scholarly journals Pozzolanic activity of metakaolins by the French standard of the modified Chapelle test: A direct methology

2015 ◽  
pp. 289-298 ◽  
Author(s):  
Eduardo Ferraz
Keyword(s):  
Pozzolanic Activity ◽  
French Standard

Mechanoactivation Of Rice Husk Ash In Laboratory Conditions

2019 ◽  
pp. 20-26
Keyword(s):  
Mechanical Activation ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Silicon Oxide ◽  
Rice Husk Ash ◽  
Pozzolanic Activity ◽  
Maximum Solubility ◽  
Laboratory Conditions ◽  
Before And After ◽  
Mineral Additive

In many rice producing countries of the world, including in Vietnam, various research aimed at using rice husk ash (RHA) as a finely dispersed active mineral additive in cements, concrete and mortars are being conducted. The effect of the duration of the mechanoactivation of the RHA, produced under laboratory conditions in Vietnam, on its pozzolanic activity were investigated in this study. The composition of ash was investigated by laser granulometry and the values of indicators characterizing the dispersion of its particles before and after mechanical activation were established. The content of soluble amorphous silicon oxide in rice husk ash samples was determined by photocolorimetric analysis. The pizzolanic activity of the RHA, fly ash and the silica fume was also compared according to the method of absorption of the solution of the active mineral additive. It is established that the duration of the mechanical activation of rice husk ash by grinding in a vibratory mill is optimal for increasing its pozzolanic activity, since it simultaneously results in the production of the most dispersed ash particles with the highest specific surface area and maximum solubility of the amorphous silica contained in it. Longer grinding does not lead to further reduction in the size of ash particles, which can be explained by their aggregation, and also reduces the solubility of amorphous silica in an aqueous alkaline medium.

scholarly journals Quantitative Comparison of Binary Mix of Agro-Industrial Pozzolanic Additions for Elaborating Ternary Cements: Kinetic Parameters

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2944
Author(s):  
Ernesto Villar-Cociña ◽  
Moisés Frías ◽  
Holmer Savastano ◽  
Loic Rodier ◽  
María Isabel Sánchez de Rojas ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Sugar Cane ◽  
Research Work ◽  
Pozzolanic Reaction ◽  
Reaction Rate Constant ◽  
Pozzolanic Activity ◽  
Binary Blend ◽  
Activation Free Energy ◽  
Pozzolanic Reactivity ◽  
Bamboo Leaf Ash

In this research work, the quantitative characterization of a binary blend comprised of two pozzolans (sugar cane straw (SCSA)–sugar cane bagasse ashes (SCBA), bamboo leaf ash (BLAsh)–SCBA and paper sludge (PS)–fly ash (FA)) taking into account the calculated values of the kinetic parameters of the reaction in the pozzolan/calcium hydroxide system is shown. The paper shows the most significant and important results obtained by the authors in the quantitative assessment (calculation of kinetic parameters) of the pozzolanic reaction of different mixtures of pozzolanic materials that are residues from agriculture or industrial processes. This allows a direct and rigorous comparison of the pozzolanic activity of the binary combinations of materials. The values of the kinetic parameters (reaction rate constant or activation free energy) constitute a very precise quantitative index of the pozzolanic activity of the binary combinations of materials, which is very useful for its employment in the elaboration of ternary cements. This paper shows that the binary blends 1SCBA60Blash40, 1SCBA50Blash50, 1SCBA70Blash30 have a very high pozzolanic reactivity followed by PSLSFA, 2SCBA50SCSA50, PSISFA and SCWI.

scholarly journals Mechanochemical treatment of Serbian kaolin clay to obtain high reactive pozzolana

2013 ◽  
Vol 78 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Aleksandra Mitrovic ◽  
Miodrag Zdujic
Keyword(s):  
Hardened Steel ◽  
Pozzolanic Activity ◽  
Mechanochemical Treatment ◽  
Kaolin Clay ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Milling Parameters ◽  
Milling Medium ◽  
The Given

