Supplementary Cementitious Materials

Snellings, Ruben; Mertens, Gilles; Elsen, Jan

doi:10.2138/rmg.2012.74.6

Cited by 380 publications

(166 citation statements)

References 270 publications

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“…2). This is the principal cementitious component of environmentally friendly concretes that partially replace Portland cement with alumino-silicate supplemental materials to reduce CO 2 emissions associated with cement manufacture and improve chemical durability, at least at the decadal time scale (20,21). X-ray powder and microdiffraction ( Fig.…”

Section: Trajanic Mortar Reproductionmentioning

confidence: 99%

Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

Jackson¹,

Landis

Brune

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

167

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The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime-volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium-aluminum-silicate-hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8-0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strät-lingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45-0.75. Dense clusters of 2-to 30-μm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clastsupported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.Roman concrete | volcanic ash mortar | fracture toughness | interfacial zone | strätlingite

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Section: Trajanic Mortar Reproductionmentioning

confidence: 99%

Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

Jackson¹,

Landis

Brune

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

167

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“…Another environmental strategy for reducing the negative impact of the cement industry is the partial substitution of cement by by-products materials (such as fly ash or slag) also known as supplementary cementitious materials (SCMs) [17][18][19]. The environmental benefits of the use of waste materials are two folds, lower CO 2 emissions because of the clinker reduction, and the valorization of a "useless" product.…”

Section: Introductionmentioning

confidence: 99%

Hydration studies of calcium sulfoaluminate cements blended with fly ash

García-Maté

Torre

León‐Reina

et al. 2013

Cement and Concrete Research

156

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The main objective of this work is to study the hydration and properties of calcium sulfoaluminate cement pastes blended with fly ash (FA) and the corresponding mortars at different hydration ages. Laboratory X-ray powder diffraction, rheological studies, thermal analysis, porosimetry and compressive strength measurements were performed. The analysis of the diffraction data by Rietveld method allowed quantifying crystalline phases and overall amorphous contents. The studied parameters were: i) FA content, 0, 15 and 30 wt.%; and ii) water addition, water-to-CSA mass ratio (w/CSA = 0.50 and 0.65), and water-to-binder mass ratio (w/b = 0.50). Finally, compressive strengths after 6 months of 0 and 15 wt.% FA [w/CSA = 0.50] mortars were similar: 73 ± 2 and 72 ± 3 MPa, respectively. This is justified by the filler effect of the FA as no strong evidences of reactivity of FA with CSA were observed. These results support the partial substitution of CSA cements with FA with the economic and environmental benefits.

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“…If no actions are taken the share of cement production on global CO 2 emission is likely to increase substantially from 5-8% to 25% or more by 2050 [4]. With limited supplies of high-quality SCMs such as blast furnace slags (300-360 Mt/y) [5], future CO 2 emission reductions will need to depend on an expanded use of other SCMs such as coal combustion fly ashes [6], or natural pozzolans [7] and thermally activated clays [8]. Moreover, restructuring of the energy market towards renewables and increased recycling of energyintensive materials such as metals will lead to locally declining supplies of conventional SCMs (blast furnace slag, fly ash) [9].…”

Section: The Sustainability Challengementioning

confidence: 99%

Assessing, Understanding and Unlocking Supplementary Cementitious Materials

Snellings

2016

RILEM Tech Lett

204

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The partial replacement of Portland clinker by supplementary cementitious materials (SCM) is one of the most popular and effective measures to reduce both costs and CO2 emissions related to cement production. An estimated 800 Mt/y of blast furnace slags, fly ashes and other materials are currently being used as SCM, but still the cement industry accounts for 5-8% of global CO2 emissions. If no further actions are taken, by the year 2050 this share might even rise beyond 25%. There is thus a clear challenge as to how emissions will be kept at bay and sustainability targets set by international commitments and policy documents will be met. Part of the solution will be a further roll-out of blended cements in which SCMs constitute the main part of the binder to which activators such as Portland cement are added. Since supply concerns are being raised for conventional high-quality SCMs it is clear that new materials and beneficiation technologies will need to step in to achieve further progress. This paper presents opportunities and challenges for new SCMs and demonstrates how advances towards more powerful and reliable characterisation techniques help to better understand and exploit SCM reactivity.

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Supplementary Cementitious Materials

Cited by 380 publications

References 270 publications

Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

Hydration studies of calcium sulfoaluminate cements blended with fly ash

Assessing, Understanding and Unlocking Supplementary Cementitious Materials

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