Utilization of citro- and desulphogypsum as set retarders in Portland cement

Özkul, M. Hulusi

doi:10.1016/s0008-8846(00)00409-9

Cited by 48 publications

(13 citation statements)

References 4 publications

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“…Quando somente é utilizado gesso FGD na argamassa, a resistência diminui com respeito a os casos em que se utilizou uma mistura gesso natural/gesso FGD, mas segue sendo maior em comparação à resistência à compressão atingida para aquelas somente com gesso natural. Resultados reportados na Turquia [5] mostraram também para todas as idades de cura, diminuição na resistência à compressão com argamassas preparadas somente com 4% de gesso FGD com respeito aos resultados obtidos com argamassas preparadas com 4% de gesso natural.…”

Section: Avaliação Das Argamassasunclassified

“…No entanto, a aglomeração aumentou a resistência do cimento depois dos 28 dias. Por outro lado, do acordo a Ozkul [5] a mistura com citrogesso deu resultados satisfatórios em todas as idades, exceto sob a forma de pó com a idade de 3 dias, que exibiu uma resistência à compressão menor do que a referência. Na dessulfurização de gases de combustão é gerado, como resíduo, grandes quantidades de gesso FGD e sua disposição direta em aterros por longos períodos não é a solução mais adequada, por causa dos custos envolvidos e das rigorosas restrições impostas pelas normas ambientais.…”

Section: Introductionunclassified

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Viabilidade Técnica Para Uso De Gesso FGD Como Aditivo Retardador Do Tempo De Pega Em Cimento Portland

Caillahua¹,

Moura²

2014

ABM Proceedings

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ResumoNo presente estudo o gesso FGD (flue gas desulfurization) foi avaliado como aditivo retardador do tempo de pega, substituindo o gesso natural na fabricação do cimento Portland (CP II E-32). Os resultados da caracterização físico-química e morfológica do gesso natural e do gesso FGD identificaram um material de alta pureza, sulfato de cálcio di-hidratado para o gesso natural e a presença, principalmente, de bassanita (CaSO4.0,6H2O) e hannebachite (CaSO3.0,5H2O) com baixas concentrações de impurezas no gesso FGD. Baseado nos resultados, o gesso FGD é uma alternativa adequada para substituir o gesso natural. O tempo de pega mostrou cerca de uma hora de retardo em comparação com gesso natural e seu efeito sobre a resistência à compressão para as amostras de 3, 7 e 28 dias dependem da composição das misturas, atingindo um valor máximo para a argamassa com 2,1% de gesso FGD e 1,4% de gesso natural. Seguindo a norma ABNT NBR 10004:2004 o resíduo é classificado como não perigoso e não inerte. Palavras-chave: Gesso FGD; Dessulfurização de gases; Sulfato de cálcio hemihidrato; Cimento Portland. TECHNICAL FEASIBILITY FOR THE USE OF FGD GYPSUM AS AN ADDITIVE SETTING TIME RETARDER FOR PORTLAND CEMENT AbstractIn the present study the FGD (flue gas desulfurization) gypsum was evaluated as setting retarder to replace the natural gypsum in the production of Portland cement (CP II E-32). The results of physical-chemistry and morphological characterization of both products, natural and FGD gypsum showed a material of high purity, calcium sulfate dehydrate for natural gypsum, and the presence of bassanite (CASO4.0.6H2O) and hannebachite (CaSO3.0,5H2O) with low concentrations of impurities for FGD gypsum. Based the results, the FGD gypsum is a suitable alternative to replace natural gypsum. The setting time with FGD gypsum showed about 1 hour delay compared with natural gypsum and its effect on compressive strength, for samples of 3, 7 and 28 days, depend the composition of the mixtures, reaching the maximum value for the mixture of 1,4 weight% natural gypsum and 2,1 weight% FGD gypsum. Following the standard ABNT NBR 10004:2004 the residue was classified as a non-hazardous and non-inert.

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Section: Avaliação Das Argamassasunclassified

Section: Introductionunclassified

Viabilidade Técnica Para Uso De Gesso FGD Como Aditivo Retardador Do Tempo De Pega Em Cimento Portland

Caillahua¹,

Moura²

2014

ABM Proceedings

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“…bentonite, hydrofuge agents), drying controllers, setting retarders and rheology modifiers (cellulose-derived materials, sugars, phosphates) [6,7]. Setting retarding agents are usually water soluble and act on the chemistry (solubility and dissolution rate) of the hydrating cement phases [8,9]. To this aim, sodium bentonite is often used, as it provides the adequate rheological properties (plasticity, workability and thixotropy) associated with montmorilonite [10].…”

Section: Introductionmentioning

confidence: 99%

Effects of potable water filtration sludge on the rheological behaviour of one-coat plastering mortars

Raupp-Pereira¹,

Silva²,

Segadães³

et al. 2007

Journal of Materials Processing Technology

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“…(Aïtcin 2000). Gypsum, which can be waste such as Flue-Gas Desulfurization (FGD) gypsum or a natural material (Ozkul 2000) is added as a set controller (Marceau et al 2006). Cement also contains supplementary cementitious materials (SCM) (Pickering et al 1985;American Concrete Institute 2000C09 Committee 2004C09 Committee , 2010C09 Committee , 2014O'Brien et al 2009;Yang et al 2014) that contribute to the properties of hardened concrete through hydraulic or pozzolanic activity.…”

Section: Discussionmentioning

confidence: 99%

Concrete water footprint: a streamlined methodology

Vergara¹,

Lisbeth²

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Water is the most used substance in the world, followed by concrete. Water scarcity is nowadays more common due to concentrated population growth and climate change. Concrete demand is ~15 billion m 3 per year fulfilling the need for more and better housing and infrastructure for a growing and wealthier population. Since no other material could fulfil this demand, concrete needs to be produced in a sustainable way, minimizing environmental loads such as water consumption. The water footprint is a tool that measures water use over a products' life cycle and estimates its potential environmental impacts. Despite the growing concern on water, the existing water footprint methodologies are too complex and require large amounts of data. This study develops a streamlined water footprint methodology for concrete production, simple enough to be useful to the industry and robust enough to be environmentally meaningful. An extensive study on existing water footprint methodologies have been conducted. Then a streamlined methodology was proposed focused on the water flows that are more relevant in concrete production including water quantity and quality letting to meaningful results with less data. Typical water inventory includes the batch water (150-200 H kg/m 3), dust control (500-1500 H kg/day), truck washing (13-500 H kg/m 3), cement production (0.185-1.333 H kg/kg) and aggregates production (0.116-2.0 H kg/kg). Regarding water quality, the most critical flows-Zinc, Lead, Nitrate, Nitrogen oxides and Sulfur dioxide-were identified based on the contribution of these flows to the potential environmental impacts, the control or influence that the concrete producer has on the activities were these flows appear and the feasibility to measure these flows on site. Concrete water footprint varies due to mix design, technological routes, location and choice of impact assessment method. The results are of interest to the research community as well as to the stakeholders of the cement and concrete industries and a contribution to sustainable construction since study of water footprint is fundamental to improve water efficiency.

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Utilization of citro- and desulphogypsum as set retarders in Portland cement

Cited by 48 publications

References 4 publications

Viabilidade Técnica Para Uso De Gesso FGD Como Aditivo Retardador Do Tempo De Pega Em Cimento Portland

Viabilidade Técnica Para Uso De Gesso FGD Como Aditivo Retardador Do Tempo De Pega Em Cimento Portland

Effects of potable water filtration sludge on the rheological behaviour of one-coat plastering mortars

Concrete water footprint: a streamlined methodology

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