Performance deterioration of fly ash/slag-based geopolymer composites subjected to coupled cyclic preloading and sulfuric acid attack

Qu, Fulin; Li, Wengui; Wang, Kejin; Zhang, Shishun; Sheng, Daichao

doi:10.1016/j.jclepro.2021.128942

Cited by 47 publications

(17 citation statements)

References 70 publications

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“…Mass loss or residual mass of specimens is widely used to identify the degradation of cementitious materials under aggressive acidic environments [19,24,59,78,81,84,85,88,[108][109][110]114,147,[157][158][159][160][161][162][163][164][165][166][167]. Mass loss is a relatively simple and non-destructive technique, but can provide misleading results when comparing different binders [80].…”

Section: Physical Measurements Of Degradationmentioning

confidence: 99%

“…On the other hand, the degraded parts of AABs after acid attack have a much lower alkalinity. This means that pH indicators like phenolphthalein solution [78,100,114,157,[159][160][161]170] and thymol blue [170] can be used to identify the corrosion depth after acid attack. Measuring the residual size of AABs specimens generally requires mechanical methods (i.e.…”

Section: Physical Measurements Of Degradationmentioning

confidence: 99%

“…Compressive strength reduction or residual compressive strength of specimens is widely used to identify the effect of acid attack on AABs [34,75,76,78,81,85,100,101,[108][109][110]114,132,[157][158][159][160][161][163][164][165][166][167][168]. Compressive strength reduction reveals the global decrease in strength capacity after acid attack.…”

Section: Physical Measurements Of Degradationmentioning

confidence: 99%

See 2 more Smart Citations

Acid resistance of alkali-activated binders: A review of performance, mechanisms of deterioration and testing procedures

Aiken¹,

Kwasny³

et al. 2022

Construction and Building Materials

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Section: Physical Measurements Of Degradationmentioning

confidence: 99%

Section: Physical Measurements Of Degradationmentioning

confidence: 99%

Section: Physical Measurements Of Degradationmentioning

confidence: 99%

See 1 more Smart Citation

Acid resistance of alkali-activated binders: A review of performance, mechanisms of deterioration and testing procedures

Aiken¹,

Kwasny³

et al. 2022

Construction and Building Materials

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“…In despite of the multiple protective barriers placed around the large-volume waste forms, the mass and heat transfer still occurred between the waste forms and the environment after near-surface disposal under real service conditions [9]. Due to the complexity of the underground environment (thermal-hydrological-mechanical-chemical), the combined action of these factors will lead to the degradation of the waste forms, including the dissolution and decalcification which would result in the loose pore structure and weaken the microhardness of waste forms [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

The Transformation and Leachability of Fly Ash/Cement Waste Forms Subjected to the Simultaneous Effect of Heat and Chemistry

Zheng

Hua

et al. 2022

Advances in Materials Science and Engineering

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The utilization of cement waste forms with high content of fly ash is a potential method in large-volume immobilization of low- and intermedium-level radioactive waste at near-surface. However, the migration behavior of radionuclides in fly ash/cement waste forms under geological environment is still unclear. This study researched the transformation of products, pore structure as well as the leachability of Ca2+, Na+, and simulated radioactive nuclides (Sr2+ and Cs+) in fly ash/cement waste forms under simultaneous effect through X-ray diffractometer (XRD), mercury intrusion porosimetry (MIP), and inductively coupled plasma optical emission spectroscopy (ICP-OES). Furthermore, the relationship between the decalcification and the leaching of Sr2+ and Cs+ was established by the fitting curves of apparent diffusion coefficient. The results indicated that the products of fly ash/cement waste forms were kept stable under simultaneous effect and the pore structure has excellent resistance to temperature. The increasing salt concentrations of leachant and temperature promoted the leaching of radionuclides while the protection layer formed at 60–80°C inhibited this phenomenon. The relationship of apparent diffusion coefficient between Sr2+ and Ca2+ was quadratic nonlinear, while the relationship between Cs+ and Ca2+ showed a linear relationship. Compared to cement waste forms, fly ash/cement waste forms were more stable. In addition, the long-term retention ability of fly ash/cement waste forms to Cs+ was more outstanding than Sr2+.

