The effect of 60Co gamma irradiation on coal fly-ash geopolymer paste setting time

Cementation is the baseline technology for conditioning of low to intermediate level radioactive waste. Geopolymers, a class of alkali activated binders, are a promising new material for radioactive waste treatment. Coal fly-ash based geopolymers are a low-cost, low greenhouse gas footprint alternative to metakaolin based materials. Both the grouting of sludge/powders/liquids and encapsulation of solids/compacted waste rely on the grout maintaining optimal flow (rheological properties) during the mixing and pouring operations, and achieving a set leading to proper long term solidification (mechanical properties). The initial and final setting time for fly-ash geopolymer paste, based on the SRPS EN 196-3 standard, has been measured upon irradiation by gamma rays in a 60Co reference field positioned with a kerma air rate of 3.42 mGys?1. The binder paste was prepared using fly-ash from the TENT B power plant's electrostatic filters without further sieving, activated by water glass with module 1.5 and mixed with distilled water until a satisfactory flow was obtained, and poured into the sample and control molds. The initial and final setting times for the irradiated sample and non-irradiated control were determined by the Vicat apparatus. The irradiated sample demonstrated an 11 % shorter initial setting time, and 16 % shorter final setting time, compared to the control.

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Influence of Triethanolamine on the Properties of Cement-Based Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.2010 ◽

2017 ◽

Vol 898 ◽

pp. 2010-2017 ◽

Cited By ~ 2

Author(s):

Xiao Ying Wang ◽

Ming Zhang Lan ◽

Wei Fang Hou ◽

Bin Feng Xiang ◽

Xu Dong Zhao

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Cement Hydration ◽

Setting Time ◽

Cementitious Materials ◽

Hydration Products ◽

Initial Setting Time ◽

Final Setting Time ◽

Retarding Effect ◽

Initial Setting

The effects of triethanolamine on the compressive strength and setting time of fly ash cementitious materials, slag cementitious materials, and limestone cementitious materials were investigated. The results show that the dosage of 0.04% of triethanolamine can significantly improve the 3d, 7d and 28d compressive strength of fly ash cementitious materials. It possesses less impact on the setting time. The dosage of 0.04% of triethanolamine can significantly improve the 3d and 7d compressive strength of slag cementitious materials while the effect of late strength is not obvious. It extends the initial setting time and the final setting time is not changed, which has retarding effect. The results of hydration heat and XRD show that triethanolamine extends the induction period of cement hydration, and gypsum is exhausted in advance during the hydration process. Triethanolamine promotes the transformation of AFt to AFm and there is no effect on the type of hydration products.

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Final Setting Time and Compressive Strength of Fly Ash and GGBS-Based Geopolymer Paste and Mortar

Arabian Journal for Science and Engineering ◽

10.1007/s13369-015-1757-z ◽

2015 ◽

Vol 40 (11) ◽

pp. 3067-3074 ◽

Cited By ~ 37

Author(s):

G. Mallikarjuna Rao ◽

T. D. Gunneswara Rao

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Setting Time ◽

Final Setting Time ◽

Geopolymer Paste

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A Noble and Economical Method for the Synthesis of Low Cost Zeolites From Coal Fly Ash Waste

Advances in Materials and Processing Technologies ◽

10.1080/2374068x.2021.1927640 ◽

2021 ◽

pp. 1-19

Author(s):

Virendra Kumar Yadav ◽

R Suriyaprabha ◽

Gajendra Kumar Inwati ◽

Nitin Gupta ◽

Bijendra Singh ◽

...

Keyword(s):

Fly Ash ◽

Low Cost ◽

Coal Fly Ash ◽

Economical Method

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Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.629-630.306 ◽

2014 ◽

Vol 629-630 ◽

pp. 306-313 ◽

Cited By ~ 1

Author(s):

Mao Chieh Chi ◽

Ran Huang ◽

Te Hsien Wu ◽

Toun Chun Fou

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Fluidized Bed ◽

Building Materials ◽

Circulating Fluidized Bed ◽

Setting Time ◽

Fluidized Bed Combustion ◽

Initial Setting Time ◽

Cfbc Fly Ash ◽

Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

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Properties of non-standard fly ash – slag cements containing calcareous fly ash

Budownictwo i Architektura ◽

10.35784/bud-arch.2034 ◽

2013 ◽

Vol 12 (3) ◽

pp. 215-222

Author(s):

Katarzyna Synowiec

Keyword(s):

Fly Ash ◽

Blast Furnace Slag ◽

Strength Class ◽

Setting Time ◽

Heat Of Hydration ◽

Initial Setting Time ◽

Granulated Blast Furnace Slag ◽

Unfavorable Effect ◽

Initial Setting ◽

Furnace Slag

The paper presents the tests results of the properties of non - standard fly ash - slag cements composition. Both natural (unprocessed) and activated by grinding calcareous fly ash was used. It was found that the calcareous fly ash next to the granulated blast furnace slag may be a component of low - clinker cements (ca. 40%). Those cements are characterized by low heat of hydration and overdue of initial setting time in comparison with Ordinary Portland Cement, moreover they have an unfavorable effect on consistency and its upkeep in time. Production of fly ash - slag cements is possible for strength class 32,5 N when the component of cement is raw fly ash, and for strength classes 32,5 N, 32,5 R and 42,5 N when ground fly ash was used. Fly ash activated by grinding was characterized by higher activity.

