Rapid evaluation of pozzolanic activity of natural products by conductivity measurement

Luxán, María Pilar de; Madruga, F.; Saavedra, J.

doi:10.1016/0008-8846(89)90066-5

Cited by 278 publications

(212 citation statements)

References 3 publications

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“…As shown in Table 5, the median variation of conductivity after 2 min of IN-SCSA was 1.07 mS cm -1 , which allowed classifying this ash as low reactive, in accordance to the Luxan's criterion. 26 On the other hand, both WW-SCSA and HL-SCSA were classified as good pozzolanic materials, with variations of 2.89 and 5.80 mS cm -1 , respectively. In this case, the 2 min-decrease was more significantly intense in HL-SCSA.…”

Section: Pozzolanic Activity Of Ashesmentioning

confidence: 97%

“…The first was the electrical conductivity method proposed by Lúxan et al, 26 where the variation of the electrical conductivity of a saturated solution of calcium hydroxide (96% purity, Vetec) with 1.75 g of the sample, with constant agitation at 40 ± 1 °C, was continuously monitored over 20 min using a portable conductivity meter (Alfakit 230). The conductivity test was conducted three times for each ash.…”

Section: Characterization Of Scsasmentioning

confidence: 99%

“…The conductivity test was conducted three times for each ash. Lúxan et al 26 proposed a classification criterion of material with respect to its pozzolanic property based on the variation of conductivity (ΔC) 2 min into the test (Table 1). In this case, the greater the change in the conductivity of solution added with the sample, the more pozzolanic the sample was.…”

Section: Characterization Of Scsasmentioning

confidence: 99%

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Study on the pozzolanic activity of sugar cane straw ash produced using different pretreatments

Cordeiro¹,

Vieira²,

Lopes³

2017

Quim. Nova

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This work systematically describes a laboratory study on different pretreatments of sugar cane straw to produce pozzolanic ash. Two procedures were used to accelerate the hydrolysis of celluloses and hemicelluloses and remove metallic impurities present in significant levels in sugar cane straw: hot water washing and acid leaching. Proximate analysis by thermogravimetry was carried out to cover volatile matter, fixed carbon, and ash content of the different straws. Detailed measurements of X-ray diffraction, oxide percentages, loss on ignition, and BET specific surface area were performed to compare hot water washed, acid leached, and nonpretreated ashes, after controlled processes of burning and grinding. The pozzolanic activity of the ashes was evaluated from the modified Chapelle and electrical conductivity methods. The results revealed that ashes with a high content of amorphous silica were produced, in spite of the straw pretreatments. However, both straw pretreatments induced a significant increase in pozzolanic activity, mainly associated with the removal of impurities, especially CaO, SO 3 , K 2 O, and carbon compounds. The effect of the hot water washing treatment was relatively small in relation to the acid leaching, but the hot washed ash was significantly more pozzolanic than non-treated ash.

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Section: Pozzolanic Activity Of Ashesmentioning

confidence: 97%

Section: Characterization Of Scsasmentioning

confidence: 99%

Section: Characterization Of Scsasmentioning

confidence: 99%

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Study on the pozzolanic activity of sugar cane straw ash produced using different pretreatments

Cordeiro¹,

Vieira²,

Lopes³

2017

Quim. Nova

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“…Pozzolanic activity measurements are carried out on the fine fraction of the powder ( < 45 mm). The results as shown in Table 1 indicates that the fine aggregates have the pozzolanic activity values well over 1.2 mS/cm above which is accepted as good pozzolanacity [16]. Therefore, deterioration of type 2 plaster cannot result from differences in the amount of brick powder, their pozzolanacity, and lime contents.…”

Section: Discussionmentioning

confidence: 95%

“…Pozzolanic activities of the brick powder (less than 45 mm) were determined by mixing them into saturated calcium hydroxide solution and by measuring the differences in electrical conductivity [16].…”

Section: Methodsmentioning

confidence: 99%

Ettringite formation in historic bath brick–lime plasters

Böke

Akkurt

2003

Cement and Concrete Research

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Two types of historic hydraulic brick -lime plasters from a selected Ottoman bath are examined to characterize their technology and the appropriateness of their use in bath. The first type of plaster is original and structurally sound, while the historic repair plaster is the second type and is found to have deteriorated despite being exposed to the same environment. This difference is investigated by comparing their raw material compositions and the pozzolanic activities of the brick powders used in the plasters. Although these results showed no significant differences, ettringite crystals are detected in the historic repair ones by XRD, FTIR, and SEM-EDS analysis. The repair plaster may have lost its integrity owing to the expansion generated by the growth of ettringite crystals in the plaster. In this study, the ettringite formation is discussed in relation to hydration reaction products of lime -brick plasters, possible sources of gypsum, and the climatic conditions of historic bath building. D

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