Precise crystal structure determination of the Halloysite is extremely challenging because Halloysite naturally occurs as small cylinders and the ideal single crystal sample is unavailable. The up-to-date ICSD does not have the cystal structure data of Halloysite. With the development of computer science and technologies, the X-ray powder diffraction technologies have been commonly used in the crystal structure determination. This paper attempts to obtain the refined crystal structure of Halloysite by using the X-ray powder diffraction, on the assumption that the Halloysite and Kaolinite have a similar cystal structure, that is, the 1:1 phyllosilicates structure. The structure refinement program Rietica 2010 is used in this paper.

The oil-shale-dreg is the wastes after refining the oil shale to obtain the shale oil. But in the oil-shale-dreg, there are the massive mineral component, like the quartz, the feldspar, the clay ingredient and so on. After calcined, its structure becomes loose, owning the very low density and much ignition loss. In our study, we use different rate of oil-shale-dreg, bauxite and flux for granulation by using disk granulator. After high temperature we get low density Petroleum Proppant. The proppants have the high strength and the high flow conductivity. That is satisfied the national standards by adding 30% wt solid waste oil-shale-dregs residue to the bauxite.

Damage-induced local response is probably easy to be captured by the higher modes of the structures, especially for the small defects. The aim of this paper is to overcome the inherent deficiency of fractal dimension to identify crack when implemented to higher mode shapes. The proposed approach reconstructs the higher mode shape through rotation transformation, and then the fractal dimension analysis is implemented on this new mode shape to yield a fractal dimension trajectory. The location of the crack can be determined by the sudden peaks at the fractal dimension trajectory. The applicability and effectiveness of the proposed method is validated by using numerical simulations on damage identification of a cracked cantilever beam.

This paper contributes to numerically study the mechanical behavior of cement paste under compressive pressure. First, the main results from an experimental study on the mechanical behavior of cement paste are studied. Then an elastoplastique model with two flow mechanisms is proposed to describe the mechanical behavior of cement paste subjected to confining pressure. A particular emphasis is put on the pore collapse mechanism which is developed at higher confining pressure. Finally, numerical simulations and experimental data are compared in order to verify the capacity of the proposed model to reduce numerically the basic characteristics of cement paste under different levels of confining pressure.

The mechanical behavior of a compacted unsaturated clay soil was experimentally investigated. Volume changes were investigated using a conventional odometer cell under a series of constant confining pressures, following a wetting path. The special loading paths were utilized to reflect field conditions associated with the compacted earth structure in earth filled embankment. The soils used in the experiments were taken from an earth dam. The compacted specimens were consolidated under k0-oedometer conditions. The volume change and the water content variation were measured during the tests. The influence of the confining pressure and the initial water saturation were taking into considerations. The experimental results show that the volumetric deformation properties of the remolded unsaturated soil could be expansive and/or contractive, depending on the confining pressure and the initial water saturation. It is also observed that for the mediate confining stress, there volumetric deformation of specimen applied to wetting loads has a transition from dilation to contraction.