Mechanical Properties of Ultra-High-Performance Concrete Containing Natural Pozzolan and Metakaolin

Mousavinezhad, Seyedsaleh; Gonzales, Gregory J.; Toledo, William K.; Garcia, Judit M.; Newtson, Craig M.

doi:10.1061/9780784484609.022

Cited by 6 publications

(10 citation statements)

References 6 publications

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“…However, the fact that pumicite mixtures had comparable 56-day compressive strengths to the control mixture indicate that the natural pozzolan reaction had finally progressed to a point of equivalency with the fly ash reaction. This occurred because the natural pozzolan was more reactive than fly ash after 28 days, which is consistent with observations by other researchers [ 54 , 58 ]. Due to the diminishing availability of fly ash, lower compressive strengths at 28 days for mixtures containing natural pozzolan may need to be tolerated to capture the economic and durability benefits of the natural pozzolan.…”

Section: Resultssupporting

confidence: 92%

“…Results indicate that substituting pumicite, metakaolin, and GGBFS for fly ash increased HRWRA demand (decreased workability). This can be attributed to pumicite, metakaolin, and GGBFS being more angular than fly ash, which has spherical particles that create a ball-bearing effect in the fluid state [ 44 , 54 , 55 ]. Pumicite and metakaolin have greater specific surface areas than fly ash ( Table 1 ) that lead to greater water absorption rates [ 56 , 57 ].…”

Section: Resultsmentioning

confidence: 99%

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A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials

et al. 2023

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Ultra-high performance concrete (UHPC) is a novel cement-based material with exceptional mechanical and durability properties. Silica fume, the primary supplementary cementitious material (SCM) in UHPC, is expensive in North America, so it is often substituted with inexpensive class F fly ash. However, future availability of fly ash is uncertain as the energy industry moves toward renewable energy, which creates an urgent need to find cost-effective and environmentally friendly alternatives to fly ash. This study investigated replacing cement, fly ash, and silica fume in UHPC mixtures with ground granulated blast-furnace slag (GGBFS), metakaolin, and a natural pozzolan (pumicite). To identify acceptable UHPC mixtures (28-day compressive strength greater than 120 MPa), workability, compression, and flexural tests were conducted on all mixtures. Then, durability properties including shrinkage, frost resistance, and chloride ion permeability (rapid chloride permeability and surface resistivity tests) were evaluated for the acceptable UHPC mixtures. Results showed that 75, 100, and 40% of fly ash in the control mixture could be replaced with pumicite, metakaolin, and GGBFS, respectively, while still producing acceptable strengths. Flexural strengths were greater than 14.20 MPa for all mixtures. For durability, UHPC mixtures had shrinkage strains no greater than 406 μstrain, durability factors of at least 105, and “very low” susceptibility to chloride ion penetration, indicating that these SCMs are suitable candidates to completely replace fly ash and partially replace silica fume in non-proprietary UHPC.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials

et al. 2023

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“…SCMs in concrete generally improve mechanical and durability properties through pozzolanic reactions that lead to secondary calcium silicate hydrate (CSH) production that fills pore space, improves density, and reduces permeability [10,11,[23][24][25][26]. Decreasing concrete permeability increases resistance to chloride ion penetration, which reduces the probability of reinforcing steel corrosion and extends the life expectancy of a concrete structure.…”

Section: Other Durability Issuesmentioning

confidence: 99%

“…For decades, SCMs have been used to reduce Portland cement content and mitigate durability issues such as ASR expansion, degradation caused by freezing and thawing, chloride ion penetration, and attack by sulfates in different types of concrete [1,10,11,26,33,34]. In many cases, it has been demonstrated that SCMs can also enhance mechanical properties of concrete.…”

Section: Supplamantry Cementiouos Materialsmentioning

confidence: 99%

“…There are several types of SCMs, such as natural pozzolans, metakaolin, or ground granulated blast-furnace slag (GGBFS) that appear to be potential alternatives to fly ash in concrete. As the effects of metakaolin and GGBFS in ultra-high performance concrete mixtures have been evaluated in previous studies conducted by the authors [10,11], a natural pozzolan (pumicite) was selected in this study since it is locally available in New Mexico, USA, where the research was conducted. In the United States, natural pozzolans have not been cost-competitive with fly ash until recently so they have not been widely used as SCMs.…”

Section: Introductionmentioning

confidence: 99%

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A Locally Available Natural Pozzolan as a Supplementary Cementitious Material in Portland Cement Concrete

Mousavinezhad,

Garcia,

Toledo

et al. 2023

Buildings

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For several decades, class F fly ash has been an attractive supplementary cementitious material, at least in part, due to its ability to reduce Portland cement consumption and mitigate alkali-silica reactions in concrete. However, fly ash availability is becoming uncertain as the energy industry decommissions coal burning power plants as it transitions to renewable energy production. This situation creates a need to identify viable and sustainable alternative supplementary cementitious materials. There are several types of supplementary cementitious materials, such as natural pozzolans, metakaolin, or ground granulated blast-furnace slag, which appear to be potential alternatives to fly ash in concrete. In this research, a locally available natural pozzolan (pumicite) was selected to replace fly ash in concrete. After conducting alkali-silica reaction tests on mortar mixtures, rheological and strength properties, shrinkage, resistance to freezing and thawing, and chloride ion permeability of concrete mixtures containing different amounts of fly ash and natural pozzolan were evaluated. The results showed that pumicite was more effective than fly ash at mitigating the alkali-silica reaction, and a pumicite content of 20% was necessary to mitigate the alkali-silica reaction. Ternary mixtures containing both pumicite and fly ash were the most effective cementitious materials combinations for mitigating the alkali-silica reaction expansion. Additionally, pumicite provided acceptable compressive strength and modulus of rupture values (greater than 4.0 MPa) that exceeded the flexural strengths provided by established mixtures containing only fly ash. Shrinkage and durability factor values for all mixtures were less than 710 μstrain and greater than 75, which are generally considered acceptable. Additionally, all mixtures with acceptable alkali-silica reaction expansions had very low chloride permeability. These results indicate that pumicite can be a reliable alternative for fly ash.

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Stabilization of Expansive Soils with Agricultural Waste

Tarhuni,

Hossain

2024

Lecture Notes in Civil Engineering

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Mechanical Properties of Ultra-High-Performance Concrete Containing Natural Pozzolan and Metakaolin

Cited by 6 publications

References 6 publications

A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials

A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials

A Locally Available Natural Pozzolan as a Supplementary Cementitious Material in Portland Cement Concrete

Stabilization of Expansive Soils with Agricultural Waste

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