Advanced Materials Research Vols. 374-377

Abstract: Phase change materials were prepared by the paraffin wax as phase change materials and expanded perlite as adsorption carrier in this paper. Phase change mortar was prepared by part of the sand been replaced. The heat ability which adjusts and stores heat in the heating and cooling process with different phase change materials was researched and its mechanical properties were tested and evaluated.

Abstract: Ceramiste, a lightweight aggregate(LWA), has large numbers advantages: high strength, thermal insulation, anti-seismic and so on. The earliest ceramiste development happened in America, and then widely used in the developed countries, all that most used for buildings and bridges. However the ceramsite research was soon after the foundation of the PRC, and quickly developed around the end of the 1970s. Now ceramsite with high strength and high performance has produced all over word. Personally investigating, with the situation of the detailed technological process of clay-ceramisite and pictures, and there are some most important notices among the production. With great performance, ceramiste is widely used in some catagories, such as insulation concrete, great fillers for filtration ponds and planting.

Abstract: The scattering of subsurface cylindrical cavity near multiple semi-cylindrical alluvial valleys under incident SH waves is studied in this paper by using methods of auxiliary function, complex function multi-polar coordinates. The model is divided into two parts, Domain I is multiple semi-cylindrical alluvial valleys, and Domain Ⅱ is an elastic half space with several subsurface circular cavities near multiple semi-cylindrical alluvial valleys. A series of infinite algebraic equations is then obtained based on the displacement and stress continuity condition on “common boundary” of two parts after constructing the associated displacement and stresses expressions of each part. Numerical examples illustrate that material parameters of semi-cylindrical alluvial valleys have great impact on DSCF around subsurface cavity and DSCF dose not always decrease as wave number increases especially under incident waves with high frequency when the alluvial valleys are “softer”.

Abstract: CTSRC(cold-formed thin-walled steel reinforced concrete) structure system is one new type of industrial structure system，which uses the cold-formed thin-walled steel to replace the vertical steel bars in common reinforced concrete shear walls. This paper conducts some study on the shear behavior of walls of high rise civil building. Experiment study on both one low CTSRC and one low RC wall of equivalent reinforcement subjected to low-cycle reversed horizontal load are tested, which includes description of experinment pheonomenon, analysis of loading and failure model, load-displacement hysteresis loop curves, load-displacement skeleton curves and analysis of strain. The experiment results indicate that under the same condition there is no difference between the shear property of CTSRC and RC wall basically on failure mode and shear behavior. At last, this paper provides some suggestions about further research contents of CTSRC structure system.

Abstract: Through the simulation model test, coupling effect between single key strata and t overburden thick sandy soil layer is studied, failure character of thick sandy soil layer is obtained. Meanwhile, load transmitting law on the key strata(key block) is found. This discovery will make progress on dynamic roof structure theory.

Abstract: Cementing materials are one of the most indispensable materials for national economy and people's lives. In order to adapt new materials development demand and realize sustainable development, the present researches situation of new cementing materials have been summarized and analyzed from three aspects below: the usage of industrial wastes, organic materials, natural materials to develop new cementing material as well as developing other new cementing materials in the paper, and it also provided a reference for the new cementing material development.

Abstract: A concrete paving blocks was produced using pretreated concrete wastes as main raw material by pressure forming and steam-curing at 70°C. The test results showed that with the increase of water addition, the paving blocks increase its strength. And as the additions of water amount reach to a critical value, the compressive strength has an adverse change and decreased. As the rise of ratio of cement and wastes, the compressive strength also increases. The difference in various ratios of cement and wastes is that the difference of water needed as the compressive strength achieved its highest value. The thermal treatment temperatures has greatly influence on the compressive strength. The increments of thermal-treated temperatures induce the active material to form and cause the particle grading more reasonable in the concrete wastes, which is benefit to the shaping of specimen and increasing of strength. The maximum compressive strength of 53.2 MPa is obtained in the mixture thermal-treated at 800°C by adjusting the water additions.

Abstract: Commercial plaster (CaSO4•1/2H2O) is a material used in building construction all over the world. This construction material is used renderings in internal and dry environment because it is soluble in water. According to different studies, the plaster manually applied as renderings produces high volume of material loss (values varying from 18% to 35%). In this way, the aim of this work was to study the physical and mechanical properties from pastes made with commercial plaster and pastes obtained from hydrated plaster that was lost from their applications (recycled plaster). The recycled plaster was grounded and burnt at different temperatures in order to loose its non-evaporated water and to make possible its reuse as binder. After burning, their physical and mechanical properties were studied. The results showed that recycled plaster had a good performance as binder. Their physical and mechanical properties related to commercial plaster were very similar. In this way, the results show that it is possible to reuse the recycled plaster as binder again, which permit to contribute to a sustainable construction.

Abstract: This paper describes replacing natural gypsum with FGD gypsum as cement retarder, the influence on the working performance, compressive strength and admixture adaptability of concretes, which were prepared with fly ash cement, slag cement and ordinary Portland cement. The results indict the FGD gypsum instead of natural gypsum used as cement retarder has little difference on the working performance of concrete and additionally the FGD gypsum has no negative influence on the compressive strength and admixture adaptability of concretes.

Abstract: In many cases, service life of reinforced concrete structures is severely limited by chloride penetration until the steel reinforcement. Today, concrete with high resistance with respect to chloride penetration can be produced by internal hydrophobic treatment. The aim of this study was to fill this gap in regards to reinforced concrete structures inserted in a marine environment. Results indicated the efficacy of the hydrophobic agents in cases where capillary suction is the mechanism of water penetration. However, when the transport mechanism is permeability this product is not advisable. Moreover, it was demonstrated that the chloride diffusion coefficient is reduced by the hydrophobic agents, and the corrosion rate of reinforcement could be well protected in the treated concrete with hydrophobic agents of silane. The durability of reinforced structures can be considerably increased and can be accurately designed by the application of an appropriate and optimized protective layer.