Industrially interesting approaches to “low-CO2” cements

Gartner, E.M.

doi:10.1016/j.cemconres.2004.01.021

Cited by 1,636 publications

(646 citation statements)

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“…There are many environmental issues associated with the production of Ordinary Portland cement (OPC), such as consumption of 5% of natural resources, and generation of 5-7 % of total global anthropogenic carbon dioxide emissions [1][2][3][4]. This has led to an urgent need for the development of alternative materials that may provide technically viable alternative solutions to conventional cementitious concrete, with more favourable environmental credentials.…”

Section: Introductionmentioning

confidence: 99%

Development of geopolymer mortar under ambient temperature for in situ applications

Al-Majidi

Λαμπρόπουλος

Cundy

et al. 2016

Construction and Building Materials

305

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Geopolymer concrete technology involves production of more environmentally friendly waste material-based concrete which could be a viable solution for conventional concrete replacement. Typical fly ash-based geopolymer concrete however requires high temperature curing treatment in order to develop sufficient early strength properties, which is considered a severe limitation for cast-in-place concrete applications. Most previous studies on geopolymer concrete have focused on the properties of concretes pre-hardened by heat curing and/ or by aggressive chemical treatment (e.g. alkali activation using concentrated sodium hydroxide (NaOH)). The current study presents an extensive experimental investigation on the mechanical and microstructural properties of geopolymer concrete mixes prepared with a combination of fly ash and slag cured under ambient temperature. 'User friendly' geopolymer mixes were produced using fly ash (FA) and Ground Granulated Blast furnace Slag (GGBS) mixed together with potassium silicate with molar ratio equal to 1.2 (as the activator) and water. The results indicated that heat curing treatment can be avoided by partial replacement of fly ash with slag. The compressive strength of the examined mixes was found to be in the range of 40-50MPa for 40 % and 50 % GGBS replacement mixtures respectively. Moreover, the flexural and direct tensile strengths of geopolymer mixes are considerably improved as the GGBS content is increased.Based on FTIR and SEM/EDS analysis, the inclusion of a higher content of GGBS resulted in a denser structure by formation of more hydration products.Keywords: Fly ash, slag, ambient temperature, user friendly geopolymer mortar *Manuscript Click here to view linked References 2 IntroductionThere are many environmental issues associated with the production of Ordinary Portland cement (OPC), such as consumption of 5% of natural resources, and generation of 5-7 % of total global anthropogenic carbon dioxide emissions [1][2][3][4]. This has led to an urgent need for the development of alternative materials that may provide technically viable alternative solutions to conventional cementitious concrete, with more favourable environmental credentials. Geopolymer concrete manufacture is one of the most promising techniques which has been developed in the last few years. Utilization of geopolymer materials can reduce 80% of greenhouse gas emissions associated with material production, and overcome issues related to cement production and unregulated disposal of industrial materials by recycling these materials in geopolymer manufacture [5][6][7].Geopolymers are inorganic by-product materials, rich in silicon (Si) and aluminium Five different mixtures of geopolymer mortar proportions were examined with various ratios of GGBS to total binder (10%, 20%, 30%, 40% and 50 %, Table 2). Based on preliminary experimental studies undertaken during the current project, the optimum mix design (in terms of mechanical strength and workability) was achieved using water, alkaline activator...

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Section: Introductionmentioning

confidence: 99%

Development of geopolymer mortar under ambient temperature for in situ applications

Al-Majidi

Λαμπρόπουλος

Cundy

et al. 2016

Construction and Building Materials

305

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“…Calcium sulfoaluminate (CSA) cements are receiving increasing attention since their manufacture produces much less CO 2 than ordinary Portland cement (OPC) [1][2][3][4][5]. In addition, they show interesting properties such as high early-age strengths [6][7][8], short setting times, impermeability [9,10], sulfate and chloride corrosion resistance and low alkalinity.…”

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

171

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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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“…Moreover, it needs vast amounts of energy to grind the raw mixtures and the final products. The combined decarbonation, thermal and electrical-power CO 2 emissions may total as much as 0.97 tons of CO 2 per average ton of Portland Cement (OPC) produced. Thus, the cement industry contributes around 6% of all CO 2 anthropogenic emissions [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…The combined decarbonation, thermal and electrical-power CO 2 emissions may total as much as 0.97 tons of CO 2 per average ton of Portland Cement (OPC) produced. Thus, the cement industry contributes around 6% of all CO 2 anthropogenic emissions [1,2]. Belite-rich cements were proposed as environmentally friendly materials [3,4].…”

Section: Introductionmentioning

confidence: 99%