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.

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.

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.

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 Partial Replacement of Fly Ash by Metakaolin on Strength Development of Fly Ash Based Geopolymer Mortar

2017 ◽  
Vol 744 ◽  
pp. 131-135 ◽  
Author(s):  
Muhammad Zahid ◽  
Nasir Shafiq ◽  
Mohd Fadhil Nuruddin ◽  
Ehsan Nikbakht ◽  
Asif Jalal
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide Solution ◽  
Base Material ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Partial Replacement ◽  
Strength Development ◽  
Class C ◽  
Class F

This article aims to investigate the compressive strength variation by the addition of metakaolin as a substitute of fly ash in the fly ash based geopolymer mortar. Five, ten and fifteen percent by weight of fly ash was replaced by highly reactive metakaolin. Two type of fly ashes namely, ASTM class F and ASTM class C were used as a base material for the synthesis of geopolymer mortar. Eight molar sodium hydroxide solution mixed with sodium silicate solution was used as alkaline activator. For optimum geopolymerization, mortar was cured at sixty degree Celsius for twenty four hours duration. Results show different behavior of metakaolin replacement on compressive strength for two different types of fly ash based geopolymer mortar. Improvement in compressive strength was seen by addition of metakaolin in ASTM class F fly ash based geopolymer. On the other hand compressive strength was decreased abruptly in fly ash class C based geopolymer up to certain replacement level.

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.

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%.

scholarly journals Compressive Strength of Fly ash-based Geopolymer Concrete with a Variable of Sodium Hydroxide (NaOH) Solution Molarity

2018 ◽  
Vol 147 ◽  
pp. 01004 ◽  
Author(s):  
Herwani ◽  
Ivindra Pane ◽  
Iswandi Imran ◽  
Bambang Budiono
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Solution Concentration ◽  
Geopolymer Concrete ◽  
Hydroxide Solution ◽  
Naoh Solution ◽  
New Material

Geopolymer concrete is a new material made by activating the raw materials which contain many elements of silica and alumina. Compressive strength of geopolymer concrete produced was influenced by the concentration of the activator solution. This paper presents an experimental investigation into fly ash-based geopolymer concrete. Research objective was to investigate the effects of alkaline activator solution (AAS) molarity on compressive strength of geopolymer concrete. Variable of the test were a solution to sodium hydroxide was chosen as the activator solution. Concentration of sodium hydroxide solution used was 10 M, 12 M and 14 M with ambient curing. The specimen is made of concrete cylinder with diameter 10 cm and height 20 cm as many as 9 pieces each variable. Compressive strength tests is performed when the concrete is 7, 14, and 28 days old. Results of the test are indicated that the increasing of sodium hydroxide (NaOH) solution concentration leads to improve the compressive strength of geopolymer concrete. The optimal compressive strength of geopolymer concrete was achieved at a concentration of sodium hydroxide solution (NaOH) of 12 M. Geopolymer concretes compressive strength only achieves around 50-60% of the planned.

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.

scholarly journals Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

2020 ◽  
Vol 10 (15) ◽  
pp. 5190
Author(s):  
Danutė Vaičiukynienė ◽  
Dalia Nizevičienė ◽  
Aras Kantautas ◽  
Vytautas Bocullo ◽  
Andrius Kielė
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Bottom Ash ◽  
Control Sample ◽  
Test Methods ◽  
X Ray ◽  
Hydroxide Solution ◽  
Fine Grained ◽  
Alkali Activated

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

Effect of Mechanical Activation of Fluidized Bed Fly Ash on Geopolymer Properties

2019 ◽  
Vol 288 ◽  
pp. 51-58
Author(s):  
Gendenjamts Oyun-Erdene ◽  
Jadambaa Temuujin
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Activation ◽  
Sodium Hydroxide ◽  
Fluidized Bed ◽  
Sodium Silicate ◽  
Sodium Hydroxide Solution ◽  
Chemical Activation ◽  
Weight Ratio ◽  
Particle Size Reduction

This paper is focused on the elucidation of mechanical activation effect of circulating fluidized bed combustion fly ash (Amgalan Thermal Station, Mongolia) on mechanical properties of geopolymers. Fluidized bed fly ash was mechanically activated for 15-120 minutes with a vibratory mill. The effect of mechanical activation was quite visible on the particle size reduction and on the degree of amorphization.Geopolymer samples were prepared from the raw and milled fluidized bed fly ashes by alkaline activation. Chemical activation was performed with 10M sodium hydroxide solution, as well as solutions containing a mixture of sodium silicate and sodium hydroxide with a weight ratio of 2:1. The geopolymer cubic specimens were cured at 70°C for 24 hrs and their 7 days uniaxial compressive strength was measured. After curing and drying, the bulk density, water absorption and apparent porosity of geopolymer samples were evaluated.X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetry-differential thermal analysis (TGA-DTA) have been used for the structural characterization of the CFA and the resulting geopolymers. The highest compressive strength of 32.4 MPa was achieved for the fly ash milled for 30 minutes and activated with the solution containing the sodium silicate and 10M sodium hydroxide at a weight ratio of 2:1. Non-milled CFA based geopolymers showed the compressive strength of 16.2 MPa after activation with the same solution. Mechanical activation resulted in an increase in the reactivity of the fluidized bed fly ash and that enhances the geopolymerization reactions.

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