Mechanochemical treatment of Serbian kaolin clay was carried out in a planetary ball mill using two different milling media, hardened steel or zirconia vials and balls. The samples obtained with various milling times were characterized by the particle size laser diffraction (PSLD), X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DTA/TGA) and Fourier-transform infrared (FTIR) analyses. Mechanochemical treatment induced amorphization of the kaolinite phase accompanied by dehydroxylation. It was found that for the given milling parameters, amorphization mainly took place in the milling period up to 15 min, and was completed after about 30 min of milling for both milling media used. The pozzolanic activities were determined by the Chapelle method. Milling in the hardened steel milling medium had no significant influence on pozzolanic activity, even though there was accumulated iron contamination. For both milling media, pozzolanic activity of 0.79 was obtained for the samples milled for 15 min and it remained almost unchanged with prolonged milling. The determined pozzolanic activity values are close to these of commercial metakaolinite or metakaolinite obtained by the calcination of the same clay, therefore, indicating possibility for obtaining high reactive pozzolana by mechanochemical treatment of Serbian kaoline clay.

A structural investigation relating to the pozzolanic activity of rice husk ashes

2008 ◽  
Vol 38 (6) ◽  
pp. 861-869 ◽  
Author(s):  
Deepa G Nair ◽  
Alex Fraaij ◽  
Adri A.K. Klaassen ◽  
Arno P.M. Kentgens
Keyword(s):  
Rice Husk ◽  
Structural Investigation ◽  
Pozzolanic Activity

Pozzolanic activity of calcinated low-grade natural sepiolite and its influence on the hydration of cement

2021 ◽  
Vol 309 ◽  
pp. 125076
Author(s):  
Chun-Ran Wu ◽  
Zhi-Qiang Hong ◽  
Bao-Jian Zhan ◽  
Shi-Cai Cui ◽  
Shi-Cong Kou
Keyword(s):  
Pozzolanic Activity ◽  
Low Grade

Study of the impact of waste glasses types on pozzolanic activity of cementitious matrix

2019 ◽  
Vol 197 ◽  
pp. 626-640 ◽  
Author(s):  
Abdelhadi Bouchikhi ◽  
Mahfoud Benzerzour ◽  
Nor-Edine Abriak ◽  
Walid Maherzi ◽  
Yannick Mamindy-Pajany
Keyword(s):  
Pozzolanic Activity ◽  
Cementitious Matrix ◽  
The Impact

An investigation on pozzolanic activity of Iranian kaolins obtained by thermal treatment

2015 ◽  
Vol 103 ◽  
pp. 34-39 ◽  
Author(s):  
Alireza Souri ◽  
Farhad Golestani-Fard ◽  
Rahim Naghizadeh ◽  
Sohrab Veiseh
Keyword(s):  
Thermal Treatment ◽  
Pozzolanic Activity

Study of the pozzolanic activity and hydration products of cement pastes with addition of natural zeolites

Clay Minerals ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 241-250 ◽  
Author(s):  
V. Lilkov ◽  
O. Petrov ◽  
V. Petkova ◽  
N. Petrova ◽  
Y. Tzvetanova
Keyword(s):  
Surface Area ◽  
Cement Paste ◽  
Chemical Reactions ◽  
Natural Zeolite ◽  
Early Stage ◽  
Pozzolanic Activity ◽  
Large Surface Area ◽  
Natural Zeolites ◽  
Hydration Products ◽  
Cement Pastes

AbstractThis paper presents results from comparative thermogravimetric, calorimetric and pozzolanic activity analyses of five natural zeolite samples from Bulgaria, Slovakia, Philippines, USA and North Korea. The zeolites actively participate in the hydration processes of cement. Their activity in the early stage of hydration is based mainly on the large surface area of the particles while, in the later stages of activation, chemical reactions occur between the products of the hydration of cement and the soluble SiO2 that is present in the bulk of the zeolites. It has been shown that in all cement pastes which contain zeolite additives, the quantity of portlandite is lower than that in pure cement paste or is even totally absent. The amounts of hydration products are greater when 30% zeolite is used than when 10% zeolite is added (excluding the sample with chabazite). The lowest pozzolanic activity is shown by chabazite, which possessed the lowest SiO2/Al2O2 ratio.

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