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.

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.

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.

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.

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.

scholarly journals Geopolymer Mortar Incorporating High Calcium Fly Ash and Silica Fume

2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Silica Fume ◽  
Sodium Hydroxide Solution ◽  
Test Results ◽  
Dense Microstructure ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Binder Ratio

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.

scholarly journals Systematic multiscale models to predict the compressive strength of fly ash-based geopolymer concrete at various mixture proportions and curing regimes

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253006
Author(s):  
Hemn Unis Ahmed ◽  
Ahmed Salih Mohammed ◽  
Azad A. Mohammed ◽  
Rabar H. Faraj
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Silicate ◽  
Mean Squared Error ◽  
Curing Temperature ◽  
Coefficient Of Determination ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Palm Oil Fuel Ash ◽  
Binder Ratio

Geopolymer concrete is an inorganic concrete that uses industrial or agro by-product ashes as the main binder instead of ordinary Portland cement; this leads to the geopolymer concrete being an eco-efficient and environmentally friendly construction material. A variety of ashes used as the binder in geopolymer concrete such as fly ash, ground granulated blast furnace slag, rice husk ash, metakaolin ash, and Palm oil fuel ash, fly ash was commonly consumed to prepare geopolymer concrete composites. The most important mechanical property for all types of concrete composites, including geopolymer concrete, is the compressive strength. However, in the structural design and construction field, the compressive strength of the concrete at 28 days is essential. Therefore, achieving an authoritative model for predicting the compressive strength of geopolymer concrete is necessary regarding saving time, energy, and cost-effectiveness. It gives guidance regarding scheduling the construction process and removal of formworks. In this study, Linear (LR), Non-Linear (NLR), and Multi-logistic (MLR) regression models were used to develop the predictive models for estimating the compressive strength of fly ash-based geopolymer concrete (FA-GPC). In this regard, a comprehensive dataset consists of 510 samples were collected in several academic research studies and analyzed to develop the models. In the modeling process, for the first time, twelve effective variable parameters on the compressive strength of the FA-GPC, including SiO2/Al2O3 (Si/Al) of fly ash binder, alkaline liquid to binder ratio (l/b), fly ash (FA) content, fine aggregate (F) content, coarse aggregate (C) content, sodium hydroxide (SH)content, sodium silicate (SS) content, (SS/SH), molarity (M), curing temperature (T), curing duration inside ovens (CD) and specimen ages (A) were considered as the modeling input parameters. Various statistical assessments such as Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Scatter Index (SI), OBJ value, and the Coefficient of determination (R2) were used to evaluate the efficiency of the developed models. The results indicated that the NLR model performed better for predicting the compressive strength of FA-GPC mixtures compared to the other models. Moreover, the sensitivity analysis demonstrated that the curing temperature, alkaline liquid to binder ratio, and sodium silicate content are the most affecting parameter for estimating the compressive strength of the FA-GPC.

Preparation and Characterization of Functional Geopolymer

2008 ◽  
Vol 47-50 ◽  
pp. 977-979
Author(s):  
Yi He Zhang ◽  
Jing Xing ◽  
Li Yu ◽  
Jin Hong Li
Keyword(s):  
Fly Ash ◽  
Glass Fiber ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Quartz Sand ◽  
Sodium Hydroxide Solution ◽  
Liquid Sodium ◽  
Hydroxide Solution ◽  
Structural Template

The geopolymer has been prepared from fly ash, metakaolin and Quartz sand, by using the liquid sodium silicate as structural template and sodium hydroxide solution as activator. The effect of glass fiber on the properties of the geopolymer has been studied.

scholarly journals Development of Sustainable Eco-friendly Geopolymer Composites for Construction Applications

2020 ◽  
Author(s):  
Mohamed Rabie ◽  
Mohammad Irshidat ◽  
Nasser Al-Nuaimi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Power Plants ◽  
Sodium Hydroxide Solution ◽  
Testing Machine ◽  
Heat Curing ◽  
Alkali Solutions ◽  
Binder Ratio ◽  
Class F Fly Ash ◽  
Class F

