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

2017 ◽  
Vol 6 (4) ◽  
pp. 163 ◽  
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.

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.

scholarly journals Compressive Strength and Thermal Conductivity of Fly Ash Geopolymer Concrete Incorporated with Lightweight Aggregate, Expanded Clay Aggregate and Foaming Agent

2019 ◽  
Vol 70 (11) ◽  
pp. 4021-4028 ◽  
Author(s):  
Liew Yun Ming ◽  
Andrei Victor Sandu ◽  
Heah Cheng Yong ◽  
Yuyun Tajunnisa ◽  
Siti Fatimah Azzahran ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide Solution ◽  
Density Ratio ◽  
Lightweight Aggregate ◽  
Alkali Activation ◽  
Geopolymer Concrete ◽  
River Sand ◽  
Foaming Agent

This paper investigates the effect of incorporation of lightweight aggregate and foam in the preparation of lightweight aggregate geopolymer concrete (LWAGC) and lightweight aggregate foamed geopolymer concrete (LWAFGC). The geopolymer paste was formed by alkali activation of Class F fly ash in mixture of sodium silicate and sodium hydroxide solution. LWAGC was incorporated with expanded clay lightweight aggregate and river sand while hydrogen peroxide was added as foaming agent for LWAFGC. Results showed that LWAGC and LWAFGC achieved an excellent 28-day compressive strength of 60 MPa and 20 MPa, respectively. The bulk densities were 1815 kg/m3 for LWAGC and 1593 kg/m3 for LWAFGC. Even so, low thermal conductivity of 0.12 W/mK and 0.09 W/mK were reported. It was concluded that the joint effect of lightweight aggregate and foam produced geopolymer concrete with good mechanical strength while having excellent thermal insulating properties. The geopolymer concretes possessed high strength-to-density ratio to be regarded as lightweight high-performance structures.

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.

Performance of Blended Fly Ash (FA) and Palm Oil Fuel Ash (POFA) Geopolymer Mortar in Acidic Peat Environment

2016 ◽  
Vol 841 ◽  
pp. 83-89 ◽  
Author(s):  
Yudhi Salman Dwi Satya ◽  
Edy Saputra ◽  
Monita Olivia
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Palm Oil ◽  
Alkaline Solution ◽  
Sodium Hydroxide Solution ◽  
Mass Ratio ◽  
Palm Oil Fuel Ash ◽  
Fuel Ash ◽  
Oil Fuel

This paper presents performance of blended geopolymer mortars prepared from fly ash (FA) and palm oil fuel ash (POFA). Both materials are used their Si and Al elements were activated by alkaline solution. The alkaline solution was prepared by mixing sodium silicate and sodium hydroxide. The optimum mix proportion of geopolymer mortar with FA:POFA mass ratio was 90:10. The ratio of sodium silicate solution to sodium hydroxide solution by mass was 2.5:1. The mass ratio of sand to blended ashes was 2.75:1. The mortar specimens were prepared using 5×5×5 cm cube and cured at room temperature (28oC) for 3 days before subsequently heat-cured at 110oC for 24 hours. The specimens were immersed in distilled water and peat water with pH 4-5 for 120 days. The compressive strength change, porosity, and sorptivity tests were taken. In general, the results shows there was a decrease in strength, an increase in porosity and sorptivity of the blended geopolymer mortars. Fourier Transform Infra Red (FTIR) test revealed that interaction of geopolymers mortar with the acidic peat water can also cause replacement of the exchangeable cations (Na, K) in polymers by hidrogen or hydronium ions. Formation of some new zeolitic phases in blended FA-POFA geopolymer mortar exposed to acidic peat water were observed.

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.

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

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.

scholarly journals Development of Alkali Activated Pervious Cementless Concrete

2021 ◽  
Author(s):  
K. Aiswarya ◽  
A. A. Alfiya ◽  
R. Deepak ◽  
V. S. Devadath ◽  
K. P. Ramaswamy
Keyword(s):  
Fly Ash ◽  
Water Absorption ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Sodium Hydroxide Solution ◽  
Pervious Concrete ◽  
Fine Aggregate ◽  
Environment Friendly ◽  
Binder Ratio ◽  
Class F Fly Ash

Pervious concrete is a topic of recent interest and finds vivid applications such as for discharging rain water, filtration of waste water etc. Pervious concrete made with cement as a binder poses serious threats to the environment due to the large amount of green house gases released, especially carbon dioxide, owing to the production of cement. Therefore, it is imperative to find a suitable substitute for cement in the production of concrete. This study presents about the production of pervious concrete, completely replacing cement with fly ash geopolymer binder system. Pervious geopolymer concretes were prepared from Class F fly ash, sodium silicate, sodium hydroxide solution, coarse aggregate and a little quantity of fine aggregate. The alkali to binder ratio of 0.50 by mass and sodium silicate to sodium hydroxide ratio of 2.50 were used. In order to improve the workability of mixture, a super plasticizer Conplast SP 430 (2-3% by weight of binder) was added. Temperature curing at 50 ºC for 24 hours was done. Compression, permeability and water absorption tests were conducted on the specimen at 7 days. The compressive strength of the mixture was found to be 11.66 MPa which is more than that of a brick and water absorption was nearly 2%. The permeability of water through the specimen was found to be 24.63 ml/sec for a pervious cubical specimen of size 10 cm. The pervious concretes produced in this work were not only environment friendly but also achieved better mechanical properties and water permeability. It is inferred that the fly ash geopolymer system could be used to produce pervious concrete.

