.423 MPa, and R2 = 0.851). Sensitivity analysis was then carried out, and it was found that reducing one input parameter could only make a small change to the prediction performance.

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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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Effects of Alkaline Solution on the Properties of Slag Based Geopolymer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.877.193 ◽

2018 ◽

Vol 877 ◽

pp. 193-199 ◽

Cited By ~ 1

Author(s):

Suman Saha ◽

C. Rajasekaran

Keyword(s):

Compressive Strength ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Alkaline Solution ◽

Sodium Hydroxide Solution ◽

Setting Time ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Hydroxide Solution ◽

Geopolymer Paste

Production of Ordinary Portland Cement (OPC) requires huge quantity of natural resources and energy and it releases large amount of carbon - di - oxide to the environment. Therefore, enormous studies have been carried out throughout the world to establish geopolymer as an alternative binder material for the replacement of OPC to protect the environment. This study intends to explore the effects of alkaline solution on the properties of geopolymer produced with ground granulated blast furnace slag. Properties such as Standard consistency, setting time of slag based geopolymer paste has been determined using Vicat’s apparatus (according to the guidelines given by Indian Standards for OPC). In order to determine the effects of alkaline solution on the properties of geopolymers, the concentration of sodium hydroxide solution has been varied from 6M to 16M and the ratio of sodium silicate solution to sodium hydroxide solution is also varied from 1.0 to 2.0. Results indicate higher standard consistency and significant less setting time for slag based geopolymer paste than that of OPC paste. Compressive strength of the geopolymer paste and mortar cube samples, cured in ambient conditions till the day of testing, is increasing with the increase of the concentration of sodium hydroxide solution. Highest compressive strength is obtained for the samples prepared with alkaline solution having the ratio of sodium silicate solution to sodium hydroxide solution as 1.5. But when the concentration of sodium hydroxide solution is beyond 14M, decreasing trend in compressive strength is observed.

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Effects of Seawater Content in Alkaline Activators to Engineering Properties of Fly Ash-Based Geopolymer Concrete

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.296.105 ◽

2019 ◽

Vol 296 ◽

pp. 105-111 ◽

Cited By ~ 4

Author(s):

Quang Minh Do ◽

Thu Ha Bui ◽

Hoc Thang Nguyen

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Water Absorption ◽

Sodium Silicate ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Engineering Properties ◽

Geopolymer Concrete ◽

Special Investigation ◽

Liquid Phases

This paper illustrates a special investigation on geopolymer concrete synthesized from fly ash, sand, coarse aggregates (solid phases) in conditions of sodium silicate solution and seawater (liquid phases). The mixtures of geopolymer concrete were designed with proportion changes of among materials to evaluate effects of the proportions to engineering properties of products. The specimens were molded into cylinder with 200 mm in length and 100 mm in diameter, and then cured at room condition (28 °C, 80 % of humidity) for testing engineering properties for 7 days, 28 days, 90 days, and 180 days. The engineering properties of geopolymer concrete samples included compressive strength (MPa), water absorption (kg/m3), and volumetric weight (kg/m3). The results showed that the fly ash-based geopolymer concrete using sodium silicate solution and seawater was very good performance with value of 180 day-compressive strength at 58 MPa, water absorption and volumetric weight were at 180 kg/m3 and 2200 kg/m3, respectively.

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Fabrication and Characterization of Geopolymers from Japanese Volcanic Ashes

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.92.1 ◽

2014 ◽

Vol 92 ◽

pp. 1-7

Author(s):

Shinobu Hashimoto ◽

Hayami Takeda ◽

Tatsuya Machino ◽

Haruka Kanie ◽

Sawao Honda ◽

...

Keyword(s):

Compressive Strength ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Volcanic Ash ◽

Sodium Hydroxide Solution ◽

Water Immersion ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Hydroxide Solution ◽

Volcanic Ashes

Geopolymers were fabricated from some Japanese volcanic ashes. 30 g of volcanic ash with 200μm in diameter was mixed with 10 ml of sodium hydroxide solution with various concentrations to form slurry which became geopolymer after curing. When 8.5~11.5 mol/L of sodium hydroxide solution was used, the compressive strength of the resultant geopolymers reached to 25-35MPa. However, when the volcanic ash with high silica content was used, the compressive strength of the geopolymer was under 20 MPa. Furthermore, the addition of sodium silicate hydrate into starting slurry which was consisted of volcanic ash and sodium silicate solution had not effected on the compressive strength of geopolymer. In contrast, the compressive strength of the geopolymer decreased to 30 % of compressive strength compared to that of original geopolymer after water immersion for 3 days. However, crushing treatment of the volcanic ash contributed to retain the compressive strength. Actually, when 10μm of volcanic ash was used to fabricate geopolymer, the compressive strength improved to 70% compared to that of original geopolymer.

