Composition and Microstructure of Alkali Activated Fly Ash Binder: Effect of the Activator

TL;DR: In this paper, the addition of carbon fibers showed negative effects on workability but positive effects on strength and such influences were discussed based on strength-workability relations, and correlations revealed two governing factors of liquid film thickness (LFT) and fiber factor with which the workability was modelled.

TL;DR: In this paper, the micro-mechanical properties of different phases of AAFA pastes were investigated by nanoindentation, and three phases, i.e., aluminosilicate gel, residual fly ash particles and pores, corresponding to three distinct peaks in the indentation modulus frequency plots.

TL;DR: In this paper, the characterization and leaching behaviors of three fly ashes taken from different low grade lignite-fired stations were characterized in terms of their physical, chemical, mineralogical and morphological properties.

Abstract: This paper statistically investigates the influence of parameter, namely curing temperature, molarity, NaOH/Na2SiO3, and activator‐to‐fly ash ratio on the compressive strength of low calcium fly ash‐based geopolymer concrete. This paper also investigates the effect of delay time prior to curing on the compressive strength of geopolymer concrete. The results of the experimental investigation show that these parameters notably influence the development of the mechanical strength of the final product. The statistical investigation shows that the early compressive strength is significantly affected by the synergistic effect of a linear term of curing temperature, molarity, and activator‐to‐fly ash ratio while NaOH/Na2SiO3 ratio was found to be not so statistically significant. The numerical algorithm formulated using regression analyses were simultaneously optimized by utilizing response optimizer method. A constitutive model which represents a relationship between the compressive strength and splitting tensile strength is also proposed.

TL;DR: In this article, a statistical study of the effect on the polymerization process of the molar ratio of the component oxides and the water content of the mixture showed the latter to be a critical parameter.

TL;DR: An overview on the methodologies for zeolite synthesis from CFA, and a detailed description of conventional alkaline conversion processes, with special emphasis on the experimental conditions to obtain high cation exchange capacity (CEC) zeolites is given in this article.

TL;DR: In this paper, the microscopic study of a set of alkali-activated and thermally cured fly ash samples enabled the authors to establish a descriptive model for the microstructural development of fly ash-based cementitious geopolymers.

TL;DR: In this article, a representative group of Spanish fly ashes has been characterised in order to determine its capacity for being alkali activated and give place to a material with cementitious properties.