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Synthesis of hydrous iron oxide/aluminum hydroxide composite loaded on coal fly ash as an effective mesoporous and low-cost sorbent for Cr(VI) sorption: Fuzzy logic modeling

Process Safety and Environmental Protection ◽

10.1016/j.psep.2017.02.012 ◽

2017 ◽

Vol 107 ◽

pp. 153-167 ◽

Cited By ~ 14

Author(s):

Seyed Mostafa Hosseini Asl ◽

Mojtaba Masomi ◽

Morteza Hosseini ◽

Hamedreza Javadian ◽

Montserrat Ruiz ◽

...

Keyword(s):

Fuzzy Logic ◽

Iron Oxide ◽

Fly Ash ◽

Aluminum Hydroxide ◽

Low Cost ◽

Coal Fly Ash ◽

Logic Modeling ◽

Fuzzy Logic Modeling ◽

Hydrous Iron Oxide

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Modified coal fly ash as low cost adsorbent for removal reactive dyes from batik industry

MATEC Web of Conferences ◽

10.1051/matecconf/201815401037 ◽

2018 ◽

Vol 154 ◽

pp. 01037 ◽

Cited By ~ 4

Author(s):

Agus Taufiq ◽

Pratikno Hidayat ◽

Arif Hidayat

Keyword(s):

Fly Ash ◽

Low Cost ◽

Coal Fly Ash ◽

Reactive Dyes ◽

Bet Surface Area ◽

Batch Adsorption ◽

Operational Parameters ◽

Solution Ph ◽

Percentage Removal ◽

Modified Fly Ash

The removal of reactive dyes on modified coal fly ash has been investigated during a series of batch adsorption experiments. Physical characteristics of modified coal fly ash was characterized by Brunauer Emmett Teller (BET) surface area analysis, X-ray powder diffraction (XRD), Fourier transform infrared spectrophotometer (FT-IR), and scanning electron microscope (SEM). The effects of operational parameters such as initial dye concentration (50–200 mg/L), solution pH (4–10) and adsorbent dosage (50–200 mg/L) were studied. The adsorption experiments indicated that modified coal fly ash was effective in removing of Remazol Blue. The percentage removal of dyes increased while the modified fly ash dosage increased. The percentage removal of dyes increased with decreased initial concentration of the dye and also increased with amount of adsorbent used. The optimum of removal of dyes was found to be 94% at initial dye concentration 50 g/mL, modified fly ash dosage 250 g/mL, and pH of 2.0.

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Measurement Methodology for Fulfilling of Waste Acceptance Criteria for Low and Intermediate Level Radioactive Waste in Storages

ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2011-59016 ◽

2011 ◽

Author(s):

M. Sokcic-Kostic ◽

F. Langer ◽

R. Schultheis

Keyword(s):

Radioactive Waste ◽

Waste Treatment ◽

Storage Period ◽

Intermediate Level ◽

Acceptance Criteria ◽

Waste Storage ◽

Measurement Methodology ◽

Treatment Facilities ◽

Intermediate Level Radioactive Waste ◽

Radioactive Waste Storage

Low and intermediate level radioactive waste must be sorted and treated before it can be sent to radioactive waste storage. The waste must fulfil an extensive amount of acceptance criteria (WAC) to guarantee a safe storage period. NUKEM Technologies has a broad experience with the building and management of radioactive waste treatment facilities and has developed methods and equipment to produce the waste packages and to gather all the required information.

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Evaluation of Fresh Properties and Rheology of Mortar Using Carbon-Free Fly Ash and Normal Fly Ash

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1005.76 ◽

2020 ◽

Vol 1005 ◽

pp. 76-81

Author(s):

Ghawsaddin Nazari ◽

Shunya Yamanaka ◽

Shigeyuki Date

Keyword(s):

Fly Ash ◽

Setting Time ◽

Great Influence ◽

Mineral Admixture ◽

Mineral Admixtures ◽

Fresh Properties ◽

Initial Setting Time ◽

Usual Solution ◽

Initial Setting ◽

Flow Loss

Usage of mineral admixture and chemical admixture in concrete or mortar is a usual solution to reach full compaction, particularly where reinforcement blockage and lack of skilled labor happen. In this paper effect of mineral admixtures (Carbon-free fly ash, hereafter CfFA, and normal fly ash) on fresh properties and rheology of mortar have been investigated. As a result, it was confirmed that CfFA increased significantly the fluidity and air content of mortar in comparison to normal fly ash, both in 15% and 30% replacement; however, the flow loss and air stability within one hour were almost equal. In addition, the initial setting time has also been affected by variation of materials. The two mixing of 30% and 15% of CfFA had a shorter setting time in comparison to the mortar with normal fly ash. Furthermore, CfFA based mortar had a great influence on rheology of mortar. Compared to normal fly ash, CfFA Considerably decreased the plastic Viscosity and increased the productivity of the mortar, both in non-vibrated and vibrated condition, particularly those with 30% replacement.

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