Understanding the drying shrinkage performance of alkali-activated slag mortars

Ye, Hailong; Cartwright, Christopher; Rajabipour, Farshad; Radlińska, Aleksandra

doi:10.1016/j.cemconcomp.2016.11.010

Cited by 208 publications

(74 citation statements)

References 32 publications

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“…Němeček et al (2011) argue that AAM have an inherent modulus of elasticity in a range between 17 and 18 GPa and that this property appears to be, for a given formulation, independent of the precursor material or the type of curing regime employed. Ye et al (2017) produced blast furnace slag based AAM with modulus of elasticity varying between 13.25 and 20.71 GPa.…”

Section: Compressive Strength and Modulus Of Elasticitymentioning

confidence: 99%

Silica Fume as Precursor in the Development of Sustainable and High-Performance MK-Based Alkali-Activated Materials Reinforced With Short PVA Fibers

et al. 2019

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Alkali-activated materials (AAM) are currently the subject of increasing interest and research, mainly due to the possibility of reducing the carbon dioxide (CO 2 ) emissions in their production when compared to Portland cement (PC) and still achieve superior performance in many aspects when compared to traditional PC-based products. However, the use of sodium silicate (SS) as an alkaline activator in AAM is controversial when the aim is to reduce the environmental impact, as the production of the first also releases significant amount of CO 2 per ton of activator produced. Therefore, a demand has emerged for alternative silica-rich materials that could effectively reduce the demand for SS without compromising the mechanical behavior of the matrices and consequently the performance of fiber reinforced AAM. This paper investigates the gradual replacement (0-18% wt.) of metakaolin (MK) with silica fume (SF) in PVA-reinforced AAM, allowing the reduction of SS in the activator, also containing NaOH. Matrices with different composition were studied, i.e., with [SiO 2 ]/[Al 2 O 3 ] molar ratios of 3.0 and 3.8. All formulations were reinforced with 2% vol. of PVA fibers. The mechanical properties investigated were compressive strength, modulus of elasticity, flexural strength, and toughness. Apparent dry density, water absorption, and porosity of the composites were also assessed to give an indication of their durability. Single fiber pullout, fracture toughness, and direct tensile tests were also carried out in order to understand the deformation capability of the composites. Results indicated that the employment of SF may effectively reduce the demand for SS in the alkaline activators, in order to produce alkali-activated composites with lower environmental impact (reduced CO 2 emissions). Adjustments in the formulations may improve toughness in flexion in 170% with 30 wt.% reduction of SS in the activator, as well as improvements in deformation capability in tension. The development of strain-hardening MK-based AAM, however, has some challenging aspects that are also discussed.

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Section: Compressive Strength and Modulus Of Elasticitymentioning

confidence: 99%

Silica Fume as Precursor in the Development of Sustainable and High-Performance MK-Based Alkali-Activated Materials Reinforced With Short PVA Fibers

et al. 2019

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“…increased shrinkage magnitude but reduced shrinkage kinetics) of alkaliactivated slag (AAS) to the alkali incorporation in the main hydrated product, i.e. calcium-alumina-silicatehydrate (C-A-S-H) (Ye and Radlińska 2016c;Ye et al 2017a).…”

Section: Introductionmentioning

confidence: 99%

Effect of Alkalis on Cementitious Materials:Understanding the Relationship between Composition, Structure, and Volume Change Mechanism

Radlińska

2017

ACT

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Journal of Advanced AbstractPrevious studies demonstrated that alkalis can considerably affect the volumetric properties of hardened cementitious binders, including shrinkage, creep, and micro-cracking. The objective of this paper is to reexamine the effect of alkalis on the composition, nanostructure, phase stability, and morphology of calcium-silicate-hydrate (C-S-H) in cementitious materials, and to further propose a conceptual model bridging the C-S-H characters with its volume change mechanisms in alkali-enriched systems. The proposed microstructural model is an extension of the colloidal model of C-S-H considering the effect of alkalis. It is suggested that the presence of alkalis makes C-S-H more thermodynamically unstable and structurally disrupted, and easier to reorganize and redistribute upon drying-induced internal stresses or external loading. In addition, new experimental results regarding the influence of lithium on shrinkage and micro-cracking of alkali-activated blast-furnace slag are discussed. It shows that lithium addition can dramatically improve the cracking resistance and volumetric stability of alkali-activated slag.

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“…One of the shortcomings is that AAS is susceptible to shrinkage and microcracks [29][30][31][32]. Several studies have revealed AAS concrete has higher drying shrinkage than OPC concrete [31,[33][34][35][36][37][38][39][40]. For example, Palacios and Puertas [32] measured the drying shrinkage of waterglass-activated slag mortars.…”

Section: Introductionmentioning

confidence: 99%

Effect of Polypropylene Fiber on Properties of Alkali‐Activated Slag Mortar

Chen

Wang

2020

Advances in Civil Engineering

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Alkali-activated slag (AAS) is becoming an increasingly popular building material due to its excellent engineering properties and low CO 2 emissions, but its large shrinkage is an important reason to restrict its application and popularization. is work is aimed to study the possibility of inhibiting the shrinkage of AAS mortar by incorporating polypropylene fiber (PPF). For this, an experimental study was carried out to evaluate the effects of PPF content on setting time, fluidity, physical properties, mechanical properties, impact resistance, and microstructure of AAS mortar. e volume content of PPF is 0.05%, 0.1%, 0.15%, and 0.2%. e working, physical (porosity, water absorption, and bulk density), mechanical, shrinkage, and impact resistance properties of the AAS mortars were evaluated. e results show that incorporating PPF effectively reduces the shrinkage deformation of AAS mortar, significantly improves its impact resistance, enhances its toughness, and slightly improves its compressive strength in the later stage. At the same time, PPF delays the initial setting time of AAS mortar and reduces the fluidity, density, porosity, and water absorption of AAS mortar. SEM results show that the bridging effect of PPF between AAS mortars can inhibit the generation and propagation of cracks, improve the internal microstructure, and enhance the performance of AAS mortar.

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Understanding the drying shrinkage performance of alkali-activated slag mortars

Cited by 208 publications

References 32 publications

Silica Fume as Precursor in the Development of Sustainable and High-Performance MK-Based Alkali-Activated Materials Reinforced With Short PVA Fibers

Silica Fume as Precursor in the Development of Sustainable and High-Performance MK-Based Alkali-Activated Materials Reinforced With Short PVA Fibers

Effect of Alkalis on Cementitious Materials:Understanding the Relationship between Composition, Structure, and Volume Change Mechanism

Effect of Polypropylene Fiber on Properties of Alkali‐Activated Slag Mortar

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