Pozzolanic activity of mechanochemically and thermally activated coal-series kaolin in cement-based materials

2021 ◽  
Vol 299 ◽  
pp. 123972
Author(s):  
Shukai Cheng ◽  
Keyu Ge ◽  
Tao Sun ◽  
Zhonghe Shui ◽  
Xuyong Chen ◽  
...  
Keyword(s):  
Pozzolanic Activity ◽  
Thermally Activated ◽  
Activated Coal ◽  
Cement Based Materials

scholarly journals Evaluating the Effect of Calcination and Grinding of Corn Stalk Ash on Pozzolanic Potential for Sustainable Cement-Based Materials

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shazim Ali Memon ◽  
Saba Khan ◽  
Israr Wahid ◽  
Yekaterina Shestakova ◽  
Muhammad Ashraf
Keyword(s):  
Activity Index ◽  
Pozzolanic Activity ◽  
Second Phase ◽  
Corn Stalk ◽  
Cement Concrete ◽  
Carbon Particles ◽  
Cement Based Materials ◽  
Two Phases ◽  
Pozzolanic Properties ◽  
Ash Disposal

In developing countries, one of the usual practices is the uncontrolled, open burning of corn stalk (CS) or its utilization as a fuel. It is known that the ash obtained under uncontrolled burning conditions constitutes blackish and unburnt carbon particles as well as whitish and grayish particles (representing crystallization of silica) due to over burning. However, controlling the burning process can improve the quality of ash produced to effectively use it in cement-based materials. Hence, this research was aimed at exploring the pozzolanic properties of corn stalk ash upon calcination and grinding, for it to be used in the manufacturing of sustainable cement-based materials. In order to obtain a suitable corn stalk ash (CSA), which can be used in cement/concrete, a research investigation consisted of two phases. In the first phase, calcination was carried out at 400°C, 500°C, 600°C, 700°C, and 800°C for 2 hours. The tests applied on the resulting ashes were weight loss, XRD, pozzolanic activity index (PAI), Chapelle, Fratini, and consistency. From XRD spectra, it was found that, at lower temperatures, silica remained amorphous, while it crystallized at higher temperature. Ash combusted at a temperature of 500°C possessed largest pozzolanic activity of 96.8%, had a Fratini CaO reduction of 93.2%, and Chapelle activity of 856.3 mg/g. Thus, 500°C was chosen as an optimum calcination temperature. In the second phase, the ash produced at 500°C was grinded for durations of 30, 60, 120, and 240 minutes to ascertain the optimum grinding times. Resulting ashes were examined for hydrometer analysis, Blaine fineness, Chapelle activity, and pozzolanic activity. Experiment outcomes revealed a direct relationship between values of Blaine fineness, surface area, Chapelle activity, PAI, and grinding duration. It was concluded that CSA can be used as a pozzolan, and thus, its utilization in cement/concrete would solve ash disposal problems and aid in production of eco-friendly cement/concrete.

Assessment of pozzolanic activity of thermally activated clay and its impact on strength development in cement mortar

RSC Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 6079-6084 ◽  
Author(s):  
Noor-ul- Amin ◽  
Sultan Alam ◽  
Saeed gul
Keyword(s):  
Cement Mortar ◽  
Pozzolanic Activity ◽  
Strength Development ◽  
Thermally Activated ◽  
Different Temperatures ◽  
Kaolinitic Clay

Natural kaolinitic clay from Khyber Pakhtoonkhwa, Pakistan was thermally activated at different temperatures and its pozzolanic behavior was studied.

scholarly journals Effects of Red Mud Addition in the Microstructure, Durability and Mechanical Performance of Cement Mortars

2019 ◽  
Vol 9 (5) ◽  
pp. 984 ◽  
Author(s):  
José Ortega ◽  
Marta Cabeza ◽  
Antonio Tenza-Abril ◽  
Teresa Real-Herraiz ◽  
Miguel Climent ◽  
...  
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Mechanical Performance ◽  
Network Evolution ◽  
Cement Industry ◽  
Pozzolanic Activity ◽  
Great Effort ◽  
Chloride Ingress ◽  
Cement Mortars ◽  
Cement Based Materials

Recently, there has been a great effort to incorporate industrial waste into cement-based materials to reach a more sustainable cement industry. In this regard, the Bayer process of obtaining alumina from bauxite generates huge amounts of waste called red mud. Few research articles have pointed out the possibility that red mud has pozzolanic activity. In view of that, the objective of this research is to analyse the short-term effects in the pore structure, mechanical performance and durability of mortars which incorporate up to 20% of red mud as a clinker replacement. As a reference, ordinary Portland cement and fly ash Portland cement mortars were also studied. The microstructure was characterised through mercury intrusion porosimetry and non-destructive impedance spectroscopy, which has not previously been used for studying the pore network evolution of red mud cement-based materials. The possible pozzolanic activity of red mud has been checked using differential scanning calorimetry. The non-steady state chloride migration coefficient and the mechanical properties were studied too. According to the results obtained, the addition of red mud entailed a greater microstructure refinement of the mortar, did not worsen the resistance against chloride ingress and reduced the compressive strength compared to control binders.

