Applied Mechanics and Materials Vols. 357-360

Abstract: The concrete surfaces after abrasion wear test have been characterized by structural parameters, such as mean inter-particle distance; mean coast aggregates diameter, its area fraction, and matrix hardness. The specific method to obtain the inter-particle distances was developed. From regression analyses it has become evident that wear effects arising from coast aggregate fraction and their geometrical parameters surpass the influence of matrix hardness.

Abstract: One kind of engery-saving lightweight composite insulation wall panel is exploited. It can benefit of waste, effectively reduce the structural weight and can be easily to install. Comparing with ordinary concrete wall on thermal property, reveals that the lightweight composite insulation wall panel has better insulation property. Combine with the other properties and engineering applications, pointe out that the properties of the panel meet the National energy efficiency standards and the summer and cold winter energy efficiency design standards requirements of China.

Abstract: Thin wall was formed by multi-layer laser cladding. The results showed that the microstructure of the thin wall presented obviously and continuously grown dendrite and no white layer appeared between individual multi-layers. The orientated column dendrites were observed in the first layer, which was unhelpful to interfacial bonding. This is related to the effects of the substrate on the composition and cooling rate of the first layer. The interlayer bonding between other multi-layers was epitaxial growth with mutual occlusion and was helpful to the improvement of bonding intensity.

Abstract: The aim of this research is to study the effect of different curing regimes on shrinkage and strength properties of self-consolidating mortars (SCM) containing silica fume in different contents. Self-consolidating mortars, as new technology products, are especially preferred for use in architectural elements and the rehabilitation and repair of reinforced concrete structures. SCM can be used in precast architectural elements or cast in place repair of reinforced concrete structures. Therefore, investigation on the effects of different curing methods on key properties of SCMs can be beneficial. The shrinkage and strength properties of SCMs produced at different replacement ratios of silica fume (SF) with cement in different curing regimes were studied, at this paper. SCM mixes were prepared in constant water/powder ratio and cured in four different regimes including water curing (WC), accelerated water curing (AWC), air curing (AC) and aluminum tape sealing (AS). A polycarboxylate-based superplasticizer (SP) was added to the mixtures at different rates by mass of the cementitious materials to have appropriate flowability. Fresh mortars workability was determined using mini slump flow and mini V-funnel tests. All SCM specimens were tested and evaluated for compressive strength, flexural strength and shrinkage. It has been found that different curing regimes have considerable effects on both shrinkage and strength properties of SCM. It can be concluded that aluminum tape sealing and accelerated water curing can be used as effective and successful curing methods particularly where the SCM is used as a repair material or in architectural elements, respectively.

Abstract: Blends of asphalt and shape-stabilized phase change materials (SSPCM) were prepared by physical blending. Heat storage and thermal stability of asphalt-SSPCM blends were investigated by DSC and TG, chemical compatibility of asphalt-SSPCM blends was characterized by FT-IR, and the application feasibility of SSPCM in asphalt pavement was explored. The results show that asphalt-SSPCM blends have large phase change enthalpy, good thermal stability and chemical compatibility. Based on phase change theoretical analysis and numerical calculation, SSPCM applied in asphalt pavement can actively regulate and control pavement temperature using solar energy conversion or storage, lighten the asphalt pavement diseases related temperatures, enhance the performance of and prolong the service life of asphalt pavement, lower repair and maintenance cost, and enhance driving safety. At the same time, it can also saving energy sources and protect environment. Therefore, SSPCM have broad application foregrounds in asphalt pavement.

Abstract: Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.

Abstract: Composite thermal insulation material can be made from expanded and vitrified small balls and other inorganic insulation lightweight aggregate. According to the hydration, hardening mechanism of inorganic gel material and materials thermal insulation mechanism, we can eliminate the heat convection of gas inside the holes by using foaming technology, and micro holes can reduce radiation heat transfer between the pore walls so as to further improve the thermal insulation properties of solid materials.

Abstract: The performance of magnetorheological (MR) elastomers can be controlled by an applied field, so we can design intelligent isolators with adjustable and controllable parameters. All isolators more or less suffer from creep deformation, and the intensity will directly affect the service life of the equipment to be isolated. In this paper, NDI polyurethane-based MR elastomers were prepared and their creep properties were tested. The results show that as the filling mass fraction of carbonyl iron powder was increasing, the creep intensity in MR elastomers was first increased and then reduced; when the mass fraction was 70%, the creep intensity was less than that of the base material. Therefore, the creep property of MR elastomers can be improved by designing an appropriate content of carbonyl iron powder according to use requirement.

Abstract: A kind of refractory fiber cardboard functioning as building insulation materials was developed. To improve the cardboard abilities to bear high temperature, sepiolite and alumino-silicate fibers were chosen as the raw materials for making refractory fiber carboard. In addition, inorganic adhesives and PVA fiber were used as bonding agents to enhance the physical strength of cardboard. The effect of bonding agents amount on tensile strength of the cardboard were investigated. When choosing inorganic adhesives and PVA fibers as the adhesives, the optimum condition is that amount of aluminum sol and PVA fibers is 30%and 3%-4% by weight, respectively; The best technical conditions for making the refractory fiber cardboard were determined. When the mass ratio of alumino-silicate fibers, sepiolite fiber, PVA fibers is 90: 6: 4, the physical strength of refractory fiber cardboard can be up to 1.556N·m/g. When the bulk density of the cardboard is 305.8kg/m³, the thermal conductivity of insulation cardboard at 200°C is very low, which is only 0.065W/m·K.

Abstract: The presented research focuses on the investigation of the efflorescence process and its structure and morphology. It aims at the development rational methods to prevent the efflorescence risk, taking into account the specifics of fine grained concrete paving blocks.