Effect of Mixing Procedure and Chemical Composition on Physical and Mechanical Performance of Geopolymers

2021 ◽  
Vol 1017 ◽  
pp. 41-50
Author(s):  
Natalia I. Kozhukhova ◽  
Anastasia Yu. Teslya ◽  
Natalia I. Alfimova ◽  
Marina I. Kozhukhova
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Ambient Temperature ◽  
Alkaline Solution ◽  
Component Composition ◽  
Temperature Treatment ◽  
Curing Temperature ◽  
Temperature Conditions ◽  
Alkaline Activator ◽  
Geopolymer Paste

Nowadays geopolymer is promising and relevant material that can be effectively used in wide range of application areas. It is possible because of there are a lot of potential sources of raw materials for geopolymer synthesis. Raw components are the one of the key parameters that effect on geopolymer performance. On the other hands, the technological stages of geopolymer synthesis is no less important factor. The purpose of this study was to determine effect of technological parameters of geopolymer synthesis such as component composition of solid state phase, alkaline activator preparation and its introduction onto geopolymer paste as well as curing temperature on performance characteristics of geopolymer. Fly-ash based geopolymer samples were prepared with adding of different mineral components: Portland cement (PC), kaolin, metakaolin; different curing temperature conditions: ambient temperature and temperature treatment at 70 °C in oven during 24 hours; different methods of preparation and application of alkaline activator: using of fresh alkaline solution and using alkaline solution after 24 hours of cooling. The results show that efficiency of curing temperature conditions strongly depend on component composition of geopolymer paste. Samples, containing PC and metakaolin demonstrate better characteristics after curing under ambient temperature. Samples, containing kaolin and reference composition (fly ash only) the temperature treatment in oven is the best curing method (increasing in compressive strength up to 13 times). Using alkaline solution of NaOH after 24 hours of cooling gives a good effect on geopolymerization process and provides increasing in compressive strength value from 13 to 84 % for all experimental geopolymer pastes. However, average density for all compositions is varied slightly.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

The Relationship of NaOH Molarity, Na2SiO3/NaOH Ratio, Fly Ash/Alkaline Activator Ratio, and Curing Temperature to the Strength of Fly Ash-Based Geopolymer

2011 ◽  
Vol 328-330 ◽  
pp. 1475-1482 ◽  
Author(s):  
M. M. A. Abdullah ◽  
H. Kamarudin ◽  
M. Bnhussain ◽  
I. Khairul Nizar ◽  
A.R. Rafiza ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Curing Temperature ◽  
Test Results ◽  
Compression Tests ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Relationship Of ◽  
The Relationship

Geopolymer, produced by the reaction of fly ash with an alkaline activator (mixture of Na2SiO3 and NaOH solutions), is an alternative to the use of ordinary Portland cement (OPC) in the construction industry. However, there are salient parameters that affecting the compressive strength of geopolymer. In this research, the effects of various NaOH molarities, Na2SiO3/NaOH ratios, fly ash/alkaline activator, and curing temperature to the strength of geopolymer paste fly ash were studied. Tests were carried out on 50 x 50 x 50 mm cube geopolymer specimens. Compression tests were conducted on the seventh day of testing for all samples. The test results revealed that a 12 M NaOH solution produced the highest compressive strength for the geopolymer. The combination mass ratios of fly ash/alkaline activator and Na2SiO3/NaOH of 2.0 and 2.5, respectively, produced the highest compressive strength after seven days. Geopolymer samples cured at 60 °C produced compressive strength as high as 70 MPa.

scholarly journals CRYSTALLINE PHASE REACTIVITY IN THE SYNTHESIS OF FLY ASH-BASED GEOPOLYMER

2011 ◽  
Vol 11 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Lukman Atmaja ◽  
Hamzah Fansuri ◽  
Anggaria Maharani
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Power Plant ◽  
Ambient Temperature ◽  
Alkaline Solution ◽  
Crystalline Phase ◽  
Rietveld Method ◽  
Initial Reaction ◽  
Crystalline Phases ◽  
Significant Change

Aluminosilicate, alkaline solution and fly ash from a power plant have been used to synthesize geopolymer at ambient temperature. SiO2/Al2O3 mole ratio of the starting materials was varied by the addition of pure, insoluble corundum and quartz. The geopolymer exhibited some differences in the ratio of initial reaction mixtures and that of final products. The corundum gave no influence to the compressive strength while the quartz at SiO2/Al2O3=4.0-6.0 produced significant change in the strength. The highest compressive strength achieved was 65 MPa. XRD using analysis Rietveld method proved that quartz has been found both in starting materials as well as in the geopolymer indicating the involvement of crystalline phases, to some extent, in geopolymerization process.

THE INFLUENCE OF INITIAL MATERIALS ON THE COMPRESSIVE STRENGTH OF GEOPOLYMER SOILS

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Hong Chan Nguyen ◽  
Anh Tuan Nguyen ◽  
Namshik Ahn
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Building Materials ◽  
Clay Content ◽  
Carbon Dioxide Production ◽  
Environmental Benefits ◽  
Curing Temperature ◽  
Low Carbon

In recent years, geopolymers have received significant attention because they show environmental benefits, such as a reduction in the consumption of natural resources and a decrease in the net production of CO2. In addition, as green material, soil has low carbon dioxide production emissions compared to other building materials. In this research, soil was combined with activator alkaline to produce hardening materials as geopolymer soils. An alkaline solution with sodium hydroxide, sodium silicate and fly ash was used. The influence of clay content on the geopolymer soils’ compressive strength was investigated. The best strengths were obtained from 5% to 12% clay content. SEM photos were also taken from specimens to investigate the structure of geopolymer soils. When combined with soil and fly ash in geopolymerization, fly ash reacted to the alkali solution quickly. The relationships between many variables such as clay content, fly ash, alkaline solution, curing time, and curing temperature were investigated by using a statistical analysis program with over 100 initial parameters. These results also indicate that the use of soils in geopolymer soil should have been limited. Additionally, increasing the sodium silicate in the alkaline liquid affected the geopolymerization reaction significantly. However, the suitable Si on the alkaline solution and soil should be limited.

