Mechanical and Durability Properties of Fly Ash-Based Geopolymer Concrete

Dutta, Arani; Moharana, Narayan Chandra

doi:10.1007/978-981-15-4577-1_61

Cited by 2 publications

(1 citation statement)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In many cases, comparative studies with hardened geopolymers and hydrated cement have clearly shown that the degree of degradation of hydrated cement is more pronounced than that of geopolymers [ 27 , 28 , 29 , 30 , 31 , 32 ], due to the calcium-rich hydration products of cement-based binders [ 30 ]. In this context, the differences of mass losses between geopolymers and hardened cement paste after acid exposure can be dramatic [ 33 ], and a significantly higher strength loss is found in the case of cement-based binders [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Sulfuric Acid-Induced Degradation of Potassium Silicate Activated Metakaolin Geopolymers by Semi-Quantitative SEM-EDX Analysis

et al. 2020

View full text Add to dashboard Cite

Geopolymers are synthesized by mixing powdery solids, rich in amorphous silicon and aluminum species, with an alkaline solution, which leads to the formation of an inorganic alumosilicate network. Their acid resistance is affected by the composition, the porosity, and pore size distribution of the hardened binder as well as the type and concentration of the acidic solution. In the present study, two geopolymer mixtures with varying liquid-to-solid ratios and Si/Al ratios were exposed to a sulfuric acid solution (pH = 1) and analyzed after different durations of exposure (7, 14, 28, 56, and 70 days) by using a light microscope and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). SEM-EDX elemental mapping was used to evaluate the degradation from depth profiles of silicon (Si), aluminum (Al), and potassium (K) leaching. The results clearly show the leaching kinetics of potassium and the dealumination of the network. The separate consideration of specific reaction steps in the course of degradation, namely the depth of erosion (DE), the depth of deterioration (DD), and the depth of reaction for certain elements (DR(e)), indicate a combination of chemical and diffusion controlled degradation mechanisms.

show abstract

Section: Introductionmentioning

confidence: 99%

Evaluation of Sulfuric Acid-Induced Degradation of Potassium Silicate Activated Metakaolin Geopolymers by Semi-Quantitative SEM-EDX Analysis

et al. 2020

View full text Add to dashboard Cite

show abstract

Dissolution of Volcanic Ash in Alkaline Environment for Cold Consolidation of Inorganic Binders

Dal Poggetto,

Douwe,

Stroscio

et al. 2024

Materials

View full text Add to dashboard Cite

A systematic study on the dissolution in concentrated alkali of two volcanic ashes from Cameroon, denoted as DAR and VN, is presented here. One volcanic ash, DAR, was 2 wt% richer in Fe and Ca and 4 wt% lower in Si than the other, designated as VN. Such natural raw materials are complex mixtures of aluminosilicate minerals (kaersutite, plagioclase, magnetite, diopside, thenardite, forsterite, hematite, and goethite) with a good proportion of amorphous phase (52 and 74 wt% for DAR and VN, respectively), which is more reactive than the crystalline phase in alkaline environments. Dissolution in NaOH + sodium silicate solution is the first step in the geopolymerisation process, which, after hardening at room temperature, results in solid and resistant building blocks. According to XRD, the VN finer ash powders showed a higher reactivity of Al-bearing soluble amorphous phases, releasing Al cations in NaOH, as indicated by IPC-MS. In general, dissolution in a strong alkaline environment did not seem to be affected by the NaOH concentration, provided that it was kept higher than 8 M, or by the powder size, remaining below 75 µm, while it was affected by time. However, in the time range studied, 1–120 min, the maximum element release was reached at about 100 min, when an equilibrium was reached. The hardened alkali activated materials show a good reticulation, as indicated by the low weight loss in water (10 wt%) when a hardening temperature of 25 °C was assumed. The same advantage was found for of the room-temperature consolidated specimens’ mechanical performance in terms of resistance to compression (4–6 MPa). The study of the alkaline dissolution of volcanic ash is, therefore, an interesting way of predicting and optimising the reactivity of the phases of which it is composed, especially the amorphous ones.

show abstract

Mechanical and Durability Properties of Fly Ash-Based Geopolymer Concrete

Cited by 2 publications

References 14 publications

Evaluation of Sulfuric Acid-Induced Degradation of Potassium Silicate Activated Metakaolin Geopolymers by Semi-Quantitative SEM-EDX Analysis

Evaluation of Sulfuric Acid-Induced Degradation of Potassium Silicate Activated Metakaolin Geopolymers by Semi-Quantitative SEM-EDX Analysis

Dissolution of Volcanic Ash in Alkaline Environment for Cold Consolidation of Inorganic Binders

Contact Info

Product

Resources

About