Effect of thermal treatment on pozzolanic activity of excavated waste clays

Yanguatin, Hernan; Ramírez, Jorge H; Tironi, Alejandra; Tobón, Jorge Iván

doi:10.1016/j.conbuildmat.2019.03.300

Cited by 50 publications

(29 citation statements)

References 36 publications

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“…It is, however, interesting to note that the clays with poor kaolinite content or that were found to be mixed with other materials presented good SAI values. This was also evidenced by Yanguatin et al, who evaluated the pozzolanic activity of excavated waste clays, and found satisfactory results that indicated that the best pozzolanic activity was found in materials with high kaolinite content [16]. Uchima et al obtained good results that showed pozzolanic activity in biomass and kaolinitic clay [17].…”

Section: Characterizationmentioning

confidence: 69%

“…On the other hand, when the correlations between SAI and the characterization variables were evaluated, it was found that the only characterization that had a relationship higher than 75% was kaolinite content. It is important to note, however, that although many researchers have studied the relationship between SAI and kaolinite [16,3,6,17], it was also relevant to the present study, although these kinds of materials showed low values of kaolinite and had a high quartz content, which could suggest that these kinds of materials' pozzolanic activity are related to the clay content more than the kaolinite content, which has been suggested by Msinjili et al, referring to the pozzolanic activity of illite clays [18].…”

Section: Characterizationmentioning

confidence: 99%

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Cement production with pozzolans from residual tropical soils formed from paragneiss with a high silicon oxide content

Torres¹,

Saldarriaga

Tobón

2020

DYNA

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The manufacture of cement demands a lot of energy and gives off large amounts of CO2. Calcined clays need less energy and emit water instead of CO2, which has drawn attention to them, especially those rich in kaolinite. However, their use has been discouraged due to their location and high market price. Hence, the present study focuses on calcined clays with a low kaolinite content, specifically those derivedfrom paragneiss. In Colombia they are located in weathering horizons with depths of up to 40 meters. The results showed contents of 20%Al2O3, less than 14% Fe2O3, more than 60% SiO2, less than 40% kaolinite, 20% illite and more than 30% quartz. Calcined at 750 °C, they were used in mortars, obtaining SAI values of between 80 and 100% after 28 days, which, added to the results of Frattini tests, show that their use as a supplementary cementing material is feasible.

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Section: Characterizationmentioning

confidence: 69%

Section: Characterizationmentioning

confidence: 99%

Cement production with pozzolans from residual tropical soils formed from paragneiss with a high silicon oxide content

Torres¹,

Saldarriaga

Tobón

2020

DYNA

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“…Halloysite is a clay with identical chemical composition of kaolinite, except that halloysite may have as many as two molecules of H 2 O, as interlayer water [ 28 ]. Since kaolinitic waste clays have already been tested for their pozzolanic activity after thermal treatment [ 29 ], we also proceeded with calcination of the as-received halloysitic-illitic clayey by-product. It has already been reported that the presence of kaolinite and spheroidal halloysite exerts great influence at early ages, while tubular halloysite has a greater influence in the pozzolanic activity and the compressive strength of mortars at later ages [ 30 ].…”

Section: Introductionmentioning

confidence: 99%

Mine Clay Washing Residues as a Source for Alkali-Activated Binders

Sgarlata

Formia²,

Siligardi

et al. 2021

Materials

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The aim of this paper is to promote the use of mine clay washing residues for the preparation of alkali activated materials (AAMs). In particular, the influence of the calcination temperature of the clayey by-product on the geopolymerization process was investigated in terms of chemical stability and durability in water. The halloysitic clay, a mining by-product, has been used after calcination and mixed with an alkaline solution to form alkali activated binders. Attention was focused on the influence of the clay’s calcination treatment (450–500–600 °C) on the geopolymers’ microstructure of samples, remaining in the lower limit indicated by the literature for kaolinite or illite calcination. The mixtures of clay and alkali activators (NaOH 8M and Na-silicate) were cured at room temperature for 28 days. The influence of solid to liquid ratio in the mix formulation was also tested in terms of chemical stability measuring the pH and the ionic conductivity of the eluate after 24-h immersion time in water. The results reported values of ionic conductivity higher for samples made with untreated clay or with low temperature of calcination (≥756 mS/m) compared with values of samples made with calcined clay (292 mS/m). This result suggests that without a proper calcination of the as-received clay it was not possible to obtain 25 °C-consolidated AAMs with good chemical stability and dense microstructure. The measures of integrity test, pH, and ionic conductivity in water confirmed that the best sample is made with calcined clay at 600 °C, being similar (53% higher ionic conductivity of the eluate) or equal (integrity test and pH) to values recorded for the metakaolin-based geopolymer considered the reference material. These results were reflected in term of reticulation and morphology of samples through the analysis with scanning electron microscope (SEM) and X-ray diffraction (XRD), which show a dense and homogeneous microstructure predominantly amorphous with minor amounts of quartz, halloysite, and illite crystalline phases. Special attention was dedicated to this by-product to promote its use, given that kaolinite (and metakaolin), as primary mineral product, has a strong impact on the environment. The results obtained led us to consider this halloysite clay very interesting as an aluminosilicate precursor, and extensively deepening its properties and reactivity for the alkaline activation. In fact, the heart of this work is to study the possibility of reusing this by-product of an industrial process to obtain more sustainable high-performance binders.

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“…The advantage of implementing a blended cement with a supplementary cementitious material (SCM) generally consist in the improvement of the mechanical properties, in the durability of concrete (resistance of sulfates attack, leaching, freeze/thaw, etc), in the decrease of porosity and permeability, in the improve of the adherence of the paste or cement, in the least heat released during hydration process and in the reduction of the amount of cement per unit volume (which leads to energy and economic savings) 7‐15 …”

Section: Introductionmentioning

confidence: 99%

Valorization of waste from sand wash muds of an aggregates plant: Evaluation as a supplementary cementitious material

Baena

Cabrera-Poloche

Tobón

et al. 2020

Int J Applied Ceramic Tech

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The reuse and reincorporation of waste generated in the production processes are becoming increasingly important in the world, due to the double effect that it has in terms of sustainability. The first one is the environmental factor, since the impact generated is reduced by reducing the amount of wastes. The second one is the financial factor, since new products are developed that companies did not initially have, generating financial profitability. Therefore, this research evaluates the possible reuse of waste from gravel and sand wash mud of an aggregate plant as a supplementary cementitious material (SCM) after being thermally activated, seeking to promote the circular economy in the construction materials sector. The physical, chemical, and mineralogical characterization of the waste is presented and its pozzolanic activity was evaluated by means of the SAI-strength activity index. It was found that despite its low content of clay minerals, the thermally activated waste had very good performance as SCM with SAI between 81 and 106 with a tendency to increase with the age of cure. Showing that this can be a very promising potential use for this kind of waste.

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Effect of thermal treatment on pozzolanic activity of excavated waste clays

Cited by 50 publications

References 36 publications

Cement production with pozzolans from residual tropical soils formed from paragneiss with a high silicon oxide content

Cement production with pozzolans from residual tropical soils formed from paragneiss with a high silicon oxide content

Mine Clay Washing Residues as a Source for Alkali-Activated Binders

Valorization of waste from sand wash muds of an aggregates plant: Evaluation as a supplementary cementitious material

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