Fabrication and Characterization of Geopolymers from Japanese Volcanic Ashes

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.

Effects of Alkaline Solution on the Properties of Slag Based Geopolymer

2018 ◽  
Vol 877 ◽  
pp. 193-199 ◽  
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.

scholarly journals Effect of Concentration of Sodium Hydroxide and Degree of Heat Curing on Fly Ash-Based Geopolymer Mortar

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Subhash V. Patankar ◽  
Yuwaraj M. Ghugal ◽  
Sanjay S. Jamkar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Large Change ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Test Period ◽  
Hydroxide Solution ◽  
Increase With Increase

Geopolymer concrete/mortar is the new development in the field of building constructions in which cement is totally replaced by pozzolanic material like fly ash and activated by alkaline solution. This paper presented the effect of concentration of sodium hydroxide, temperature, and duration of oven heating on compressive strength of fly ash-based geopolymer mortar. Sodium silicate solution containing Na2O of 16.45%, SiO2 of 34.35%, and H2O of 49.20% and sodium hydroxide solution of 2.91, 5.60, 8.10, 11.01, 13.11, and 15.08. Moles concentrations were used as alkaline activators. Geopolymer mortar mixes were prepared by considering solution-to-fly ash ratio of 0.35, 0.40, and 0.45. The temperature of oven curing was maintained at 40, 60, 90, and 120°C each for a heating period of 24 hours and tested for compressive strength at the age of 3 days as test period after specified degree of heating. Test results show that the workability and compressive strength both increase with increase in concentration of sodium hydroxide solution for all solution-to-fly ash ratios. Degree of heating also plays vital role in accelerating the strength; however there is no large change in compressive strength beyond test period of three days after specified period of oven heating.

scholarly journals Artificial Intelligence Approaches for Prediction of Compressive Strength of Geopolymer Concrete

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 983 ◽  
Author(s):  
Dong Dao ◽  
Hai-Bang Ly ◽  
Son Trinh ◽  
Tien-Thinh Le ◽  
Binh Pham
Keyword(s):  
Artificial Intelligence ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Steel Slag ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Partial Replacement ◽  
Geopolymer Concrete

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.

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

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
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.

Mix Design and Compressive Strength of Geopolymer Concrete Containing Blended Ash from Agro-Industrial Wastes

2011 ◽  
Vol 339 ◽  
pp. 452-457 ◽  
Author(s):  
Mohd Azreen Mohd Ariffin ◽  
Mohd Warid Hussin ◽  
Muhammad Aamer Rafique Bhutta
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Sodium Hydroxide Solution ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Palm Oil Fuel Ash ◽  
Hydroxide Solution ◽  
Fuel Ash

Geopolymer concrete is a type of amorphous alumino-silicate cementitious material. Geopolymer can be polymerized by polycondensation reaction of geopolymeric precursor and alkali polysilicates. Compared to conventional cement concrete, the production of geopolymer concrete has a relative higher strength, excellent volume stability and better durability. This paper presents the mix design and compressive strength of geopolymer concrete manufactured from the blend of palm oil fuel ash (POFA) and pulverized fuel ash (PFA) as full replacement of cement with a combination of sodium silicate and sodium hydroxide solution used as alkaline liquid. The density and strength of the geopolymer concrete with various PFA: POFA ratios of 0:100, 30:70, 50:50 and 70:30 together with sodium silicate to sodium hydroxide solution by mass at 2.5 and 1.0, are investigated. The concentrations of alkaline solution used are 14 Molar and 8 Molar. Tests were carried out on 100x100x100 mm cube geopolymer concrete specimens. Specimens were cured at room temperature and heat curing at 60°C and 90°C for 24 hours, respectively. The effects of mass ratios of PFA: POFA, the alkaline solution to PFA: POFA, ratio and concentration of alkaline solution on fresh and hardened properties of concrete are examined. The results revealed that as PFA: POFA mass ratio increased the workability and compressive strength of geopolymer concrete are increased, the ratio and concentration of alkaline solution increased, the compressive strength of geopolymer concrete increases with regards to curing condition.