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“…Thus, it is significant to investigate the sulfuric-acid resistance of geopolymers respectively prepared from different binding materials: metakaolin and low-calcium and high-calcium fly ash. Besides, most scholars only take a single concentration of alkali activator into consideration [ 26 , 27 ], ignoring the influence of alkali activator concentration on the acid resistance of geopolymers. Different concentrations of alkali activator should be considered to prepare the geopolymer mixtures.…”

Section: Introductionmentioning

confidence: 99%

Resistance to Sulfuric Acid Corrosion of Geopolymer Concrete Based on Different Binding Materials and Alkali Concentrations

et al. 2021

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Geopolymer binder is expected to be an optimum alternative to Portland cement due to its excellent engineering properties of high strength, acid corrosion resistance, low permeability, good chemical resistance, and excellent fire resistance. To study the sulfuric acid corrosion resistance of geopolymer concrete (GPC) with different binding materials and concentrations of sodium hydroxide solution (NaOH), metakaolin, high-calcium fly ash, and low-calcium fly ash were chosen as binding materials of GPC for the geopolymerization process. A mixture of sodium silicate solution (Na2SiO3) and NaOH solution with different concentrations (8 M and 12 M) was selected as the alkaline activator with a ratio (Na2SiO3/NaOH) of 1.5. GPC specimens were immersed in the sulfuric acid solution with the pH value of 1 for 6 days and then naturally dried for 1 day until 98 days. The macroscopic properties of GPC were characterized by visual appearance, compressive strength, mass loss, and neutralization depth. The materials were characterized by SEM, XRD, and FTIR. The results indicated that at the immersion time of 28 d, the compressive strength of two types of fly ash-based GPC increased to some extent due to the presence of gypsum, but this phenomenon was not observed in metakaolin-based GPC. After 98 d of immersion, the residual strength of fly ash based GPC was still higher, which reached more than 25 MPa, while the metakaolin-based GPC failed. Furthermore, due to the rigid 3D networks of aluminosilicate in fly ash-based GPC, the mass of all GPC decreased slightly during the immersion period, and then tended to be stable in the later period. On the contrary, in metakaolin-based GPC, the incomplete geopolymerization led to the compressive strength being too low to meet the application of practical engineering. In addition, the compressive strength of GPC activated by 12 M NaOH was higher than the GPC activated by 8 M NaOH, which is owing to the formation of gel depended on the concentration of alkali OH ion, low NaOH concentration weakened chemical reaction, and reduced compressive strength. Additionally, according to the testing results of neutralization depth, the neutralization depth of high-calcium fly ash-based GPC activated by 12 M NaOH suffered acid attack for 98 d was only 6.9 mm, which is the minimum value. Therefore, the best performance was observed in GPC prepared with high-calcium fly ash and 12 M NaOH solution, which is attributed to gypsum crystals that block the pores of the specimen and improve the microstructure of GPC, inhibiting further corrosion of sulfuric acid.

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Performance deterioration of fly ash/slag-based geopolymer composites subjected to coupled cyclic preloading and sulfuric acid attack

Cited by 47 publications

References 70 publications

Acid resistance of alkali-activated binders: A review of performance, mechanisms of deterioration and testing procedures

Acid resistance of alkali-activated binders: A review of performance, mechanisms of deterioration and testing procedures

The Transformation and Leachability of Fly Ash/Cement Waste Forms Subjected to the Simultaneous Effect of Heat and Chemistry

Resistance to Sulfuric Acid Corrosion of Geopolymer Concrete Based on Different Binding Materials and Alkali Concentrations

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