Effect of sodium hydroxide concentration on chloride penetration and steel corrosion of fly ash-based geopolymer concrete under marine site

Geopolymer concrete (GPC) has drawn widespread attention as a universally accepted ideal green material to improve environmental conditions in recent years. The present study systematically quantifies and compares the environmental impact of fly ash GPC and ordinary Portland cement (OPC) concrete under different strength grades by conducting life cycle assessment (LCA). The alkali activator solution to fly ash ratio (S/F), sodium hydroxide concentration (CNaOH), and sodium silicate to sodium hydroxide ratio (SS/SH) were further used as three key parameters to consider their sensitivity to strength and CO2 emissions. The correlation and influence rules were analyzed by Multivariate Analysis of Variance (MANOVA) and Gray Relational Analysis (GRA). The results indicated that the CO2 emission of GPC can be reduced by 62.73%, and the correlation between CO2 emission and compressive strength is not significant for GPC. The degree of influence of the three factors on the compressive strength is CNaOH (66.5%) > SS/SH (20.7%) > S/F (9%) and on CO2 emissions is S/F (87.2%) > SS/SH (10.3%) > CNaOH (2.4%). Fly ash GPC effectively controls the environmental deterioration without compromising its compressive strength; in fact, it even in favor.

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Effect of sodium hydroxide concentration on the compressive strength of geopolymer mortar using fly ash PLTU Tanjungjati B Jepara

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/955/1/012010 ◽

2022 ◽

Vol 955 (1) ◽

pp. 012010

Author(s):

A Kustirini ◽

Antonius ◽

P Setiyawan

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Coal Industry ◽

Waste Materials ◽

Geopolymer Concrete ◽

Sodium Hydroxide Concentration ◽

Alkaline Activator ◽

Maximum Compressive Strength

Abstract Geopolymer concrete is concrete that uses environmentally friendly materials, using fly ash from waste materials from the coal industry as a substitute for cement. To produce geopolymer concrete, an alkaline activator is required, with a mixture of Sodium Hydroxide and Sodium Silicate. This research is an experimental study to determine the effect of variations in the concentration of sodium hydroxide (NaOH) 8 Mol, 10 Mol, 12 Mol, and 14 Mol on the compressive strength of geopolymer concrete. Mortar Geopolymer uses a mixture of 1: 3 for the ratio of fly ash and sand, 2.5: 0.45 for the ratio of sodium silicate and sodium hydroxide as an alkaline solution. The specimens used a cube mold having dimension 5 cm x 5 cm x 5 cm, then tested at 7 days and 28 days. The test resulted that concentration of NaOH 12 Mol obtained the maximum compressive strength of geopolymer concrete, that is 38.54 MPa. At concentrations of 12 Mol NaOH and exceeding 12M, the compressive strength of geopolymer concrete decreased.

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

Applied Sciences ◽

10.3390/app10217726 ◽

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.

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Artificial Intelligence Approaches for Prediction of Compressive Strength of Geopolymer Concrete

Materials ◽

10.3390/ma12060983 ◽

2019 ◽

Vol 12 (6) ◽

pp. 983 ◽

Cited By ~ 48

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.

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Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

Advances in Materials Science and Engineering ◽

10.1155/2015/731056 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 10

Author(s):

Ganesan Lavanya ◽

Josephraj Jegan

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Sodium Hydroxide ◽

Ordinary Portland Cement ◽

Geopolymer Concrete ◽

Portland Cement Concrete ◽

Cement Concrete ◽

High Calcium ◽

High Calcium Fly Ash ◽

Ordinary Portland Cement Concrete

This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were150×150×150 mm cubes,100×200 mm cylinders, and100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

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Studies on the modification of fly ash structure with alkaline pre-treatment as a green composite flame retardant filler

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1195/1/012015 ◽

2021 ◽

Vol 1195 (1) ◽

pp. 012015

Author(s):

N A M Radzi ◽

A H Sofian ◽

S S Jamari

Keyword(s):

Fly Ash ◽

Pore Size ◽

Sodium Hydroxide ◽

Sodium Hydroxide Solution ◽

Morphological Structure ◽

Green Composite ◽

Sodium Hydroxide Concentration ◽

Physiochemical Properties ◽

Hydrophobic Polymer ◽

Pre Treatment

Abstract A green composite made up of renewable and recyclable materials has become one of the advanced material’s attractive topics. The smooth fly ash surface used in the green composite for flame retardancy enhancement are hard to bind with hydrophobic polymer. Thus, the surface modification of this filler is needed to increase its surface roughness and pore size to be more compatible with its polymer matrix. In this research study, the alkaline pre-treatment of fly ash has been performed by using sodium hydroxide solution (NaOH) with various concentrations (5 w/w%, 10 w/w%, 15 w/w%, 20 w/w%). For pore size and morphological of the filler’s evaluation, few analyses such as Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), Barret-Joyner-Halenda (BJH) and Brunauer-Emmett-Teller (BET) pore size and volume analysis were conducted. Treated fly ash with 20 w/w% sodium hydroxide concentration gives the better morphological structure in terms of pore diameter, volume, area and high composition of aluminium, silicon with lower calcium and sulphur contents compared to others. Hence, the potential of the physiochemical properties of the green composite produced by using this modified filler will be improved as the adhesiveness of the filler with its matrix increased.

