Optimizing supplementary cementitious material replacement to minimize the environmental impacts of concrete

Knight, Kelli A.; Cunningham, Patrick R.; Miller, Sabbie A.

doi:10.1016/j.cemconcomp.2023.105049

Cited by 48 publications

(3 citation statements)

References 32 publications

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“…This includes strategies like eliminating the residual adhesive mortar from the aggregate's surface and enhancing the adhesive mortar's performance. The second approach entails enhancing the overall quality of synthesized recycled concrete directly by incorporating supplementary materials, such as polymers and mineral admixtures [25][26][27][28][29][30]. Heat treatment stands out as a favorable approach for dissolving weakly bonded mortar because of its straightforward application and cost efficiency.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Mathematical Modeling of Mechanical Properties of Basalt Fiber-Reinforced Recycled Concrete Containing a High Content of Construction Waste

Chen,

Chen

2023

Construction Materials

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Herein, we conducted an experimental test on basalt fiber-reinforced concrete with a high content of construction and demolition waste and then established some mathematical models based on Taylor’s formula. The concrete was prepared by using recycled clay brick powder in place of cement and recycled coarse aggregates as a substitution for natural coarse aggregates. The basalt fiber in weight dosages of 0, 0.1, 0.3, and 0.5% was used for reinforcement. The results showed that the compressive strength of concrete declined as the content of recycled aggregates increased, while the compressive strength first increased and then decreased as the basalt fiber dosage lifted. Regarding the splitting tensile strength, the reinforcement effect of basalt fiber in concrete with a high content of recycled aggregate is more significant when compared to its to its counterpart, which contains no or fewer recycled aggregates. The concrete with 0.5% basalt fiber dosage and 100% recycled aggregate content retains an equivalent compressive strength as to that of natural aggregate concrete and has about a 90% splitting tensile strength. In addition, the cubic function in comparison to the quadratic function has a higher fitting accuracy.

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Section: Introductionmentioning

confidence: 99%

Experimental Study and Mathematical Modeling of Mechanical Properties of Basalt Fiber-Reinforced Recycled Concrete Containing a High Content of Construction Waste

Chen,

Chen

2023

Construction Materials

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“…Concrete construction accounts for approximately 7% of global greenhouse gas (GHG) emissions [1]. The worldwide demand for concrete continues to grow: with the concrete consumption is expected to increase by more than 20% by 2050 [2]. The majority of GHG emissions from concrete are from the calcining and burning of limestone and clays during the production of ordinary Portland cement (OPC), the binder in concrete [3] [4].…”

Section: Introductionmentioning

confidence: 99%

Microstructure analysis of cement-biochar composites

Lorenzoni,

Cunningham,

Fritsch

et al. 2023

Preprint

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The use of biochar, as a concrete constituent has been proposed to reduce the massive carbon footprint of concrete. Due to the low density and complex porosity of biochar, microstructural analysis of Portland cement-biochar composites is challenging. This causes challenges to the improvement of micro-scale understanding of biochar composite behavior. This work advances the microstructural understanding of Portland cement composites with 0, 5, and 25 volume percent (vol%) of cement replaced with wood biochar by applying common characterization techniques of mercury intrusion porosimetry (MIP), gas sorption, scanning electron microscopy (SEM), and isothermal heat flow calorimetry (HFC) in conjunction with 1H nuclear magnetic resonance (NMR) and micro-X-ray computed tomography (XCT) analysis techniques. The combination of these techniques allows a multi-scale investigation of the effect of biochar on the microstructure of cement paste. NMR and XCT techniques allow the observation and quantification of the pore space. HFC and MIP confirmed that biochar absorbs moisture and reduces the effective water-cement ratio. Gas sorption, MIP, and NMR shows that 5 vol% replacement does not significantly affect the gel and capillary pore structures. Results from XCT (supported by MIP and NMR) show that biochar can reduce the formation of larger pores. Importantly, XCT results suggest that biochar can act as a flaw in the microstructure which could explain reductions in the mechanical properties. Overall, the mechanical properties already analyzed in the literature are consistent with the microstructural changes observed, and these results highlight the need to carefully tailor the volume fraction of biochar to control its effect on the paste microstructure.

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“…In light of the cement industry's disproportionally large carbon footprint, researchers worldwide have been prompted to develop and implement various solutions to curb emissions and achieve decarbonation of cement production [7][8][9]. The three main approaches are: (1) improving energy efficiency and shifting to renewable or low-carbon fuels like biomass [10]; (2) reducing clinker content by increasing supplementary cementitious materials (SCMs) [11][12][13]; and (3) applying carbon capture, utilization, and storage (CCUS) technologies [14][15][16][17]. While switching to alternative fuels and optimizing energy can reduce CO 2 from fuel combustion, the calcination process inevitably releases CO 2 as an intrinsic byproduct.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Aragonite Whiskers by Co-Carbonation of Waste Magnesia Slag and Magnesium Sulfate: Enhancing Microstructure and Mechanical Properties of Portland Cement Paste

Ye,

Liu,

Fang

et al. 2023

Buildings

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This study focused on the synthesis of aragonite whiskers through a synergistic wet carbonation technology utilizing waste magnesia slag (MS) and magnesium sulfate (MgSO4), aiming to improve the microstructure and mechanical properties of ordinary Portland cement (OPC) paste. The influence of MgSO4 concentration on the wet carbonation process, phase composition, and microstructure of MS was investigated. Furthermore, the effect of incorporating carbonated MS (C-MS) on the mechanical properties and microstructure of Portland cement paste was evaluated. Results showed that appropriate MgSO4 concentrations favored aragonite whisker formation. A concentration of 0.075 M MgSO4 yielded 86.6% aragonite with high aspect ratio nanofibers. Incorporating 5% of this C-MS into OPC increased the seven-day compressive strength by 37.5% compared to the control OPC paste. The improvement was attributed to accelerated hydration and reduced porosity by the filling effect and microfiber reinforcement of aragonite whiskers. MS demonstrated good CO2 sequestration capacity during carbonation. This study provides an effective method to synthesize aragonite whiskers from waste MS and use it to enhance cementitious materials while reducing CO2 emissions, which is valuable for the development of a sustainable cement industry.

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Optimizing supplementary cementitious material replacement to minimize the environmental impacts of concrete

Cited by 48 publications

References 32 publications

Experimental Study and Mathematical Modeling of Mechanical Properties of Basalt Fiber-Reinforced Recycled Concrete Containing a High Content of Construction Waste

Experimental Study and Mathematical Modeling of Mechanical Properties of Basalt Fiber-Reinforced Recycled Concrete Containing a High Content of Construction Waste

Microstructure analysis of cement-biochar composites

Synthesis of Aragonite Whiskers by Co-Carbonation of Waste Magnesia Slag and Magnesium Sulfate: Enhancing Microstructure and Mechanical Properties of Portland Cement Paste

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