Fly Ash/Blast Furnace Slag Geopolymer Repair System as a Sustainable Solution for the Maintenance of an Existing Bridge: Materials Design and Influence on Shear Capacity under Seismic Conditions

2015 ◽  
Vol 1105 ◽  
pp. 346-354 ◽  
Author(s):  
Gianluca Nestovito ◽  
Francesco Messina
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Coal Fly Ash ◽  
Shear Capacity ◽  
Maintenance Cost ◽  
Repair System ◽  
Geopolymer Concrete ◽  
Furnace Slag

This study deals with the paramount topic of sustainable and durable composite materials for repair of damaged existing bridge. Reinforced concrete is the most used composite system in structural design but, across several decades, it has shown some fragilities related to chemico-physical resistance. Durability improvement by means of innovative repair systems represent, therefore, a crucial economic parameter allowing a highly significant reduction of maintenance cost. A maintenance scenario is here simulated, considering a repair composite realized with a binary geopolymer binder, obtained by activating two industrial by-products, namely coal fly ash and blast furnace slag, in alkaline environment. Physico-mechanical characterization of geopolymer concrete is also performed, showing the suitability of this innovative repair system. In order to investigate the effectiveness of geopolymer, a 3D finite element model is developed in Sap2000 to represent the complex behavior of a full-scale Italian highway bridge. Numerical simulations are conducted by modeling the geopolymer concrete as a jacketing applied to the damaged piers. Results reveal that the designed repair system could increase shear capacity of bridge piers under seismic conditions, not neglecting the low cost of raw materials and the high durability of geopolymers.

scholarly journals Mechanical Behavior of Double Skinned Composite Hollow Columns using Geopolymer Concrete

2020 ◽  
Vol 8 (5) ◽  
pp. 4691-4696
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Steel Tube ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Ambient Temperatures ◽  
Granulated Blast Furnace Slag ◽  
Heat Curing ◽  
Furnace Slag

This paper comprises of the experimental study of double skinned (DSCFT) Composite hollow columns using Geopolymer concrete. The diameter-thickness (D/t) ratio and the hollowness ratio were consideredas main parameters in designing the specimens. The Geopolymer Concrete used in this project is the most promising technique. It is composed of fly-ash, fine aggregate, coarse aggregate and alkaline solution. By using large volume of ordinary Portland cement (OPC) concrete, the production of cement increases 3% annually. The production of one ton of cement directly liberates about 1 ton of CO2 and indirectly liberates 0.4 ton of CO2 to atmosphere. Among the greenhouse gases, CO2 contributes about 67% of global warming. In this respect fly ash based geopolymer mortar is highly considerable. But most of the previous works on fly ash-based geopolymers concrete reveals that hardening is due to heat curing, which is considered as a limitation for cast in situ applications at low ambient temperatures. In order to overcome this situation, replacing the Ground blast furnace slag with fly ash for various proportions to achieve geopolymer concrete suitable for curing without elevated heat. The Scope of this project is to find optimization level of Ground Granulated blast furnace slag in geopolymer concrete for curing in ambient condition and to analyze the compressive Strength of optimized GGBS based Geopolymer Concrete filled double skinned steel tube by varying the size of the steel tubes.

scholarly journals Characteristics of Blended Geopolymer Concrete Using Ultrafine Ground Granulated Blast Furnace Slag and Copper Slag

2020 ◽  
Vol 44 (6) ◽  
pp. 433-439
Author(s):  
Vijayasarathy Rathanasalam ◽  
Jayabalan Perumalsami ◽  
Karthikeyan Jayakumar
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Blast Furnace Slag ◽  
Copper Slag ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Strength Performance ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS), along with the copper slag (CPS) as replacement of fine aggregate (crushed stone sand). Various parameters considered in this study include different sodium hydroxide concentrations (10M, 12M and 14M); 0.35 as alkaline liquid to binder ratio; 2.5 as sodium silicate to sodium hydroxide ratio and cured in ambient curing condition. Further, geopolymer concrete was manufactured using fly ash as the prime source material which is replaced with UFGGBFS (0%, 5%, 10% and 15%). Copper slag has been used as replacement of fine aggregate in this study. Properties of the fresh manufactured geopolymer concrete were studied by slump test. Compressive strength of the manufactured geopolymer concrete was tested and recorded after curing for 3, 7 and 28 days. Microstructure Characterization of Geopolymer concrete specimens was done by Scanning Electron Microscope (SEM) analysis. Experimental results revealed that the addition of UFGGBFS resulted in an increased strength performance of geopolymer concrete. Also, this study demonstrated that the strength of geopolymer concrete increased with an increase in sodium hydroxide concentration. SEM results revealed that the addition of UFGGBFS resulted in a dense structure.

scholarly journals Domınance of materıal composıtıon on mechanıcal propertıes of normal and hıgh strength grade bınary blended geopolymer concrete

2020 ◽  
Vol 2 (3) ◽  
pp. 128-133
Author(s):  
Addepalli Mallinadh Kashyap ◽  
Tanimki Chandra Sekhar Rao ◽  
N.V.Ramana Rao
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Strength ◽  
Geopolymer Concrete ◽  
Green House Gases ◽  
Green House ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The utilisation of pozzolanic materials as the replacement to conventional cement material have the potentiality to mitigate the pollution caused by the émission of carbon based green house gases which are a main source for global warming problem. For every production of 1 ton of cement it was approximated that the emission of carbon based green house gases are about 1 ton. Keeping this in view, a new material called Geopolymer which was first coined by Davidovits has gained a lot of interest by the researchers. In this study, different molarity variations of NaOH in the order of 4M, 6M, 8M, 10M, 12M and 14M and also the blending of  mineral admixtures like Fly Ash and Ground Granulated Blast Furnace Slag with percentages (50%+50%) and the mechanical properties of normal M30 and high strength grade M70 binary blended Geopolymer concrete were studied after 28 days of ambient curing and were reported. The test results revealed that the effect of molar concentration of NaOH at 12 M is effective and the optimum replacement of mineral composition of source materials is (50%+50%) fly ash and ground granulated blast furnace slag.  

scholarly journals Mechanical Properties of Self-Compacting Geopolymer Concrete Using Fly Ash and GGBS

2018 ◽  
Vol 7 (1) ◽  
pp. 19-23
Author(s):  
S. Thirupathiraj .
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Geopolymer Concrete ◽  
Cement Concrete ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mix ◽  
Furnace Slag

Cement is the core content for the concrete mix. Manufacturing of cement causes CO2 emission which leads to the pollution, health and environmental problems like global warming to control over the adverse effect we can prefer geopolymer concrete which is not a cement concrete. Factory wastes such as fly ash, ground granulated blast furnace slag (GGBS), silica fume and Metakaolin can be used as alternate for cement. This study mainly focus on the ratio of fly ash and ground granulated blast furnace slag (GGBS) for optimum levels which nearly matches the cement concrete properties. This study involves the various tests like slump flow, compression testing, split tensile strength and flexural strength of self-compacting geopolymer concrete. Self-compacting concrete is a highly flowable concrete that spreads into the form without the need of mechanical vibration. Self-compacting concrete is a non-segregating concrete that is placed by means of its own weight. The advantages include improved constructability, Labour reduction, bond to steel, Flow into complex forms, reduced equipment wear etc. The aim of this study is to achieve an optimum self-compacting concrete geopolymer concrete mix proportion using fly ash and ground granulated blast furnace slag (GGBS). Then the study will be further extended by investigating the durability properties of self-compacting geopolymer concrete.

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