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Mechanical Properties of Geopolymer Concrete with Flyash and Metakaolin

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.a1180.109119 ◽

2019 ◽

Vol 9 (1) ◽

pp. 3863-3868 ◽

Cited By ~ 1

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Sodium Hydroxide ◽

Silica Content ◽

Geopolymer Concrete ◽

Long Term Effects ◽

Concrete Production ◽

High Silica ◽

By Products

Trials has been made to produce efficient GPC which gives maximum strength. By-Products from industries such as Fly-Ash, Metakaolin and GGBS can be used in concrete replacement which in-turn reduces carbon-di-oxide (CO2 ) emission affecting to green house. Using the above said products also leads to reduction of water demand in concrete and also shows comparatively no effects on long term effects in concrete, these by-products can effectively be used in concrete production. The high silica content in Fly-Ash and Metakaolin increases the bonding in concrete which in-turn increases the mechanical properties of concrete. Geopolymer concrete of M50 grade was proposed to be produced using fly-ash and Metakaolin instead of cement.Alklai solutions Sodium Hydroxide (NaOH), Sodium Silicate (Na2SiO3) were replaced with water for better bonding and mixing. Molarity of Sodium Hydroxide with 10M and 12M was considered for this study. Ratio of Alkaline solution were considered as 1:2,1:2.5&1:3 to determine the optimum ratio which gives effective strength. In this experimental study, tests were carried on concrete specimens with percentage replacement of Fly-Ash with Buff Metakaolin in variable percentages of 20,40,60,80&100. Mechanical properties of concrete specimens were studied and were compared with control mix results.

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Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska ◽

10.22630/pniks.2021.30.3.39 ◽

2021 ◽

Vol 30 (3) ◽

pp. 464-476

Author(s):

Haider Owaid ◽

Haider Al-Baghdadi ◽

Muna Al-Rubaye

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Sodium Hydroxide ◽

Wood Ash ◽

Splitting Tensile Strength ◽

Waste Paper ◽

Geopolymer Concrete

Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.

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Characteristics of Blended Geopolymer Concrete Using Ultrafine Ground Granulated Blast Furnace Slag and Copper Slag

Annales de Chimie Science des Matériaux ◽

10.18280/acsm.440610 ◽

2020 ◽

Vol 44 (6) ◽

pp. 433-439

Author(s):

Vijayasarathy Rathanasalam ◽

Jayabalan Perumalsami ◽

Karthikeyan Jayakumar

Keyword(s):

Blast Furnace ◽

Fly Ash ◽

Sodium Hydroxide ◽

Blast Furnace Slag ◽

Copper Slag ◽

Fine Aggregate ◽

Geopolymer Concrete ◽

Strength Performance ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS), along with the copper slag (CPS) as replacement of fine aggregate (crushed stone sand). Various parameters considered in this study include different sodium hydroxide concentrations (10M, 12M and 14M); 0.35 as alkaline liquid to binder ratio; 2.5 as sodium silicate to sodium hydroxide ratio and cured in ambient curing condition. Further, geopolymer concrete was manufactured using fly ash as the prime source material which is replaced with UFGGBFS (0%, 5%, 10% and 15%). Copper slag has been used as replacement of fine aggregate in this study. Properties of the fresh manufactured geopolymer concrete were studied by slump test. Compressive strength of the manufactured geopolymer concrete was tested and recorded after curing for 3, 7 and 28 days. Microstructure Characterization of Geopolymer concrete specimens was done by Scanning Electron Microscope (SEM) analysis. Experimental results revealed that the addition of UFGGBFS resulted in an increased strength performance of geopolymer concrete. Also, this study demonstrated that the strength of geopolymer concrete increased with an increase in sodium hydroxide concentration. SEM results revealed that the addition of UFGGBFS resulted in a dense structure.

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A study on the strength development of geopolymer concrete using fly ash

International Journal of Engineering & Technology ◽

10.14419/ijet.v6i4.7761 ◽

2017 ◽

Vol 6 (4) ◽

pp. 163 ◽

Cited By ~ 2

Author(s):

Ramesh Babu Chokkalingam ◽

Ganesan N

Keyword(s):

Fly Ash ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Sodium Hydroxide Solution ◽

Fine Sand ◽

Strength Development ◽

Alkali Activation ◽

Geopolymer Concrete ◽

Water Contaminants ◽

Significant Difference

Cement consumption is increasing day by day due to the tremendous development in the infrastructure facilities. The production of one ton of cement emits approximately one ton of carbon dioxide to the atmosphere. In order to reduce the use of cement a new-generation concrete has been developed such as geopolymer concrete (GPC).Geopolymer Geopolymer is a new material which has the potential to replace ordinary Portland cement. It is an inorganic material synthesized by alkali activation of amorphous aluminosilicates at ambient or slightly increased temperatures having an amorphous to semi-crystalline polymeric structure. In this study, low calcium flyash from Tuticorin was used to produce geopolymer concrete. The geopolymer was synthesized with sodium silicate and sodium hydroxide solutions. The sodium hydroxide pellets was dissolved in the distilled water to make free from mixing water contaminants. The ratio of sodium silicate and sodium hydroxide ratio was kept as 2.5. The concentration of sodium hydroxide solution is 12 Molarity (12M). Other materials used are locally available coarse aggregate and fine sand in surface dry condition. A polycarboxlate HRWRA La Hypercrete S25was used. Cubes of size 100mm were cast for six mix proportions of 450kg/m3 flyash+0.35W/B, 500 kg/m3 flyash+0.35W/B, 550kg/m3 flyash+0.35W/B, 450kg/m3 flyash+.0.40 W/B, 500kg/m3 fly ash+0.40W/B and 550kg/m3 flyash+0.40W/B. The specimens after casting in moulds were kept in oven at 60°C for 6 hours and left to air dry at room temperature and tested at 7 and 28 days. The test results revealed the compressive strength of 30 Mpa was achieved. There was not much significant difference in strength development at 28 days between the mixes due to the increase of flyash content. The microstructural images at 28 days revealed that there was not much difference in the microstructure due to the variation in flyash content from 450 kg/m3 to 550 kg/m3.

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