scholarly journals Compressive Strength and Thermal Conductivity of Fly Ash Geopolymer Concrete Incorporated with Lightweight Aggregate, Expanded Clay Aggregate and Foaming Agent

2019 ◽  
Vol 70 (11) ◽  
pp. 4021-4028
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Lightweight Concrete ◽  
Sodium Hydroxide Solution ◽  
Density Ratio ◽  
Lightweight Aggregate ◽  
Alkali Activation ◽  
Geopolymer Concrete ◽  
Foaming Agent

This paper investigates the effect of incorporation of lightweight aggregate and foam in the preparation of lightweight aggregate geopolymer concrete (LWAGC) and lightweight aggregate foamed geopolymer concrete (LWAFGC). The geopolymer paste was formed by alkali activation of Class F fly ash in mixture of sodium silicate and sodium hydroxide solution. LWAGC was incorporated with expanded clay lightweight aggregate and river sand while hydrogen peroxide was added as foaming agent for LWAFGC. Results showed that LWAGC and LWAFGC achieved an excellent 28-day compressive strength of 60 MPa and 20 MPa, respectively. The bulk densities were 1815 kg/m3 for LWAGC and 1593 kg/m3 for LWAFGC. Even so, low thermal conductivity of 0.12 W/mK and 0.09 W/mK were reported. It was concluded that the joint effect of lightweight aggregate and foam produced geopolymer concrete with good mechanical strength while having excellent thermal insulating properties. The geopolymer concretes possessed high strength-to-density ratio to be regarded as lightweight high-performance structures. Keywords: Lightweight Concrete; Geopolymer; Expanded Clay Aggregate; Foam

scholarly journals Compressive Strength of Geopolymer Concrete Composites: Modeling and Comprehensive Systematic Review

2021 ◽  
Author(s):  
Hemn Unis Ahmed ◽  
Azad A. Mohammed ◽  
Ahmed S. Mohammed
Keyword(s):  
Systematic Review ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Construction Material ◽  
Assessment Tools ◽  
Curing Temperature ◽  
Geopolymer Concrete

Abstract The growing concern about global climate change and its adverse impacts on societies is putting severe pressure on the construction industry as one of the largest producers of greenhouse gases. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is cementless concrete that uses industrial or agro by-product ashes as the main binder instead of ordinary Portland cement; this leads to being an eco-efficient and environmentally friendly construction material. Compressive strength is one of the most important mechanical property for all types of concrete composites including geopolymer concrete, and it is affected by several parameters like an alkaline solution to binder ratio (l/b), fly ash (FA) content, SiO2/Al2O3 (Si/Al) of the FA, fine aggregate (F) and coarse aggregate (C) content, sodium hydroxide (SH) and sodium silicate (SS) content, ratio of sodium silicate to sodium hydroxide (SS/SH), molarity (M), curing temperature (T), curing duration (CD) inside the oven and specimen ages (A). In this regard, a comprehensive systematic review was carried out to show the effect of these different parameters on the compressive strength of the fly ash-based geopolymer concrete (FA-GPC). In addition, multi-scale models such as Artificial Neural Network (ANN), M5P-tree (M5P), Linear Regression (LR), and Multi-logistic Regression (MLR) models were developed to predict the compressive strength of FA-GPC composites. For the first time, in the modeling process, twelve effective parameters including l/b, FA, Si/Al, F, C, SH, SS, SS/SH, M, T, CD, and A were considered the modeling input parameters. Then, the efficiency of the developed models was assessed by various statistical assessment tools like Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Scatter Index (SI), OBJ value, and the Coefficient of determination (R2). Results show that the curing temperature, sodium silicate content, and ratio of the alkaline solution to the binder content are the most significant independent parameters that influence on the compressive strength of the FA-GPC, and the ANN model has better performance for predicting the compressive strength of FA-GPC in compared to the other developed models.

Parametric study of flyash based geopolymer concrete

2018 ◽  
Vol 7 (2.31) ◽  
pp. 196
Author(s):  
Sourav Kumar Das
Keyword(s):  
Fly Ash ◽  
Ambient Temperature ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Power Plants ◽  
Base Material ◽  
Alkali Solution ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
In Situ Conditions

With the growth of civilization the demand of cement concrete is increasing rapidly which increase the production of cement and abolishing the natural source of limestone. Also contributing a lot to the global warming by generating huge amount of carbon-di-oxide. Therefore the present study concentrate on the production of concrete using the geopolymerization technology which replaces cement fully by fly ash, a waste material and alkali solution. India is presently producing approximately 190 million tons of fly ash every year from moreover 145 power plants. Present research is focused on the different parameters which are curing temperature, ratio of sodium silicate to sodium hydroxide, molarity of sodium hydroxide, curing type and the results have been studied and discussed. Previous works emphasis that only the use of fly ash as the base material confine the concrete to be heat cured which limits the applicability of geopolymer concrete to cast-in-situ conditions. So some proportion of flyash is replaced by ground granulated blast furnace slag (GGBFS) and the effect on compressive and tensile strength is observed. Ambient temperature dry curing was done without any water when some proportion of fly ash was replaced by GGBFS. The ratio of sodium silicate solution to sodium hydroxide solution by mass was kept fixed at 2.5 and the concentration of sodium hydroxide was kept 14M. The ratio of flyash to alkali solution was kept 0.35 & 0.40. Replacing 40% of Flyash by GGBFS and keeping the concentration of NaOH as 14M at ambient temperature, the compressive strength encountered was 40 MPa. 

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