scholarly journals Effect of various parameters on the workability and strength properties of geopolymer concrete

2021 ◽  
Vol 309 ◽  
pp. 01102
Author(s):  
Nutakki Sai Ketana ◽  
V Srinivasa Reddy ◽  
M V Seshagiri Rao ◽  
S Shrihari
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Strength Properties ◽  
Ash Content ◽  
Geopolymer Concrete ◽  
Alkaline Activator ◽  
Class C ◽  
Class F

In the present study, effect of various molarities of NaOH, various fly ash content and alkaline activator solution (AAS) / fly ash(FA) ratios on the workability of geopolymer concrete(GPC) are studied along with the effect of use of Na2SiO3/NaOH and K2SiO3/KOH as alkaline activator solutions and various fly ash contents on the compressive strength of geopolymer concrete mixes. Observations shows that both Na2SiO3/NaOH and K2SiO3/KOH gives better performance for different molar, AAS/FA and oxide ratios. Class C GPC has better performance than Class F GPC. It was found that the increase in molarity decreases workability of geopolymer concrete. Also, the workability increases with increase in fly ash (FA) content and AAS/FA ratio in geopolymer concrete. Compressive and split tensile strengths decrease with increase in fly ash content.

scholarly journals Effect of molarity of sodium hydroxide and molar ratio of alkaline activator solution on the strength development of geopolymer concrete

2021 ◽  
Vol 309 ◽  
pp. 01058
Author(s):  
V Srinivasa Reddy ◽  
Karnati Vamsi Krishna ◽  
M V Seshagiri Rao ◽  
S Shrihari
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Ash Content ◽  
Mix Design ◽  
Molar Ratio ◽  
Strength Development ◽  
Geopolymer Concrete ◽  
Synergic Effect ◽  
Alkaline Activator

In the current study, effect of SiO2/Na2O ratio in Sodium silicate (Na2SiO3) solution, Na2SiO3/NaOH ratio and molarity of NaOH on the compressive strength of geopolymer concrete. A geopolymer mix design is formulated with various mixes are casted with alkali activator solution (AAS) / fly ash (FA) =0.5 and constant fly ash content. The molar ratio of SiO2/Na2O in Na2SiO3 solution is altered from 1.50 to 3.00 for different ratios of Na2SiO3/NaOH (2.0, 2.5 and 3.0) and also for various molarities of NaOH (8M,10M,12M,14M,16M and 18M) are studied for their synergic effect on the compressive strength of geopolymer concrete. Results highlighted that the 16M NaOH yields high compressive strength when SiO2/Na2O in Na2SiO3 solution is around 2.00 to 2.40 and Na2SiO3/NaOH=2.5.

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.

scholarly journals Mechanical and Microstructural Characterization of Quarry Rock Dust Incorporated Steel Fiber Reinforced Geopolymer Concrete and Residual Properties after Exposure to Elevated Temperatures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6890
Author(s):  
Muhammad Ibraheem ◽  
Faheem Butt ◽  
Rana Muhammad Waqas ◽  
Khadim Hussain ◽  
Rana Faisal Tufail ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Strength ◽  
Elevated Temperatures ◽  
Strength Properties ◽  
Steel Fibers ◽  
Geopolymer Concrete

The purpose of this research is to study the effects of quarry rock dust (QRD) and steel fibers (SF) inclusion on the fresh, mechanical, and microstructural properties of fly ash (FA) and ground granulated blast furnace slag (SG)-based geopolymer concrete (GPC) exposed to elevated temperatures. Such types of ternary mixes were prepared by blending waste materials from different industries, including QRD, SG, and FA, with alkaline activator solutions. The multiphysical models show that the inclusion of steel fibers and binders can enhance the mechanical properties of GPC. In this study, a total of 18 different mix proportions were designed with different proportions of QRD (0%, 5%, 10%, 15%, and 20%) and steel fibers (0.75% and 1.5%). The slag was replaced by different proportions of QRD in fly ash, and SG-based GPC mixes to study the effect of QRD incorporation. The mechanical properties of specimens, i.e., compressive strength, splitting tensile strength, and flexural strength, were determined by testing cubes, cylinders, and prisms, respectively, at different ages (7, 28, and 56 days). The specimens were also heated up to 800 °C to evaluate the resistance of specimens to elevated temperature in terms of residual compressive strength and weight loss. The test results showed that the mechanical strength of GPC mixes (without steel fibers) increased by 6–11%, with an increase in QRD content up to 15% at the age of 28 days. In contrast, more than 15% of QRD contents resulted in decreasing the mechanical strength properties. Incorporating steel fibers in a fraction of 0.75% by volume increased the compressive, tensile, and flexural strength of GPC mixes by 15%, 23%, and 34%, respectively. However, further addition of steel fibers at 1.5% by volume lowered the mechanical strength properties. The optimal mixture of QRD incorporated FA-SG-based GPC (QFS-GPC) was observed with 15% QRD and 0.75% steel fibers contents considering the performance in workability and mechanical properties. The results also showed that under elevated temperatures up to 800 °C, the weight loss of QFS-GPC specimens persistently increased with a consistent decrease in the residual compressive strength for increasing QRD content and temperature. Furthermore, the microstructure characterization of QRD blended GPC mixes were also carried out by performing scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS).

