scholarly journals Lowering carbon foot print of Portland cement by class F fly ash substitution in mortar mixture in terms of workability and strength properties

2020 ◽  
Vol 2 (1) ◽  
pp. 34-46
Author(s):  
Asadullah ZAKI ◽  
Cengiz ATİŞ
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Strength Properties ◽  
Class F Fly Ash ◽  
Class F

scholarly journals Role of Ground Glass Fiber as a Pozzolan in Portland Cement Concrete

2017 ◽  
Vol 2629 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Hassan Rashidian-Dezfouli ◽  
Prasada Rao Rangaraju
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Glass Fiber ◽  
Chloride Ion ◽  
Ground Glass ◽  
Hardened Concrete ◽  
Portland Cement Concrete ◽  
Durability Properties ◽  
Class F Fly Ash ◽  
Class F

Millions of tons of fiberglass are produced annually for a variety of applications. Because of stringent quality requirements and operational characteristics of the manufacturing plants, a significant quantity of fiberglass that does not meet required specifications of the industry ends up as waste in landfills. This study investigated the use of ground glass fiber (GGF) that had been discarded by plants because it did not meet prescribed standards, as a supplementary cementitious material (SCM) for portland cement. Three replacement levels (10%, 20%, and 30% by mass) for portland cement in paste, mortar, and concrete mixtures were studied. Mechanical and durability properties of the mixtures were compared with two control mixtures: a mixture made up of 100% portland cement and a mixture with 25% Class F fly ash as a cement replacement material. It was observed in these studies that even though replacement of portland cement with GGF did not lead to any significant changes in the mechanical behavior of hardened concrete, there were significant improvements in durability properties at replacement levels up to as high as 20%. The use of GGF was found to improve significantly the resistance of mortar mixtures to alkali–silica reaction and sulfate attack. In addition, the use of GGF as an SCM significantly reduced the chloride ion permeability of concrete. Results of this study show that using GGF as an SCM can result in a better durability performance compared with a mixture with a similar level of Class F fly ash.

scholarly journals Laboratory Study on the Effectiveness of Limestone and Cementitious Industrial Products for Acid Mine Drainage Remediation

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 413
Author(s):  
Abdellatif Elghali ◽  
Mostafa Benzaazoua ◽  
Hassan Bouzahzah ◽  
Bruno Bussière
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Mine Tailings ◽  
Ordinary Portland Cement ◽  
Mine Drainage ◽  
Secondary Phases ◽  
Environmental Matrices ◽  
Acid Mine ◽  
Class F Fly Ash ◽  
Class F

Acid mine tailings may affect several environmental matrices. Here, we aimed to stabilize acid-generated mine tailings using several alkaline and cementitious amendments, which were tested in columns for 361 days. The alkaline amendments consisted of 10 and 20 wt.% limestone, while the cementitious amendments consisted of different binders at a total dosage of 5 wt.% binder. The different formulations for the cementitious amendments were: 50% Kruger fly ash and 50% class F fly ash; 20% ordinary Portland cement, 40% Kruger fly ash, and 40% class F fly ash; 80% ordinary Portland cement and 20% Kruger fly ash; and 20% ordinary Portland cement, 40% Kruger fly ash, and 40% fly ash. Kinetic testing on the amendment formulations showed that the pH values increased from <2.5 to circumneutral values (~7.5). The mobility of various chemical species was greatly reduced. Cumulative Fe released from the unamended tailings was ~342.5 mg/kg, and was <22 mg/kg for the amended tailings. The main mechanisms responsible for metal(loid) immobilization were the precipitation of secondary phases, such as Fe-oxyhydroxides, physical trapping, and tailing impermeabilization.

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