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

2019 ◽  
Vol 296 ◽  
pp. 105-111 ◽  
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.

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.

scholarly journals Study on Setting & Strength Characteristic of GGBS based Geopolymer Concrete by Blending of Fly Ash and Metakaoline

2020 ◽  
Vol 13 (1) ◽  
pp. 117-122
Author(s):  
Addepalli Mallinadh Kashyap ◽  
Tanimki Chandra Sekhar Rao ◽  
N.V. Ramana Rao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Setting Time ◽  
Engineering Properties ◽  
Geopolymer Concrete ◽  
Conventional Concrete ◽  
New Material

Carbon dioxide is liberated in huge amounts by the manufacturing of Portland Pozzolana Cement. Normally, conventional concrete is manufactured with Portland cement, which acts as a binder. The production of cement emits CO2 into the atmosphere, which is a green house gas and causes the environmental pollution. Considering this as a serious environmental problem, there is a need to develop sustainable alternatives to Portland cement utilizing the industrial byproducts such as fly ash, ground granulated blast furnace slag and Metakaoline which are pozzolonic in nature. It has been established that fly ash can replace cement partially. In this context, a new material was developed known as ‖Geopolymer‖. In this study, the various parameters on the short term engineering properties of fresh and hardened properties of Geopolymer Mortar were studied. In the present investigation, cement is replaced by geopolymer source material and water is replaced by alkaline activator consisting of Sodium Silicate and Sodium Hydroxide of molarity (12M). The ratio of sodium silicate to sodium hydroxide adopted was 2.5. The test results showed that final setting time decreases as the GGBS content in the mix increases and also increase in compressive strength. Where as in the case of metakaoline, as the content increases, there is a decrease in compressive strength and setting times of the geopolymer concrete.

The Effect of Activators on the Fly Ash-Based Geopolymers

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.

scholarly journals A Machine Learning-Assisted Numerical Predictor for Compressive Strength of Geopolymer Concrete Based on Experimental Data and Sensitivity Analysis

2020 ◽  
Vol 10 (21) ◽  
pp. 7726
Author(s):  
An Thao Huynh ◽  
Quang Dang Nguyen ◽  
Qui Lieu Xuan ◽  
Bryan Magee ◽  
TaeChoong Chung ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Sensitivity Analysis ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Engineering Properties ◽  
Percentage Error ◽  
Geopolymer Concrete ◽  
Statistical Measures

Geopolymer concrete offers a favourable alternative to conventional Portland concrete due to its reduced embodied carbon dioxide (CO2) content. Engineering properties of geopolymer concrete, such as compressive strength, are commonly characterised based on experimental practices requiring large volumes of raw materials, time for sample preparation, and costly equipment. To help address this inefficiency, this study proposes machine learning-assisted numerical methods to predict compressive strength of fly ash-based geopolymer (FAGP) concrete. Methods assessed included artificial neural network (ANN), deep neural network (DNN), and deep residual network (ResNet), based on experimentally collected data. Performance of the proposed approaches were evaluated using various statistical measures including R-squared (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE). Sensitivity analysis was carried out to identify effects of the following six input variables on the compressive strength of FAGP concrete: sodium hydroxide/sodium silicate ratio, fly ash/aggregate ratio, alkali activator/fly ash ratio, concentration of sodium hydroxide, curing time, and temperature. Fly ash/aggregate ratio was found to significantly affect compressive strength of FAGP concrete. Results obtained indicate that the proposed approaches offer reliable methods for FAGP design and optimisation. Of note was ResNet, which demonstrated the highest R2 and lowest RMSE and MAPE values.

Оbtaining of Lightweight Geopolymer Using Ash from Thermal Power Plants

2014 ◽  
Vol 92 ◽  
pp. 68-73
Author(s):  
Yancho Hristov ◽  
Yordan Kostadinov ◽  
Plamen Pashev ◽  
Bogdan Bogdanov
Keyword(s):  
Water Absorption ◽  
Power Plants ◽  
Inorganic Material ◽  
Thermal Power ◽  
Lightweight Aggregate ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Thermal Power Plants ◽  
Geopolymer Concrete ◽  
Partition Walls

A lightweight inorganic polymer is obtained using by ash from thermal power plants and lightweight aggregate from perlite . This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. In addition, porosity and water absorption were determined. Results showed that the lightweight geopolymer blocks with satisfactory strength and density could be made. The 28-day compressive strength of 5.2–13.8 MPa, density of 1075–1345 kg/m3, water absorption of 10–28% and porosity of 15–32% obtained. It can be used as lightweight geopolymer concrete for partition walls.

The Effect of Curing Time on the Properties of Fly Ash-Based Geopolymer Bricks

2012 ◽  
Vol 626 ◽  
pp. 937-941 ◽  
Author(s):  
W.I. Wan Mastura ◽  
H. Kamarudin ◽  
I. Khairul Nizar ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Experimental Work ◽  
Base Material ◽  
Curing Time ◽  
Curing Conditions ◽  
Alkaline Activator

This paper reports the results of an experimental work conducted to investigate the effect of curing conditions on the properties of fly ash-based geopolymer bricks prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the curing time in the range of 1-24 hours respectively. The specimens cured for a period of 24 hours have presented the highest compressive strength for all ratio of fly ash to sand. For increasing curing time improve compressive strength and decreasing water absorption.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document