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The Effect of Activators on the Fly Ash-Based Geopolymers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.477.85 ◽

2011 ◽

Vol 477 ◽

pp. 85-90

Author(s):

Yun Fen Hou ◽

Dong Min Wang

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Sodium Silicate ◽

Sodium Silicate Solution ◽

Solution Concentration ◽

Silicate Solution ◽

Strength Development ◽

X Ray Diffraction ◽

Sodium Potassium ◽

Class F Fly Ash

This paper studies the influences of concentration and modulus of sodium silicate solution (Na activator) and sodium potassium silicate solution (Na-K activator) on the phase composition, microstructure and strength development in the geopolymers prepared using Class F fly ash. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and MAS NMR were utilized. It shows that the compressive strength increases while Na activator solution modulus increases, but when modulus exceeds 1.4, the compressive strength decreases, and it decreases markedly while modulus is greater than 2.0. The compressive strength improves with increase of sodium silicate solution concentration, and when concentration is 32%, compressive strength reaches the maximum, and then it reduces with concentration increment. It shows that the compressive strength increases while Na-K activator solution modulus increases, but when modulus exceeds 1.7, the compressive strength decreases, and it decreases markedly while modulus is greater than 2.0. The compressive strength improves with increase of Na-K activator solution concentration, and when concentration is 36%, compressive strength reaches the maximum. The main product of reaction in the geopolymeric material is amorphous alkali aluminosilicate gel.

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Printability and Setting Time of CSA Cement with Na2SiO3 and Gypsum for Binder Jetting 3D Printing

Materials ◽

10.3390/ma14112811 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2811

Author(s):

Okpin Na ◽

Kangmin Kim ◽

Hyunjoo Lee ◽

Hyunseung Lee

Keyword(s):

3D Printing ◽

Sodium Silicate ◽

Setting Time ◽

Sodium Silicate Solution ◽

Preliminary Test ◽

Silicate Solution ◽

Calcium Sulfoaluminate Cement ◽

Calcium Sulfoaluminate ◽

Parametric Studies ◽

Binder Jetting

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.

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Silica extraction from bauxite reaction residue and synthesis water glass

Green Processing and Synthesis ◽

10.1515/gps-2021-0028 ◽

2021 ◽

Vol 10 (1) ◽

pp. 268-283

Author(s):

Yunlong Zhao ◽

Yajie Zheng ◽

Hanbing He ◽

Zhaoming Sun ◽

An Li

Keyword(s):

Sodium Silicate ◽

Water Glass ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Hydrated Calcium Silicate ◽

Precipitated Silica ◽

Alumina Gel ◽

Silica Alumina ◽

Element Removal ◽

Hydrated Calcium

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

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A Study on a Green Route to Preparation of Silica Powders with Rice Husk Ash

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.1015 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 1015-1019

Author(s):

Ze Xin Yang ◽

Lin Dong ◽

Meng Wang ◽

Huan Li

Keyword(s):

Sodium Bicarbonate ◽

Sodium Silicate ◽

Rice Husk ◽

Rice Husk Ash ◽

Sodium Hydroxide Solution ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Raw Material ◽

Transmission Electron ◽

Thermal Analyzer

The main purpose of this article is to develop an environmentally friendly and economically effective process to produce silica from rice husk ash. Sodium silicate solution was prepared by the reaction of rice husk ash and sodium hydroxide solution, and then the sodium silicate solution was used as the raw material for the preparation of silica with sodium bicarbonate. During the reaction, the by-product can be passed into CO2 to prepare sodium bicarbonate what can be reutilized. Experimental route achieved resource recycling and environment-friendly, low energy consumption, zero emissions and so on. Meanwhile the microstructures of the silica powders were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Thermo gravimetric/Differential thermal analyzer (TG-DTA).The purity of silicon was up to 99.43% and the particle size was 200-300nm.

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Red Mud-Blast Furnace Slag-Based Alkali-Activated Materials

Sustainability ◽

10.3390/su132011298 ◽

2021 ◽

Vol 13 (20) ◽

pp. 11298

Author(s):

Alessio Occhicone ◽

Mira Vukčević ◽

Ivana Bosković ◽

Claudio Ferone

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Red Mud ◽

Blast Furnace Slag ◽

Bauxite Residue ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Waste Products ◽

Furnace Slag ◽

Alkali Activated

The aluminum Bayer production process is widespread all over the world. One of the waste products of the Bayer process is a basic aluminosilicate bauxite residue called red mud. The aluminosilicate nature of red mud makes it suitable as a precursor for alkali-activated materials. In this work, red mud was mixed with different percentages of blast furnace slag and then activated by sodium silicate solution at different SiO2/Na2O ratios. Obtained samples were characterized by chemical–physical analyses and compressive strength determination. Very high values of compressive strength, up to 50 MPa, even for high percentage of red mud in the raw mixture (70 wt.% of RM in powder mixture), were obtained. In particular, the higher compressive strength was measured for cubic samples containing 50 wt.% of RM, which showed a value above 70 MPa. The obtained mixtures were characterized by no or scarce environmental impact and could be used in the construction industry as an alternative to cementitious and ceramic materials.

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