Optimization of Alkaline Activator/Fly ASH Ratio on the Compressive Strength of Manufacturing Fly ASH-BASED Geopolymer

2011 ◽  
Vol 110-116 ◽  
pp. 734-739 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Kamarudin ◽  
Omar A.K.A. Abdulkareem ◽  
Che Mohd Ruzaidi Ghazali ◽  
A.R. Rafiza ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Alkaline Solution ◽  
Room Temperature ◽  
High Strength ◽  
Constant Ratio ◽  
Optimum Amount ◽  
Molar Ratios ◽  
Naoh Solution ◽  
Alkaline Activator

Fly ash and a mixture of alkaline activators namely sodium silicate (Waterglass) and sodium hydroxide (NaOH) solution were used for preparing geopolymer. The aim of this research is to determine the optimum value of the alkaline activator/fly ash ratio. The effect of the oxide molar ratios of SiO2/Al2O3, water content of the alkaline activator and the Waterglass% content were studied for each Alkaline activator/fly ash ratio. The geopolymers were synthesized by the activation of fly ash with alkaline solution at three different alkaline activator/fly ash ratios which were 0.3, 0.35, and 0.4 at a specific constant ratio of waterglass/NaOH solution of 1.00. The geopolymers were cured at 70°C for 24 h and cured to room temperature. Results revealed that the alkaline activator/fly ash ratio of 0.4 has the optimum amount of alkaline liquid, which shows the highest rate of geopolymerization compared to other ratios. A high strength of 8.61 MPa was achieved with 0.4 of activator/fly ash ratio and 14% of waterglass content.

Effect of the Combined Using of Fly Ash and Granulated Blast Furnace Slag on Properties of Cementless Alkali-Activated Mortar

2011 ◽  
Vol 287-290 ◽  
pp. 916-921
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Mixture Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This paper examines the effects of the mixture ratio of fly ash/slag, the type of alkaline activators and curing conditions on the workability, compressive strength and microstructure of cementless alkali-activated mortar. The investigation showed that the mixture ratio of fly ash/slag and the type of alkaline activator have significant influence on the workability and strength, whereas the curing temperature has relatively poor effect. An alkali-activated mortar using a binder composed of 50% of fly ash and 50% of granulated blast furnace slag and alkaline activator made of 9M NaOH and sodium silicate in proportion of 1:1 is seen to be able to develop a compressive strength of 65 MPa at age of 28 days even when cured at ambient temperature of 20°C.

Compressive Strength and Morphology of Fly Ash Based Geopolymer as Artificial Aggregate with Different Curing Temperature

2013 ◽  
Vol 594-595 ◽  
pp. 151-155 ◽  
Author(s):  
Alida Abdullah ◽  
Abdullah Mohd Mustafa Al Bakri ◽  
Hussin Kamarudin ◽  
C.M. Ruzaidi ◽  
Zarina Yahya ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Fly Ash ◽  
Excellent Result ◽  
Curing Temperature ◽  
Mix Design ◽  
Scanning Electron ◽  
Geopolymer Paste

This paper presented the compressive strength of geopolymer paste with different NaOH concentration and morphology analysis for sintered artificial aggregate. This artificial aggregate was produce based on mix design with highest compressive strength which is 12 M. The sample was cured at 70 °C for 24 hours and then it was exposed to different temperature at range 500 °C to 700 °C. Scanning Electron Microscopy (SEM) has been used to identify the formation of microstructure. The geopolymer artificial aggregate was an alternative ways to produce a greener environmental. In this study, the compressive strength for different Na2SiO3/NaOH ratio has been analyzed. The morphology for best mix design then were analyze for different curing temperature. The result shows fly ash based geopolymer paste with 12 M of NaOH concentration shows excellent result with 7.30 MPa at 2.5 ratio of Na2SiO3/NaOH and for geopolymer artificial aggregate, when temperature of heat treatment increased, the open porosity of porous geopolymer surface decreased.

Microstructure Study on Optimization of High Strength Fly Ash Based Geopolymer

2012 ◽  
Vol 476-478 ◽  
pp. 2173-2180 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mohammed Binhussain ◽  
Ismail Khairul Nizar ◽  
Rafiza Abd Razak ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
High Strength ◽  
Curing Temperature ◽  
Mix Design ◽  
Dense Matrix ◽  
Microstructural Characteristics ◽  
Naoh Solution ◽  
Alkaline Activator

The compressive strength and microstructural characteristics of fly ash based geopolymer with alkaline activator solution were investigated. The sodium hydroxide and sodium silicate were mixed together to form an alkaline activator. Three parameters including NaOH molarity, mix design (fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio), and curing temperature were examined. The maximum strength of 71 MPa was obtained when the NaOH solution of 12M, fly ash/alkaline activator of 2.0, Na2SiO3/NaOH of 2.5 and curing temperature of 60°C were used at 7th days of testing. The results of SEM indicated that for geopolymer with highest strength, the structure was dense matrix and contains less unreacted fly ash with alkaline activator

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