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

Author(s):  
Hassan Rashidian-Dezfouli ◽  
Prasada Rao Rangaraju

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.

2017 ◽  
Vol 67 (328) ◽  
pp. 136 ◽  
Author(s):  
H. Rashidian-Dezfouli ◽  
P. R. Rangaraju

Strength and durability characteristics of geopolymers produced using three precursors, consisting of fly ash, Ground Glass Fiber (GGF), and glass-powder were studied. Combinations of sodium hydroxide and sodium silicate were used as the activator solutions, and the effect of different sodium and silica content of the activators on the workability and compressive strength of geopolymers was investigated. The parameters used in this study were the mass ratio of Na2O-to-binder (for sodium content), and SiO2-to-Na2O of the activator (for silica content). Geopolymer mixtures that achieved the highest compressive strength from each precursor were assessed for their resistance to alkali-silica reaction and compared against the performance of portland cement mixtures. Test results revealed that GGF and fly ash-based geopolymers performed better than glass-powder-based geopolymer mixtures. The resistance of GGF-based and fly ash-based geopolymers to alkali-silica reaction was superior to that of portland cement mixtures, while glass-powder-based geopolymer showed inferior performance.


2014 ◽  
Vol 60 (1) ◽  
pp. 55-75 ◽  
Author(s):  
P. Gomathi ◽  
A. Sivakumar

Abstract This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fl y ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2-100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.


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