Alkali activated ceramic waste with or without two different calcium sources

Zedan, Sayieda R.; Mohamed, Maha R.; Ahmed, Doaa; Mohammed, Aya H.

doi:10.12989/amr.2015.4.3.133

Cited by 7 publications

(7 citation statements)

References 23 publications

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“…As explained by Dzunuzovic et al [30], this displacement denotes the formation of bigger amounts of amorphous binding gel due to alkali-activation reactions. These results fall in line with those previously reported by Zedan et al [1], who also observed that the amorphous content in alkali-activated ceramic/BFS blends increased with the replacement percentage of the ceramic material with BFS.…”

Section: X-ray Diffraction (Xrd) Studiessupporting

confidence: 93%

“…This shift toward higher temperatures was generally accompanied by higher mass loss values and, in agreement with Moraes et al [32], both indicate changes in the gel formed during the activation process, which denotes the formation of phases with strongly bonded water. These results also coincide with those previously reported by Zedan et al [1], who observed an increase in the chemically bonded water with rising BFS contents in alkali-activated ceramic waste/BFS blends (10 and 30 wt % replacements). The higher recorded mass loss with increasing BFS contents well agrees with the positive evolution of the compressive strength results reported in Figure 4, and also with the higher amorphous contents in the binding matrix denoted by the XRD spectra ( Figures 5 and 6).…”

Section: Thermogravimetric Analysessupporting

confidence: 93%

“…This denotes a higher amorphous gel content and is in tune with the improved compressive strength results reported in Figure 4. [1], who also observed that the amorphous content in alkali-activated ceramic/BFS blends increased with the replacement percentage of the ceramic material with BFS. A low-intensity band centered at 29.5 2θ degrees emerged in the spectra of the pastes that contained 30 wt % or 50 wt % BFS.…”

Section: X-ray Diffraction (Xrd) Studiesmentioning

confidence: 88%

“…Although its properties and behavior are well-known, the greenhouse gases emitted during its production, together with the natural resources used, have motivated new more eco-efficient binders, such as alkali-activated cements, to be developed. As explained by Zedan et al [1], alkali-activated binders may be classified into two main types: low-calcium systems, which generally require applying temperature to set; and calcium-based binders, which usually harden at room temperature. While N-A-S-H gel mainly forms in the former, the activation of high-calcium systems principally brings about C-A-S-H gel [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…However, addition of Ca(OH) 2 and applying temperature to cure samples proved essential to successfully activate this ceramic waste material, which limited its use mainly to prefabricated applications. In order to improve the properties of alkali-activated binders developed using a single material as a precursor, several studies have lately combined low-calcium precursors, like CSW, with different sources of calcium and reactive Al 2 O 3 , such as BFS [1,2,[19][20][21][22][23], FA [6], calcium aluminate cement (CAC) or Portland cement (PC) [24,25]. observed that the heat of reaction in an alkali-activated natural pozzolan/BFS binary cement increased with BFS addition, which accelerated the kinetics of the process and, consequently, favored the activation of the pozzolan at room temperature, as well as strength development.…”

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confidence: 99%

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The Compressive Strength and Microstructure of Alkali-Activated Binary Cements Developed by Combining Ceramic Sanitaryware with Fly Ash or Blast Furnace Slag

et al. 2018

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The properties of a binder developed by the alkali-activation of a single waste material can improve when it is blended with different industrial by-products. This research aimed to investigate the influence of blast furnace slag (BFS) and fly ash (FA) (0-50 wt %) on the microstructure and compressive strength of alkali-activated ceramic sanitaryware (CSW). 4 wt % Ca(OH) 2 was added to the CSW/FA blended samples and, given the high calcium content of BFS, the influence of BFS was analyzed with and without adding Ca(OH) 2 . Mortars were used to assess the compressive strength of the blended cements, and their microstructure was investigated in pastes by X-ray diffraction, thermogravimetry, and field emission scanning electron microscopy. All the samples were cured at 20 • C for 28 and 90 days and at 65 • C for 7 days. The results show that the partial replacement of CSW with BFS or FA allowed CSW to be activated at 20 • C. The CSW/BFS systems exhibited better mechanical properties than the CSW/FA blended mortars, so that maximum strength values of 54.3 MPa and 29.4 MPa were obtained in the samples prepared with 50 wt % BFS and FA, respectively, cured at 20 • C for 90 days. fuel gases in coal thermoelectric plants [5] and, according to [6,7], it is estimated that approximately 750-780 million tons are produced yearly. Granulated BFS is formed by rapidly cooling melted slag during iron production [8]. As reported by the World Steel Association [9], 1629.6 million tons of steel were produced worldwide in 2016, of which 74.3% are made in blast furnaces and the remaining 25.7% in electric furnaces. Consequently, approximately 300-360 million tons of iron slag were produced globally in blast furnaces in 2016, and 160-240 million tons of steel slag were generated in electric arc and basic oxygen furnaces [10].In the last few decades, the use of different silico aluminate waste materials as a precursor in alkali-activated binders has been widely investigated [11,12]. Reusing waste materials as a precursor positively contributes to sustainable development because it limits the mining of natural resources, reduces the visual impact caused by accumulated waste, and diminishes the emissions associated with Portland cement manufacture [13,14]. Ceramic materials are a very interesting option to be explored to develop alkali-activated cements as they are chemically inert and present a long biodegradation period (up to 4000 years) [15]. Among them, ceramic sanitaryware waste (CSW) units are expected to present quite a homogeneous chemical and mineralogical composition since they are generally sintered within a narrow range of calcination temperatures (1200-1280 • C [16]). Moreover, CSW units (i.e., washbasins, lavatories, or bidets) can be easily separated from construction and demolition waste (CDW), which implies that they will present fewer impurities, such as gypsum or Portland cement. As reported by Baraldi [17], nearly 349.3 million CSW units were globally produced in 2014, of which almost 12% (41.6 million) was manufacture...

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Section: X-ray Diffraction (Xrd) Studiessupporting

confidence: 93%

Section: Thermogravimetric Analysessupporting

confidence: 93%

Section: X-ray Diffraction (Xrd) Studiesmentioning

confidence: 88%