Geopolymerization is a process where silica and alumina rich source materials turns into excellent binding materials by the aid of alkali solutions. Materials such as fly ash are by-products in energy power plants. Fly ash is classified based on its constituent materials. Fly ash class F mainly consists of alumina and silica. Compressive strength of class F fly ash geopolymer mortar is influenced by many factors such as the molarity of sodium hydroxide solution, fluid to binder ratio, Na2SiO3/NaOH ratio, curing duration and curing temperatures. The present study investigates the effect of these factors on the compressive strength of geopolymer mortar. For each combination, three cubes with dimensions of 50 x 50 x 50 mm were casted. After heat curing in the laboratory oven, the samples were tested on a universal testing machine for the compressive strength. The results showed very high early compressive strength of 63.9 MPa for samples cured at 80 °C and for a duration of 24 hr.

scholarly journals Compressive Strength of Sustainable Geopolymer Concrete Composites: A State-of-the-Art Review

2021 ◽  
Vol 13 (24) ◽  
pp. 13502
Author(s):  
Hemn Unis Ahmed ◽  
Azad A. Mohammed ◽  
Serwan Rafiq ◽  
Ahmed S. Mohammed ◽  
Amir Mosavi ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Construction Material ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
Palm Oil Fuel Ash ◽  
Silicate Content ◽  
Binder Ratio

The building industry, which emits a significant quantity of greenhouse gases, is under tremendous pressure due to global climate change and its consequences for communities. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is an eco-friendly construction material that uses industrial or agricultural by-product ashes as the principal binder instead of Portland cement. Fly ash, ground granulated blast furnace slag, rice husk ash, metakaolin, and palm oil fuel ash were all employed as binders in geopolymer concrete, with fly ash being the most frequent. The most important engineering property for all types of concrete composites, including geopolymer concrete, is the compressive strength. It is influenced by different parameters such as the chemical composition of the binder materials, alkaline liquid to binder ratio, extra water content, superplasticizers dosages, binder content, fine and coarse aggregate content, sodium hydroxide and sodium silicate content, the ratio of sodium silicate to sodium hydroxide, the concentration of sodium hydroxide (molarity), curing temperature, curing durations inside oven, and specimen ages. In order to demonstrate the effects of these varied parameters on the compressive strength of the fly ash-based geopolymer concrete, a comprehensive dataset of 800 samples was gathered and analyzed. According to the findings, the curing temperature, sodium silicate content, and alkaline solution to binder ratio are the most significant independent parameters influencing the compressive strength of the fly ash-based geopolymer concrete (FA-BGPC) composites.

scholarly journals The Effects of Water to Solid Ratio, Activator to Binder Ratio, and Lime Proportion on the Compressive Strength of Ambient-Cured Geopolymer Concrete

2019 ◽  
Vol 5 (2) ◽  
pp. 161 ◽  
Author(s):  
Andi Arham Adam
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide Solution ◽  
Geopolymer Concrete ◽  
Solid Ratio ◽  
Slaked Lime ◽  
Binder Ratio ◽  
Class F Fly Ash ◽  
Good Workability ◽  
Class F

Low calcium fly ash based Geopolymer has been proven to be one of the potential alternatives substitutes to Portland Cement not only due to its high resistance to chemical attack but also because of the vast availability of class F fly ash for raw materials. However, one of the limitations of geopolymer as the alternative binders in concrete is that the strength develops slowly under ambient condition. This paper presented the investigation of water to solid ratio, activator to binder ratio, and lime proportion on the compressive strength of ambient-cured geopolymer concrete. To develop sufficient strength at an early age, class F fly ash and slaked lime (Ca (OH)2) were used as the binder with the proportion of lime to binder of 4%, 5%, 6%, and 7%. The blended binder was activated by sodium silicate and sodium hydroxide solution with the variation of activator to binder ratio of 0.45, 0.5, 0.55, and 0.6.  The water to solid ratio of 0.30, 0.31, 0.32, and 0.33 was chosen to facilitate good workability which was done by adding water to the mix. The compressive strength tests were conducted at 7, 14, and 28 days on the cylindrical concrete specimens with a dimension of 100 mm diameter and 200 mm height. The results show that the activator to binder ratio of 0.50 to 0.55, and the proportion of lime to the binder of 6% to 7% were the optimum range value. It was also found that the lower the water to cement ratio the higher the compressive strength and the water to solid ratio as low as 0.3 produced the highest compressive strength while still maintaining good workability.

Sign in / Sign up

Export Citation Format

Share Document