Amorphous Material Content Research Articles

Significance of amorphous material relative to sensitivity in some Champlain clays: Reply

The sensitive-clay profile samples obtained from the St. Alban and Gatineau areas have been analysed with respect to their mineralogy, amorphous material content, pore-fluid chemistry, electrokinetic potential, and surface area. These compositional and surface properties are examined in relation to the sensitivity of Champlain clays. The importance of amorphous material in these clays is seen to be demonstrated in terms of its influence on sensitivity, viz., a high amorphous content correlates with a low sensitivity. The relevant mechanisms identified with the role of such materials are postulated to lie in electrostatic attraction, presence of micropores, and development of cementitious bonds.

Significance of amorphous material relative to sensitivity in some Champlain clays

The sensitive-clay profile samples obtained from the St. Alban and Gatineau areas have been analysed with respect to their mineralogy, amorphous material content, pore-fluid chemistry, electrokinetic potential, and surface area. These compositional and surface properties are examined in relation to the sensitivity of Champlain clays. The importance of amorphous material in these clays is seen to be demonstrated in terms of its influence on sensitivity, viz., a high amorphous content correlates with a low sensitivity. The relevant mechanisms identified with the role of such materials are postulated to lie in electrostatic attraction, presence of micropores, and development of cementitious bonds.

Cation-Exchange Behavior of Clays and Synthetic Aluminosilica Gels

AbstractCation-exchange capacities determined by methylene blue adsorption (CEC MB) and by the amount of K displaced from a K-saturated clay by NH4 (CEC K//NH4) correlate closely in five soil clays from Pennsylvania, but differ greatly in two soil clays with a large content of amorphous material. CEC MB was found to provide a more precise distinction between montmorillonite and vermiculite than CEC K//NH4. Synthetic aluminosilicate gels showed CEC K//NH4 > CEC Ca/Mg > CEC MB, but no relation to the behavior of the two soil clays with a large content of amorphous material was found.

Changes in the plasticity of a sample of Champlain clay after selective chemical dissolution to remove amorphous material

Although the effect of amorphous compounds on the undisturbed strength of Champlain clay has received much attention, the role of this amorphous material in the behaviour of the sediment following remoulding has been virtually ignored. Selective dissolution procedures on remoulded specimens revealed that removal of up to 4% amorphous material, primarily iron and silicon compounds, was associated with small decreases in specific surface area and cation exchange capacity, and large decreases in liquid limit and plasticity in ex. Analysis of X-ray diffraction traces indicates some alteration of the crystalline components during NaOH–CBD dissolution, but little alteration occurred with the KOH–NH4Ox method, the procedure which achieved maximum extraction of Fe a d Si in this study. It is tentatively concluded that the presence of amorphous material may be responsible for much of the plasticity displayed by Champlain clay rock flour. As a corollary, natural variability in the content of amorphous material in Champlain clay may be correlated with regional and stratigraphic patterns of sensitivity.

Climosequence of Ash‐Derived Soils in the Central Cordillera of Colombia

AbstractFour soils derived from volcanic ash were studied in a transect on the east slope of the Central Cordillera of Colombia. Average annual temperatures range from 8C at 3,670 m altitude to 24C at 980 m. Only the soils located in the lower part of the transect have B horizons. From highest to lowest elevation the soils are classified a Cryandept, a Humitropept, and two Dystrandepts. The sand and silt fractions of the soils consist of a similar suite of minerals, several of which are high in sodium. Volcanic glass and plagioclase are most abundant; cristobalite, quartz, vermiculite, pyroxenes, hornblende, amphibole, and magnetite are present in smaller amounts. Amorphous material predominates in the clay fraction of the soils, but crystalline minerals such as smectite, vermiculite, chloritic intergrade mineral, imogolite, halloysite, kaolinite, and some primary minerals are also present.The genesis of the soils is controlled chiefly by climate and by the nature of the parent material. As the environmental temperature increases, the degree of B horizon development increases, clay content increases, organic matter content decreases, degree of weathering of primary minerals increases, and the content of amorphous material, kaolinite, and halloysite increases.

Étude de la cristallisation des polymères. IV. Influence de la distribution de la masse moléculaire sur l'épaisseur des lamelles d'un polyoxyéthylène.

AbstractA 28,000‐molecular weight poly(ethylene oxide) sample has been fractionated in stages by precipitation in order progressively to remove short‐chain material. Low‐angle X‐ray diffraction patterns have been recorded for each Stage to determine the thickness of crystalline lamellae. This thickness increases regularly as the proportion of short‐chain material decreases, showing the great influence of polydispersity and content of amorphous material on the polymer structure.

Clay minerals of volcanic ash in japan

Soils formed from volcanic ash distributed by several volcanos in the northeastern part of Japan have been studied by means of X-ray diffraction, infrared spectroscopy, differential thermal analysis and chemical analysis. The content of amorphous materials of the clay less than one micron is about seventy five per cent in the early stage os weathering, and is about forty per cent in the advanced. The essential minerals of the soils in every stage of weathering are 14A clay minerals. The kaolin minerals are found in small amounts. The weathering sequence of the volcanic ash soils in this district based on the mineralogy appears to be as follows: Volcanic ash soil - allophane - montmorillonite - vermiculite-Al chlorite intergrade The small amounts of halloysite, Al-chlorite and illite are found in every stage.