Effect of Alkaline Activators to Engineering Properties of Geopolymer-Based Materials Synthesized from Red Mud

2018 ◽  
Vol 777 ◽  
pp. 508-512 ◽  
Author(s):  
Van Quang Le ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
Vo Thi Ha Quyen Pham ◽  
Thu Ha Bui ◽  
...  
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Red Mud ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
High Heat ◽  
Engineering Properties ◽  
Alumina Production

Geopolymer is an inorganic polymer material formed from alumino-silicate structures. Geopolymer has many outstanding functions in comparison with ordinary materials such as high mechanical strength, high heat and chemical resistance, and lightweight property. The engineering properties of geopolymer-based materials depend on raw materials and synthesized conditions. In which, the aluminosilicate materials having high activity and consisting of many alkaline activators have the possibility of increasing pH in geopolymer paste. In the solution of paste, aluminosilicate compounds are solubilized and then react with alkali-activated ions to form geopolymeric networks. The geopolymer can be synthesized in many different conditions depending on factors of temperature, pressure, and curing conditions. In this study, red mud (RM) was used as the main alumino resource for geopolymerization process. RM is a solid waste residue being left from the mining process of bauxite ores with caustic soda for alumina production. Its disposal remains a global issue in terms of environmental concerns. Formation of RM-based geopolymer was affected by many factors, in which, the alkaline activators are the most important factor. This research was conducted with sodium hydroxide and sodium silicate solutions to elucidate the effect of alkaline activator ratio to the engineering properties of RM-based geopolymers. The results showed that the RM-based geopolymer used sodium silicate solution has more outstanding properties than RM-based geopolymer using sodium hydroxide solution.

The Preparation of High Purity Silicon Dioxide from Boron Mud - The Solid Wastes of Boromagnesite for Producing Borax by Alkali or Soda

2011 ◽  
Vol 233-235 ◽  
pp. 1296-1300 ◽  
Author(s):  
Zhi Qiang Ning ◽  
Yu Chun Zhai ◽  
Hua Mei Duan
Keyword(s):  
Silicon Dioxide ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Technical Condition ◽  
Hydroxide Solution ◽  
High Purity Silicon ◽  
Boron Mud ◽  
Leaching Efficiency

The residual rich SiO2 slag was obtained for magnesium was leached from the boron mud by sulfuric acid. The SiO2 was leached from the residual slag by sodium hydroxide solution. The effect of the leaching temperature and the leaching time, the ratio of the sodium hydroxide solution to slag and the concentration of the sodium hydroxide solution on the leaching efficiency of SiO2 in the residual slag were also studied. The reasonable technical condition as follow : the leaching temperature is 130°C, the leaching time is 6 min, the concentration of the sodium hydroxide solution is 19mol·L-1, the ratio of the sodium hydroxide solution to slag is 2.5:1. The SiO2 leached rate can be stabilized about 85% under this condition. Silicon dioxide was produced by double carbonating the sodium silicate solution and its percentage purity is above 99%.

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

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.

scholarly journals Pressure-Induced Geopolymerization in Alkali-Activated Fly Ash

2018 ◽  
Vol 10 (10) ◽  
pp. 3538 ◽  
Author(s):  
Sol Park ◽  
Hammad Khalid ◽  
Joon Seo ◽  
Hyun Yoon ◽  
Hyeong Son ◽  
...  
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Elevated Pressure ◽  
X Ray Diffraction ◽  
27Al Mas Nmr ◽  
Alkali Activated

The present study investigated geopolymerization in alkali-activated fly ash under elevated pressure conditions. The fly ash was activated using either sodium hydroxide or a combination of sodium silicate solution and sodium hydroxide, and was cured at 120 °C at a pressure of 0.22 MPa for the first 24 h. The pressure-induced evolution of the binder gel in the alkali-activated fly ash was investigated by employing synchrotron X-ray diffraction and solid-state 29Si and 27Al MAS NMR spectroscopy. The results showed that the reactivity of the raw fly ash and the growth of the zeolite crystals were significantly enhanced in the samples activated with sodium hydroxide. In contrast, the effects of the elevated pressure conditions were found to be less apparent in the samples activated with the sodium silicate solution. These results may have important implications for the binder design of geopolymers, since the crystallization of geopolymers relates highly to its long-term properties and functionality.

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