Quick monitoring of pozzolanic reactivity of waste ashes

Sinthaworn, Suppachai; Nimityongskul, Pichai

doi:10.1016/j.wasman.2008.11.010

Cited by 41 publications

(18 citation statements)

References 17 publications

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“…Sintharworn et al [7] studied pozzolanic activity by measuring the electrical conductivity of various materials, such as silica fume, metakaolin and rice husk ash with aqueous suspensions at a temperature of 80 °C. They performed this study with aqueous suspensions by mixing ordinary Portland cement with the specific pozzolanic material of study.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

et al. 2014

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The pozzolanic activity of the spent catalyst produced by fluid catalytic cracking (FCC) has been studied by various methods in recent years. However, no quick and easy method has been reported for this activity based on the associated studies. In this work, the pozzolanic activity of a spent catalyst was investigated by measuring its electrical conductivity in aqueous suspensions of pozzolan/calcium hydroxide. The behavior of the FCC catalyst residue was compared to that of reactive and inert materials of similar chemical compositions. Further, the influence of temperature on the suspension was studied, and also, a new method was proposed in which the pozzolan/calcium hydroxide ratio was varied (with the initial presence of solid Ca(OH)2 in the system). It was concluded that the method is effective, fast and simple for evaluating the high reactivity of the catalyst. Therefore, this method is an alternative for the evaluation of the reactivity of pozzolanic materials.

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Section: Introductionmentioning

confidence: 99%

Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

et al. 2014

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“…Natural calcined and artificial pozzolans, which need chemical and mineralogical changes to exhibit their pozzolanic activity, can be obtained from sources such as blast furnace slag, industrial waste generated in the production of iron, the ash of organic materials, and agricultural waste. Recently, studies have shown that artificial and natural pozzolans can have good pozzolanic characteristics (Lima Souza and Dal Molin 2005;Mathur 2005;MartinezRamirez et al 2006;Sinthaworn and Nimityongskul 2009;Karade 2010;Amigó et al 2011;Rosell-Lam et al 2011;Villar Cociña et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Barley Straw Ash: Pozzolanic Activity and Comparison with other Natural and Artificial Pozzolans from México

et al. 2015

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“…After the mixture was clear, it was carefully poured, and kept the clear solution (without dregs) in a sealed container to protect against carbonation. Evaluation of pozzolanic activity was performed using 200 mL of OPC solution and 1 g of pozzolan under continuous stirring at 80 °C during 24 h (14).…”

Section: Introductionmentioning

confidence: 99%

New method to assess the pozzolanic reactivity of mineral admixtures by means of pH and electrical conductivity measurements in lime:pozzolan suspensions

Tashima¹,

Soriano²,

Monzó³

et al. 2014

Mater. construcc.

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A very simple method based on electrical conductivity and pH measurements was proposed for assessing reactivity of pozzolans. Calcium hydroxide:pozzolan water suspensions were monitored by means of measurements of electrical conductivity and pH values. In these suspensions, Ca(OH) 2 in solid state was initially present, being them, thus, saturated in this reagent. Three testing temperatures were selected (40, 50 and 60 °C). In the experiments carried out, calcium hydroxide was suspended in deionized water for yielding a lime saturated suspension. The addition of siliceous pozzolan (two types of rice husk ash RHA and two types of densified silica fume DSF were tested) to the saturated lime suspension can produce the unsaturation of the system, depending on the testing time, testing temperature and reactivity of pozzolan. When unsaturation was reached, the loss of electrical conductivity was higher than 30% and the variation of pH was higher than 0.15 units. These threshold values were selected for characterizing the reactivity of pozzolans by means of a proposed template, classifying the pozzolan in three different reactivity levels. RESUMEN:Nuevo método para evaluar la reactividad puzolánica de adiciones minerales por medio de medidas de pH y conductividad eléctrica en suspensiones cal:puzolana. En este trabajo se propone un método simple basado en medidas de conductividad eléctrica y pH. Se determinaron los valores de conductividad eléctrica y pH de suspensiones acuosas de hidróxido cálcico:puzolana. En las suspensiones, había inicialmente Ca(OH) 2 en estado sólido, de manera que dichas suspensiones estaban, por tanto, saturadas respecto a ese reactivo. Se seleccionaron tres temperaturas de trabajo (40, 50 and 60 °C). En las experiencias, el hidróxido cálcico fue mezclado con agua desionizada, generando una suspensión saturada en cal. La adición de puzolana silícea (se ensayaron dos tipos de ceniza de cáscara de arroz y dos tipos de humo de sílice densificado) a la suspensión saturada de cal puede producir la insaturación del sistema, dependiendo del tiempo, temperatura y reactividad de la puzolana. Cuando se alcanza la insaturación, la pérdida de conductividad eléctrica fue mayor a 30% y la variación de pH fue mayor que 0.15 unidades. Estos valores umbral fueron seleccionados para caracterizar la reactividad de las puzolanas por medio de una plantilla propuesta al efecto, clasificando la puzolana en tres niveles de reactividad diferentes.

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Quick monitoring of pozzolanic reactivity of waste ashes

Cited by 41 publications

References 17 publications

Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

Barley Straw Ash: Pozzolanic Activity and Comparison with other Natural and Artificial Pozzolans from México

New method to assess the pozzolanic reactivity of mineral admixtures by means of pH and electrical conductivity measurements in lime:pozzolan suspensions

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