Expansion of ordinary Portland cement paste varied with nano-MgO

Ye, Qing; Yu, Kaikai; Zhang, Zenan

doi:10.1016/j.conbuildmat.2014.12.113

Cited by 51 publications

(12 citation statements)

References 5 publications

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“…Wu et al [11] modified MEAs with a C-18 unsaturated fatty acid; this type of MEA can only hinder the early hydration of the MEA and reduce the amount of early expansion. Ye et al [12] prepared cement pastes with nano-MgO, and found that when the content of nano-MgO reached 8%, the soundness of concrete was still acceptable. Pei et al [13] proposed a mixture of paraffin and MgO, showing the admixtures can significantly compensate for the early shrinkage and reduce thermal accumulation.…”

Section: Introductionmentioning

confidence: 99%

Regulating the Expansion Characteristics of Cementitious Materials Using Blended MgO-Type Expansive Agent

2019

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To promote the application of MgO-type expansive agents (MEAs), the expansion stresses produced by compacted MEAs with different activities cured in water at 40 °C were measured using a self-designed expansion stress test apparatus. Based on these, different MEAs were divided into the early-type MgO expansive agent and the late-type MgO expansive agent classifications according to the stress curves of compacted MEAs. The two types of MEAs were blended with each other at different ratios and added into cement pastes. Results indicated that the expansion of the cement pastes added with blended MEAs lasted from the beginning to 200 days later, and the expansion characteristics can be regulated by adjusting the blending ratio of MEAs and the choice of types of MEAs. The results suggest that the expansion of MEAs can be improved by using blended MEAs in practical applications.

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Section: Introductionmentioning

confidence: 99%

Regulating the Expansion Characteristics of Cementitious Materials Using Blended MgO-Type Expansive Agent

2019

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“…Similarly, as demonstrated in Figure 5 and the key observations compiled in Table 2, the addition of other nanomaterials such as nano-alumina, nano-MgO, nano-ZnO, nano-TiO 2 , nano-clay, and carbon nanotubes (CNT) up to the optimum dosage improves the compressive strength [52,54,56,61,91,99,[129][130][131]. Clearly from the XRD images (Figure 6), the compressive strength increase is due to the flaw-bridging effect and filler effect at the nano level [45,[132][133][134][135][136], while agglomeration prevents the hydration process due to the formation of weak bonds within the mortar matrix [44,[137][138][139][140][141].…”

Section: Compressive Strengthmentioning

confidence: 60%

“…In other studies, an increase in compressive strength was observed against the incorporation of nano-silica and nano-metakaolin in high strength mortar at 400 and 250 • C, respectively [75,143]; this may be due to the higher rate of hydration due to the higher availability of SiO 2 . In [103], it was also observed that for nano-silica mortar, the compressive strength increased up to 450 • C and then decreased at higher temperatures up to 1000 • C. TiO2, nano-clay, and carbon nanotubes (CNT) up to the optimum dosage improves the compressive strength [52,54,56,61,91,99,[129][130][131]. Clearly from the XRD images (Figure 6), the compressive strength increase is due to the flaw-bridging effect and filler effect at the nano level [45,[132][133][134][135][136], while agglomeration prevents the hydration process due to the formation of weak bonds within the mortar matrix [44,[137][138][139][140][141].…”

Section: Compressive Strengthmentioning

confidence: 98%

“…Figure 5. Variations of 28-day compressive strength in cement mortar due to: (a) nano-silica and nano-alumina [30] and nano-clay [79]; (b) nano-titanium oxide [82], carbon nanotubes [54,110], nano-magnesium oxide [52], and nano-zinc oxide [54]. [30] and nano-clay [79]; (b) nano-titanium oxide [82], carbon nanotubes [54,110], nano-magnesium oxide [52], and nano-zinc oxide [54].…”

Section: Compressive Strengthmentioning

confidence: 99%

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confidence: 99%

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Comparative Overview of the Performance of Cementitious and Non-Cementitious Nanomaterials in Mortar at Normal and Elevated Temperatures

et al. 2021

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Nanotechnology has emerged as a field with promising applications in building materials. Nanotechnology-based mortars are examples of such building materials that have widespread applications in the construction industry. The main nanomaterials used in mortars include nano-silica, nano-magnesium oxide, nano-alumina, nano-titanium oxide, nano-zinc oxide, nano-clay, and nano-carbon. This review paper presents a summary of the properties and effects of these nanomaterials on cement mortar in terms of its fresh-state and hard-state properties. The fresh-state properties include the setting time, consistency, and workability, while the hard-state properties include mechanical properties such as compressive, flexural, tensile strengths, as well as the elasticity modulus, in addition to durability properties such as water absorption, shrinkage strain, strength loss due to freeze–thaw cycles, and chloride penetration, among others. Different nanomaterials cause different physical and chemical alterations within the microstructures of cement mortar. Therefore, the microstructural characterization and densification of mortar are discussed in detail at varying temperatures. In general, the involvement of nanomaterials in cement mortar influences the fresh-state properties, enhances the mechanical properties, and impacts the durability properties, while reducing the porosity present in the mortar matrix. Cementitious nanomaterials can create a pathway for the easy injection of binding materials into the internal microstructures of a hydration gel to impact the hydration process at different rates, whereas their non-cementitious counterparts can act as fillers. Furthermore, the research gaps and future outlook regarding the application of nanomaterials in mortar are discussed.

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