scholarly journals Workability and Strength Properties of Class C Fly Ash-Based Geopolymer Mortar

2019 ◽  
Vol 258 ◽  
pp. 01009
Author(s):  
Remigildus Cornelis ◽  
Henricus Priyosulistyo ◽  
Iman Satyarno ◽  
Rochmadi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Strength Properties ◽  
Mass Ratio ◽  
Heat Curing ◽  
Absolute Volume ◽  
High Calcium ◽  
Class C ◽  
Direct Tensile ◽  
Ambient Curing

Fly ash-based geopolymer mortar normally achieves expected properties by heat curing. This becomes one of the obstacles for in-situ applications. The development of high calcium fly ash-based geopolymer mortar, suitable for ambient curing, will gain the applicability of such a material in civil structures. This article reports the results of an experimental study on mortar workability and the increasing of compressive strength of class C fly ash-based geopolymer mortar created in ambient curing condition. The main synthesis parameters such as alkali to the cementitious mass ratio varied from 30% to 40% by an increment of 5% and absolute volume of paste to absolute volume of voids of the aggregate ratio varied from 1 to 2 by an increment of 0.25. These parameters were designed to figure out their individual effects on mortar workability and the mechanical properties for the production of geopolymer mortar. The results suggested that the workability of mortar generally increased by using alkali to the cementitious mass ratio. The compressive strength of 60 MPa and the direct tensile strength of 2.8 MPa, the ratio of alkali to the cementitious mass of 0.35 and absolute volume of paste to absolute volume of voids of the aggregate ratio was 1.5; it was obtained at ambient temperature after 28 days of age. The results will be useful for developing the knowledge for the use of class C fly ash in producing geopolymer concrete, which is currently in progress. Hopefully, this contribution of research will improve the applications of such new binding material in the future.

scholarly journals Influence of the Nature and Rate of Alkaline Activator on the Physicochemical Properties of Fly Ash-Based Geopolymers

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Marouane EL Alouani ◽  
Saliha Alehyen ◽  
Mohammed EL Achouri ◽  
Abdelowahed Hajjaji ◽  
Chouaib Ennawaoui ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physicochemical Properties ◽  
Fire Resistance ◽  
Electrical Performance ◽  
Infrared Spectrometry ◽  
X Ray ◽  
Alkaline Activator ◽  
Class F Fly Ash ◽  
Class F

The influence of alkali cations on mix design of geopolymers is essential for their mechanical, thermal, and electrical performance. This research investigated the influence of alkali cation type on microscale characteristics and mechanical, dielectric, and thermal properties of fly ash-based geopolymer matrices. The geopolymers were elaborated via class F fly ash from the thermal plant Jorf Lasfar, El Jadida (Morocco), and several alkaline solutions. Morphological, structural, mechanical, dielectric, and thermal characteristics of materials synthesized via fly ash with different proportions of KOH and NaOH aged 28 days were evaluated. The physicochemical properties of class F fly ash-based geopolymers were assessed using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX) analyses. Based on readings of the results obtained, XRD and FTIR analysis detected the creation of semicrystalline potassium/sodium aluminate-silicate hydrate (KASH/NASH) gel in the elaborated matrices after the geopolymerization reaction. The SEM analysis proved the formation of alkali alumina-silicate hydrate gel in the raw material particles after the polycondensation stage. Experimental compressive strength data indicated that the highest compressive strength (39 MPa) was produced by the alkaline activator (75% KOH/25% NaOH). The dielectric parameters values of the elaborated materials changed depending of the mass ratios KOH/NaOH. Dielectric findings demonstrated that geopolymers containing 100% NaOH have better dielectric performances. The fire resistance study revealed that the geopolymer binders induced by KOH are stable up to 600°C. Based on these results, it can be deduced that the formulated geopolymer concrete possesses good mechanical, dielectric, and fire resistance properties.

scholarly journals A Comparative Study on the Effect of Class C and Class F Fly Ashes on Geotechnical Properties of High-Plasticity Clay

CivilEng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 1009-1018
Author(s):  
Salar Shirkhanloo ◽  
Mohammad Najafi ◽  
Vinayak Kaushal ◽  
Mehrdad Rajabi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Geotechnical Properties ◽  
Dry Density ◽  
High Plasticity ◽  
Fly Ashes ◽  
High Plasticity Clay ◽  
Class C ◽  
Class F

