Influence of swelling on reaction efficiency in intercalated clay minerals

1988 ◽  
Vol 92 (21) ◽  
pp. 6078-6081 ◽  
Author(s):  
Philip A. Politowicz ◽  
John J. Kozak
Author(s):  
Jun Wu ◽  
Zuhua Deng ◽  
Yongfeng Deng ◽  
Annan Zhou ◽  
Yunsheng Zhang

The strength of cement stabilized clay is less than that of concrete and mortar and shows a distinct variability owing to the existence of various clay minerals. To better understand the cement-clay reactions and the strength generation, two artificial clays with the unique clay mineral and major strength-producing constituents of cement clinker were investigated via mechanical, compositional, and microstructural analyses. Results show that C3A-stabilized clay gains strength rapidly in the first three days, but this favourable tendency vanishes over time. After 90 days of curing, the strength of C3S-stabilized clay is about four times that of the corresponding C3A-stabilized clay, indicating the remarkable long-term stabilization efficiency of C3S. Furthermore, clay minerals primarily draw into strength evolution in the reaction process. Despite that bentonite is more reactive than kaolin as long as the highly alkaline conditions persist, it has a higher probability to flocculate into large aggregates during the mixing process, which may impair the reaction efficiency and even brings adverse stabilization effects, suggesting the importance of uniformity control.


1989 ◽  
Vol 93 (2) ◽  
pp. 923-926 ◽  
Author(s):  
Philip A. Politowicz ◽  
Linda Bik San Leung ◽  
John J. Kozak

Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..


Author(s):  
J. Thieme ◽  
J. Niemeyer ◽  
P. Guttman

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.


2018 ◽  
Vol 52 (4) ◽  
pp. 317-333 ◽  
Author(s):  
Jaeguk Jo ◽  
Toshiro Yamanaka ◽  
Tomoki Kashimura ◽  
Yusuke Okunishi ◽  
Yoshihiro Kuwahara ◽  
...  

2010 ◽  
Vol 30 (4) ◽  
pp. 57-66 ◽  
Author(s):  
Qian GE ◽  
Fengyou CHU ◽  
Jingpu LIU ◽  
Yuansheng DU ◽  
Zuo XUE ◽  
...  

2011 ◽  
Vol 31 (3) ◽  
pp. 11-16 ◽  
Author(s):  
Xianhong LAN ◽  
Xianjun ZHANG ◽  
Xinbo LIU ◽  
Rihui LI ◽  
Zhixun ZHANG

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