Pozzolanic activity of mechanochemically and thermally activated kaolins in cement

2015 ◽  
Vol 77 ◽  
pp. 47-59 ◽  
Author(s):  
Alireza Souri ◽  
Hadi Kazemi-Kamyab ◽  
Ruben Snellings ◽  
Rahim Naghizadeh ◽  
Farhad Golestani-Fard ◽  
...  
Keyword(s):  
Pozzolanic Activity ◽  
Thermally Activated

scholarly journals Correction: Assessment of pozzolanic activity of thermally activated clay and its impact on strength development in cement mortar

RSC Advances ◽  
2015 ◽  
Vol 5 (14) ◽  
pp. 10680-10680 ◽  
Author(s):  
Noor-ul- Amin ◽  
Sultan Alam ◽  
Saeed Gul
Keyword(s):  
Cement Mortar ◽  
Pozzolanic Activity ◽  
Strength Development ◽  
Thermally Activated

Correction for ‘Assessment of pozzolanic activity of thermally activated clay and its impact on strength development in cement mortar’ by Noor-ul- Amin et al., RSC Adv., 2015, 5, 6079–6084.

Properties of Cement-Based Materials Containing Melting Incinerator Bottom Ash

2011 ◽  
Vol 250-253 ◽  
pp. 834-838 ◽  
Author(s):  
An Cheng ◽  
Hui Mi Hsu ◽  
Sao Jeng Chao ◽  
Wei Ting Lin ◽  
Hao Hsien Chen ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Particle Size ◽  
Compressive Strength ◽  
Portland Cement ◽  
Bottom Ash ◽  
Pozzolanic Activity ◽  
Unit Weight ◽  
Maximum Particle Size ◽  
Cement Based Materials ◽  
Maximum Particle

This paper presents an experimental investigation on the effect of incinerator bottom ash (IBA) fineness and the cooled process of molten IBA on fresh mortar properties and compressive strength of hardened mortars. IBA with two finenesses, an original IBA, and a pulverizing incinerator bottom ash (PIBA) powder, with maximum particle size of 4.75 and 0.074 mm respectively were used to partially replace sand and Portland cement at 0%, 10%, 20%, 30%, and 40% by weight. The pozzolanic activity characteristics of powder were obtained from melting the above PIBA in an electric-furnace at 1450 °C for 1 h. and chilled by quenching in water (WIBA) and air (AIBA). Results indicate that incinerator bottom ash caused a reduction in compressive strength, unit weight, and flowability values when used as a replacement for sand and cement. However, IBA can be processed by melting to regain reactive pozzolanic activity, which may be used to partially replace cement.

scholarly journals The effect of ground limestone on the properties of composite gypsum binder using thermally activated clay as a pozzolanic component

2021 ◽  
Vol 274 ◽  
pp. 04006
Author(s):  
Marat Khaliullin ◽  
Alsu Gilmanshina
Keyword(s):  
Energy Consumption ◽  
Construction Industry ◽  
Mechanochemical Activation ◽  
Pozzolanic Activity ◽  
Optimal Amount ◽  
Thermally Activated ◽  
Preliminary Preparation ◽  
Binder Composition ◽  
Clay Ground ◽  
Ground Limestone

The purpose of this research is to study the effect of methods of preliminary preparation of thermally activated clay, which is a pozzolanic component in water-resistant composite gypsum binders, as well as the effect of mechanochemical activation in the joint grinding of thermally activated clay with the addition of a plasticizer on the pozzolanic activity and the change in the required number of pozzolanic component in the composition of composite gypsum binders. It was found that the required amount of thermally activated clay as pozzolanic component in the gypsum-cement-pozzolan composition when ground to specific surfaces of 200-500 m2/kg together with the addition of Melflux 2651 F plasticizer, based on the exclusion of conditions for the formation of an unacceptable amount of ettringite, decreases by 20-25% compared with the use of thermally activated clay ground without the introduction of a plasticizer. The optimal amount of Melflux 2651 F plasticizer introduced by grinding with thermally activated clay has been determined. The significance of the results for the construction industry lies in the fact that the use of the technology of obtaining composite gypsum binders of grinding thermally activated clay to a certain dispersion with the introduction of a plasticizer additive due to the effect of mechanochemical activation makes it possible to reduce the consumption of the pozzolanic component in the binder composition or energy consumption for grinding.

scholarly journals Experimental Study on the Characteristics of Activated Coal Gangue and Coal Gangue-Based Geopolymer

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2504
Author(s):  
Weiqing Zhang ◽  
Chaowei Dong ◽  
Peng Huang ◽  
Qiang Sun ◽  
Meng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Activation ◽  
Amorphous Structure ◽  
Coal Gangue ◽  
Lower Amount ◽  
Activation Temperature ◽  
Microstructure Changes ◽  
Thermally Activated ◽  
Activated Coal ◽  
Activated Coal Gangue

Coal gangue-based geopolymer (CGGP) is one of the hot spots existing in the recycling of coal gangue resources due to its good comprehensive mechanical properties. However, the coal gangue structure is stable and reactivity is poor, so the coal gangue needs to be activated before utilization. In this paper, the microstructure changes of activated coal gangue by different mechanical and thermal activation methods, as well as the mechanical properties and microstructure changes of the CGGP specimens were studied by experimental investigation. The results indicated that mechanical activation and thermal activation were two effective methods to change the reactivity of coal gangue, which consisted of destroying the stable kaolinite structure and improving the activity of coal gangue. Conversely, part of the amorphous structure in coal gangue was destroyed when the activation temperature reached 900 °C, which was not conducive to the further enhancement of coal gangue activity. For the CGGP prepared by thermally activated coal gangue and modified sodium silicate alkali solution, the uniaxial compressive strength of the CGGP specimens decreased with thermal activation temperatures of the raw coal gangue materials at 700 °C, 800 °C, and 900 °C. The main reason for this was the lower amount of the active metakaolin structure in coal gangue at 900 °C, which was not conducive to the geopolymerization process.

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