Clays generally have a low strength and capacity, and additives are usually used to stabilize them. In recent years, using fly ash to stabilize soil has decreased environmental pollution while also having an economic benefit. The objective of this study is to perform a comparative investigation on the effect of class C and class F fly ashes on geotechnical properties of high-plasticity clay using the Atterberg’s limit, compaction, California Bearing Ratio (CBR), and unconfined compressive strength tests. The results showed that with an increase in the amount of fly ash, there was a decrease in the maximum dry density and an increase in the optimum moisture content. Moreover, an addition of fly ashes of up to 25% caused a reduction of the liquid limit and plasticity index, and an increase in the maximum unconfined compressive strength and CBR. Lengthening the curing time had a positive impact on the unconfined compressive strength of the soil. The soil samples with class C fly ash were seen to possess more efficient geotechnical properties as compared to class F fly ash.

scholarly journals Efficacy of Class C Fly Ash as a Stabilizer for Marginal Residual Soil

2020 ◽  
Vol 5 (1) ◽  
pp. 97-104
Author(s):  
M Umar ◽  
H. M. Alhassan
Keyword(s):  
Fly Ash ◽  
Road Construction ◽  
Strength Properties ◽  
Ash Content ◽  
Engineering Properties ◽  
Dry Density ◽  
Residual Soil ◽  
Compression Tests ◽  
Two Samples ◽  
Class C

Two laterites samples known for their deficiency in road construction were used to assess the efficacy of Class C fly ash in improving their engineering properties. The two samples were taken from Danbare and Dausayi localities within Kano Metropolis and the fly ash was sourced from the Nigerian Coal Corporation, Enugu. Preliminary tests on the two samples confirmed their deficiency for use in road construction. The processed fly ash was blended with the laterite samples at 0, 3, 6, 9, 12, 15 and 18%. Hence, the treated soil samples were tested for plasticity, compaction and strength properties. Results obtained revealed reduction in plasticity properties as the fly ash contents increased. Similarly, Maximum Dry Density (MDD) decreased as the fly ash content increased while the Optimum Moisture Content (OMC) of the treated soils increased for the two samples. Peak CBR values of 16 and 35% were obtained at 9 and 15% fly ash contents for samples 1 and 2, respectively. The unconfined compression tests showed considerable improvement in strength properties higher than the values of the natural soils. The peak 7 days strength of 630 and 1410 kN/m2 were observed at 12% and 15% fly ash content for samples 1 and 2, respectively.

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 Experimental and Statistical Study on Mechanical Characteristics of Geopolymer Concrete

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1651 ◽  
Author(s):  
Yifei Cui ◽  
Kaikai Gao ◽  
Peng Zhang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Mechanical Characteristics ◽  
Statistical Hypothesis ◽  
Geopolymer Concrete ◽  
Empirical Equations ◽  
Class F Fly Ash ◽  
Class F

This paper studies the statistical correlation in mechanical characteristics of class F fly ash based geopolymer concrete (CFGPC). Experimentally measured values of the compressive strength, elastic modulus and indirect tensile strength of CFGPC specimens made from class F fly ash (CFA) were presented and analyzed. The results were compared with those of corresponding ordinary Portland cement concrete (OPCC) using statistical hypothesis tests. Results illustrated that when possessing similar compressive and tensile strength, the elastic modulus for CFGPC is significantly lower than that of OPCC. The corresponding expressions recommended by standards for the case of OPCC is proved to be inaccurate when applied in the case of CFGPC. Statistical regression was used to identify tendencies and correlations within the mechanical characteristics of CFGPC, as well as the empirical equations for predicting tensile strength and elastic modulus of CFGPC from its compressive strength values. In conclusion, CFGPC and OPCC has significant differences in terms of the correlations between mechanical properties. The empirical equations obtained in this study could provide relatively accurate predictions on the mechanical behavior of CFGPC.

Mechanical Properties of Volcanic Ash Based Geopolymer Concrete

2016 ◽  
Vol 857 ◽  
pp. 377-381 ◽  
Author(s):  
Puput Risdanareni ◽  
Adjib Karjanto ◽  
Januarti Jaya Ekaputri ◽  
Poppy Puspitasari ◽  
Febriano Khakim
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Research And Development ◽  
Volcanic Ash ◽  
Fresh Concrete ◽  
Geopolymer Concrete ◽  
Reconstruction Process ◽  
The World ◽  
Alkaline Activator

This paper presents the result of study on using volcanic ash which obtained from Mount Kelud as fly ash replacement material to produce geopolymer concrete. Test was conducted on geopolymer concrete mixture with 0%, 25%, 50% and 100% fly ash replacement with Kelud volcanic ash. Sodium hydroxide (NaOH) and Sodium Silicate (Na2SiO3) were applied as alkaline activator. The mechanical properties was assessed by compressive strength while workability of fresh concrete by slump test. Producing geopolymer concrete with volcanic ash is possible with maximum replacement of up to 50%. Research and development on eco-friendly material such as volcanic ash is very useful to help reconstruction process of volcanic disaster around the world.

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