Characterization of Effloresences of Ambient and Elevated Temperature Cured Fly Ash Based Geopolymer Type Concretes

Efflorescences formed on the surface of air (ambient) and elevated (70°C) temperatures cured high calcium fly ash based geopolymer type concretes have been characterized by the XRD, SEM-EDX and FTIR techniques. The mineralogical composition of the efflorescence depends on curing temperature. At ambient temperature the main phase of efflorescence consists of atmospheric carbonation product of sodium hydroxide such as thermonatrite (Na2(CO3)·H2O, PDF 8--448), while in the 70°C cured concrete it represents sodium calcium carbonates gaylussite (Na2Ca (CO3)2·5H2O, PDF 21-343). Mineralogical composition difference between the ambient and 70°C cured concrete’s efflolorescences is related to chemical reaction of alkaline liquid with fly ash constituents.

Download Full-text

Characterization of pore solutions expressed from high-calcium fly-ash–water pastes

Fuel ◽

10.1016/s0016-2361(00)00160-5 ◽

2001 ◽

Vol 80 (6) ◽

pp. 815-819 ◽

Cited By ~ 18

Author(s):

J.K. Tishmack ◽

J. Olek ◽

S. Diamond ◽

S. Sahu

Keyword(s):

Fly Ash ◽

High Calcium ◽

High Calcium Fly Ash

Download Full-text

Characterization of the high-calcium fly ash geopolymer mortar with hot-weather curing systems for sustainable application

Advanced Powder Technology ◽

10.1016/j.apt.2017.06.013 ◽

2017 ◽

Vol 28 (9) ◽

pp. 2317-2324 ◽

Cited By ~ 21

Author(s):

Prinya Chindaprasirt ◽

Ubolluk Rattanasak

Keyword(s):

Fly Ash ◽

High Calcium ◽

High Calcium Fly Ash ◽

Hot Weather ◽

Curing Systems

Download Full-text

The effect of adding nano-SiO2 and nano-Al2O3 on properties of high calcium fly ash geopolymer cured at ambient temperature

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2013.09.049 ◽

2014 ◽

Vol 55 ◽

pp. 58-65 ◽

Cited By ~ 169

Author(s):

Tanakorn Phoo-ngernkham ◽

Prinya Chindaprasirt ◽

Vanchai Sata ◽

Sakonwan Hanjitsuwan ◽

Shigemitsu Hatanaka

Keyword(s):

Fly Ash ◽

Ambient Temperature ◽

Nano Sio2 ◽

High Calcium ◽

High Calcium Fly Ash

Download Full-text

Effect of Silica to Alumina Ratio on the Compressive Strength of Class C Fly Ash-Based Geopolymers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.659.80 ◽

2015 ◽

Vol 659 ◽

pp. 80-84 ◽

Cited By ~ 8

Author(s):

Patthamaporn Timakul ◽

Kanyarat Thanaphatwetphisit ◽

Pavadee Aungkavattana

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Curing Temperature ◽

Infrared Study ◽

Xrd Study ◽

High Calcium ◽

High Calcium Fly Ash ◽

Solid Part ◽

Class C ◽

Mae Moh

This study investigated the effect of silica to alumina ratio on the compressive strength of geopolymer. The high calcium fly ash (Class C, ASTM 618) wastes from Mae Moh Thailand power plant, which is SiO2 (30.97%) and Al2O3 (17.16%)-rich materials was employed as the main solid part to prepare geopolymers, apart from kaolinite. The combination of sodium hydroxide (NaOH), sodium silicate (Na2SiO3) solution, and distilled water as 1:1:4 mass ratios were used as the liquid activator. The curing temperature in the oven was fixed at 75oC and varied curing time for 24, 48, 72 and 96 hours. Further curing was done at room temperature for 28 days before characterizations. XRD study of synthesized geopolymers showed a hump of not well-defined peaks and some major peaks of quartz, and unreacted kaolinite indicating the incomplete geopolymerization reaction. Infrared study showed the Al-O-Si and Si-O-Si bonds in all geopolymers samples. The compressive strength of geopolymer increased from 32 to 40 MPa when the ratio of SiO2 : Al2O3 was increased from 2.60 to 2.65. However, the compressive strength was decreased after increasing the SiO2 : Al2O3 ratio from 2.65 to 3.0. The highest compressive strength was found when the SiO2 : Al2O3 ratio was 2.65 with the curing condition at 75oC for 96 h which the samples also possessed high density.

Download Full-text

Characterization of Ferrospheres Recovered from High-Calcium Fly Ash

Energy & Fuels ◽

10.1021/acs.energyfuels.5b01618 ◽

2015 ◽

Vol 29 (8) ◽

pp. 5404-5414 ◽

Cited By ~ 10

Author(s):

Olga M. Sharonova ◽

Natalia N. Anshits ◽

Marina A. Fedorchak ◽

Anatoly M. Zhizhaev ◽

Alexander G. Anshits

Keyword(s):

Fly Ash ◽

High Calcium ◽

High Calcium Fly Ash

Download Full-text

Effects of Temperature in Different Initial Duration Time for Soft Clay Stabilized by Fly Ash Based Geopolymer

Civil Engineering Journal ◽

10.28991/cej-03091141 ◽

2018 ◽

Vol 4 (9) ◽

pp. 2082 ◽

Cited By ~ 2

Author(s):

Abdalla Mohammed Shihab ◽

Jasim M Abbas ◽

Amer M Ibrahim

Keyword(s):

Fly Ash ◽

Low Cost ◽

Soft Clay ◽

Volumetric Strain ◽

Curing Temperature ◽

X Ray Diffraction ◽

Duration Time ◽

High Calcium ◽

High Calcium Fly Ash ◽

Edx Analyses

When soft clay soils are included in engineering projects, it’s stabilized usually with some kinds of admixtures named as stabilizers. The common stabilizers that highly practiced are OPC, lime, high calcium fly ash (FA), etc. Each one of these stabilizers has its shortcomings. Geopolymers are the product of alkali activated aluminosilicate sources that excelled as an alternative to ordinary binders due to its sustainability, low cost and good mechanical properties. This study investigates the effects of some key elements like liquid over fly ash ratio (Liq/FA), initial duration curing time (D) and its temperature to soil – FA based Geopolymers samples characterized by its unconfined compressive strength testing (UCS), volumetric measurements, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-Ray diffraction (XRD). The Liq/FA taken as 2.71, 3.167, 3.8 and 4.75 respectively and the duration time taken were 1, 6, 18 and 24 hrs. respectively. The tests results showed that the maximum peak strength gain when Liq/FA is 3.8 at 90 oC with 24 hrs. D. It was observed that Young’s Modulus increased with increasing curing temperature for certain D. Volumetric strain increased by increasing D and its temperature. SEM and XRD analyses confirmed the Geopolymers gels formation for a selective precursor while EDX analyses showed that silicon over aluminium ratio is 1.38 for selective spectrum within the gel to the same mixture.

Download Full-text