Chloride diffusion resistance and chloride binding capacity of fly ash-based geopolymer concrete

2020 ◽  
Vol 105 ◽  
pp. 103290 ◽  
Author(s):  
Amin Noushini ◽  
Arnaud Castel ◽  
James Aldred ◽  
Aditya Rawal
2020 ◽  
Vol 10 (18) ◽  
pp. 6271 ◽  
Author(s):  
Jun Liu ◽  
Jiaying Liu ◽  
Zhenyu Huang ◽  
Jihua Zhu ◽  
Wei Liu ◽  
...  

This paper experimentally studies the effects of fly ash on the diffusion, bonding, and micro-properties of chloride penetration in concrete in a water soaking environment based on the natural diffusion law. Different fly ash replacement ratio of cement in normal concrete was investigated. The effect of fly ash on chloride transportation, diffusion, coefficient, free chloride content, and binding chloride content were quantified, and the concrete porosity and microstructure were also reported through mercury intrusion perimetry and scanning electron microscopy, respectively. It was concluded from the test results that fly ash particles and hydration products (filling and pozzolanic effects) led to the densification of microstructures in concrete. The addition of fly ash greatly reduced the deposition of chloride ions. The chloride ion diffusion coefficient considerably decreased with increasing fly ash replacement, and fly ash benefits the binding of chloride in concrete. Additionally, a new equation is proposed to predict chloride binding capacity based on the test results.


Author(s):  
Yibiao Teng ◽  
Songhui Liu ◽  
Zhaocai Zhang ◽  
Jiangwei Xue ◽  
Xuemao Guan

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 359 ◽  
Author(s):  
Yunsu Lee ◽  
Seungmin Lim ◽  
Hanseung Lee

Whether chloride resistance is highly influenced by chloride binding capacity remains unknown. In this study, the chloride resistance of Portland cement-based mortar incorporating aluminate cement and calcium carbonate was investigated considering the chloride binding capacity, pore structures and chloride diffusion coefficient from non-steady state chloride migration and natural chloride diffusion. The cement hydrates were investigated using X-ray diffraction and thermogravimetric analysis. The chloride binding capacity was evaluated based on the chloride adsorption from the solutions using the adsorption isotherm. The aluminate cement, as an available alumina source, can stimulate the formulation of layered double hydroxides, which in turn can increase the chloride binding capacity. The results of mercury intrusion porosimetry show that non-substituted (control) and substituted (only aluminate cement) specimens have capillary pore volume 8.9 vol % and 8.2 vol %, respectively. However, the specimen substituted with aluminate cement and calcium carbonate shows a higher capillary volume (12.9 vol %), which correlates with the chloride diffusion coefficient. Although the specimen substituted with calcium carbonate has a higher chloride binding capacity than the control, it does not necessarily affect the decrease in the chloride diffusion coefficient. The capillary pore volume can affect not only the chloride diffusion but also the chloride adsorption.


Author(s):  
Víctor Alberto Franco-Luján ◽  
José Manuel Mendoza-Rangel ◽  
Víctor Guillermo Jiménez-Quero ◽  
Pedro Montes-García

2018 ◽  
Vol 175 ◽  
pp. 726-734 ◽  
Author(s):  
Baoguo Ma ◽  
Xiaohai Liu ◽  
Hongbo Tan ◽  
Ting Zhang ◽  
Junpeng Mei ◽  
...  

2021 ◽  
Vol 13 (11) ◽  
pp. 5969
Author(s):  
Salmabanu Luhar ◽  
Ismail Luhar ◽  
Demetris Nicolaides ◽  
Rajesh Gupta

Unfortunately, the production of cement impacts pessimistically on environments since it emits CO2—a principal Green House Gas (GHG)—encouraging the earth-heating dilemma. Moreover, it necessitates not only high temperature produced by the devouring of narrow natural mineral coal resources to obtain very high amounts of energy, but it also gulps down natural limestone deposits as a raw material that is found confined in nature to obtain intense energy. Quite recently, geopolymerisation—an exothermic process, through which geopolymeric binders can be produced by synthesis of a pozzolanic precursor rich in Alumina and Silica, for an instant, Fly Ash, with alkali solution for activation in an alkali medium at a low temperature and low operational energy—is recognized as a brilliantly promising alternative to conventional cement. That means, no elevated temperature and higher energy consuming reactions are essential any more as found associated with contemporary cement production. This research paper moves towards fulfilling the performance evaluation of durability studies viz., water permeability, sorptivity, sulphate resistance, acid resistance, salt resistance, chloride diffusion, drying shrinkage, and corrosion of fly ash based user and eco-friendly rubberized (containing rubber tyre fibres) geopolymer concrete. Comparisons of the outcomes have been made with its counterpart, which has unearthed that Rubberized Geopolymer Concrete proved to better concerning all the above-mentioned parameters than Rubberized OPC-Concrete.


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