Effect of limestone on rheological, shrinkage and mechanical properties of alkali – Activated slag/fly ash grouting materials

Xiang, Jichun; Liu, Leping; Cui, Xuemin; He, Yan; Zheng, Guangjian; Shi, Caijun

doi:10.1016/j.conbuildmat.2018.09.209

Cited by 85 publications

(20 citation statements)

References 34 publications

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“…A widely range of alkali-activatable industrial waste and by-products as well as a number of highly reactive materials with pozzolanic properties present in nature are presently available for use as raw materials ( Duxson et al 2008 ; De Rossi et al, 2020 ; Mobili et al 2020 ; Zhou et al, 2020 ). Small proportions of lime and/or Portland clinker as a source of calcium may also form part of the end binder ( Xiang et al, 2018 ). Possible solid-state activators are described in sub-section 2.3.…”

Section: Raw Materials Processing Industrial-scale Alkali Activated Binders Manufacturementioning

confidence: 99%

Portland Versus Alkaline Cement: Continuity or Clean Break: “A Key Decision for Global Sustainability”

et al. 2021

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This review undertakes rigorous analysis of much of the copious literature available to the scientific community on the use of alkali-activated binders (AABs) in construction. The authors’ main intention is to categorically refute arguments of that part of the scientific community underestimating or even dismissing the actual potential of AABs as alternatives to Portland cement (PC). The main premise invoked in support of those arguments is a presumed lack of material resources for precursors that would make AAB industrial-scale production unfeasible anywhere on the planet (a substantial number of scientific papers show that the raw materials required for AAB manufacture are in abundance worldwide). The review also analyses the role of alkaline activators in the chemistry of AABs; it is important to clarify and highlight that alkaline activators are not, by any means, confined to the two synthetic products (caustic soda and waterglass) mostly employed by researchers; other sustainable and efficient products are widely available. Finally, the review deals with the versatility of AAB production processes. The technologies required for the large scale manufacturing of AABs are mostly already in place in PC factories; actually no huge investment is required to transform a PC plant in a AAB factory; and quality and compositional uniformity of Alkaline Cements (binders produced through an industrial process) would be guaranteed. The last conclusions extracted from this review-paper are related with: i) the low carbon footprint of one-part AABs and ii) the urgent need of exploring standardization formulas allowing the commercial development of (sustainable) binders different from PC.

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Section: Raw Materials Processing Industrial-scale Alkali Activated Binders Manufacturementioning

confidence: 99%

Portland Versus Alkaline Cement: Continuity or Clean Break: “A Key Decision for Global Sustainability”

et al. 2021

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“…AAM paste behaves like a non-Newtonian fluid and its shear stress curve fits well with Bingham model [10,34], as shown in the following equation.…”

Section: Evolution Of Plastic Viscosity and Yield Stressmentioning

confidence: 60%

Evolution of flow properties, plastic viscosity, and yield stress of alkali-activated fly ash/slag pastes

2020

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The development of cementless concrete is attracting increasing attention in practice and research to reduce both greenhouse gas emissions and energy consumption of concrete. Alkali-activated materials (AAMs) are one of the viable alternatives to replace Portland cement due to their lower CO2 emissions. This study investigated the evolution of rheological parameters of alkali-activated fly ash/slag pastes as a function of time. Flowability and rheological measurements were carried out to determine the fluidity, plastic viscosity, and yield stress at different time intervals. The effects of the slag content, the concentration of SiO2 in the activator, and the solution/binder ratio were considered. Based on the results, the yield stress and plastic viscosity followed an increasing trend over time coinciding with a reduction in the paste fluidity. The plastic viscosity of AAM pastes was in the range of 1.3–9.5 Pa.s and 2.6–28.9 Pa.s after 5 min and 45 min of mixing, respectively. Given the same alkali activator, the higher content of slag the paste had, the higher yield stress the paste showed. In addition, this paper confirmed that the SiO2/Na2O ratio in the activator had no significant effect on yield stress, but a drastic effect of this ratio was found on the plastic viscosity of the paste.

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“…The slurry parameters in grouting holes, such as grouting pressure, grouting ratio, and grouting time, affect the grouting project's quality [8]. In recent years, many studies have been done on grouting materials' characteristics in cracks [9][10][11][12]. Li [13] studied the grout transport law from grouting holes in the Ordovician karst.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Crack Initiation and Propagation Thresholds of Inclined Cracks under High-Pressure Grouting in Ordovician Limestone

Dong

Yin

et al. 2021

Energies

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Control of the grouting pressure within the critical grouting pressure for crack propagation in Ordovician limestone can not only ensure grout penetration length, but also prevent the risk of creating an artificial water channel. Based on the fracture mechanics theory, a formula was proposed to calculate the critical grouting pressure of mixed mode I-II cracks in Ordovician limestone. The necessary conditions for tilted crack opening, the rationality of the existing empirical value of the maximum allowable grouting pressure was investigated based on the mechanical model. The RFPA2D-Flow numerical simulation software was used to evaluate the deduced theory. The research results show that the deduced theoretical calculation formula of the critical grouting pressure agrees with the numerical simulation results; when the mixed mode I-II fracture initiation occurs, the grouting pressure exceeds the perpendicular stress of the overlying rock; the greater the density of the overlying rock mass, the greater the value of grouting pressure for fracture initiation; when the side pressure coefficient was ≥1, crack dip angle increased and the grouting pressure for fracture initiation tended to decrease; and the empirical grouting pressure at the maximum allowable grouting pressure is 2.0–2.5 pw, which will not cause propagation and failure of the existing crack.

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Effect of limestone on rheological, shrinkage and mechanical properties of alkali – Activated slag/fly ash grouting materials

Cited by 85 publications

References 34 publications

Portland Versus Alkaline Cement: Continuity or Clean Break: “A Key Decision for Global Sustainability”

Portland Versus Alkaline Cement: Continuity or Clean Break: “A Key Decision for Global Sustainability”

Evolution of flow properties, plastic viscosity, and yield stress of alkali-activated fly ash/slag pastes

Analysis of Crack Initiation and Propagation Thresholds of Inclined Cracks under High-Pressure Grouting in Ordovician Limestone

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