Development of UHPC Using a Ternary Blend of Ultra-Fine Class F Fly Ash, Meta-kaolin and Portland Cement

2016 ◽  
Author(s):  
Zhengqi Li ◽  
Prasad Rao Rangaraju
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ternary Blend ◽  
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.

scholarly journals Natural Pozzolan as a Partial Substitute for Cement in Concrete

2013 ◽  
Vol 7 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Ghassan K. Al-Chaar ◽  
Mouin Alkadi ◽  
Panagiotis G. Asteris
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
Test Series ◽  
Natural Pozzolan ◽  
Industry Standards ◽  
Concrete Materials ◽  
Class F Fly Ash ◽  
Class F

In this paper, the use of natural pozzolan as a partial cement substitute in concrete materials is investigated. By means of a test series, four mixes using three types of natural pozzolan, as well as a Class F fly ash, are evaluated. The effectiveness of each pozzolan in controlling alkali-silica reactions has been studied. Correlations have been revealed between the mechanical properties of the proposed mixes and a Portland cement control mix. The results are also compared with industry standards for mortars made with fly ash and silica fume. The paper's findings indicate that one type of pozzolan may be used as a substitute for fly ash, but not for silica fume.

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