Applied Mechanics and Materials Vols. 357-360

Abstract: Explicit finite element code was applied to simulate the steel fiber reinforced concrete (SFRC) and reactive powder concrete (RPC) target penetrated by kinetic energy projectile. Crater formation, spall of concrete target in penetration process was simulated very well. The numerical results of penetration depths are in good agreement with recent experimental results obtained from ballistic gun with 57mm caliber. The factors effecting on anti-penetration property of SFRC and RPC are analyzed. The results show that: the compressive strength and toughness of the target body have greater impact on anti-penetration performance in the range of projectile velocity 300m/s-600m/s. Anti-penetration capability of RPC concrete is stronger than that of ordinary steel fiber at the higher speeds.

Abstract: To study the biaxial strength and failure characteristics of reinforced concrete in the state of biaxial tension-compression stresses and provide some suggestions for the practical engineering design, 3 one-third scale reinforced concrete (RC) plate specimens are tested. The results indicate that, in biaxial tension-compression stresses, reinforced concrete cracks in the direction normal to the principal tensile stress direction and presents the characteristics of shear failure modes. The test device could simulate the required stress condition. The compression strength of reinforced concrete is obviously lower than the uniaxial strength f_c. The reduction factor k is about 0.55~0.75 which varies with different tension-compression force ratio. Concrete material takes part in the tension process of reinforced concrete and shares part of the tension, while the share ratio decreases as concrete cracks gradually.

Abstract: In order to use the alkaline ingredient in red mud, this paper studied the strength variation law of alkali-activated red mud and lime cement material combined with slag. When the content ranged from 0 wt% to 20 wt%, the experiment showed that the flexural strength increased when the content increased, and the compress strength increased when the content increased with the content ranging from 0 wt% to 15 wt%. When the content reached 25 wt%, the strength of alkali-activated red mud cement material was equal with alkali activated slag cement. The SEM test of alkali-activated red mud cement material showed that red mud and lime both participated in hydration reaction fully.

Abstract: Wood is a remarkably versatile building material. Density is an important indicator of woods properties, which directly impact on the physical, mechanical and processing and using performance. Therefore, it is very significant to research wood density. To predict China fir density, this paper use near-infrared spectroscopy and wavelet transform threshold, wavelet transform modulus maxima and moving variance method to de-noise near-infrared spectroscopy of the first derivative of the wood. We also build wood density partial least squares analysis model and compare them with the model built by the traditional near infrared spectral preprocessing methods. The results show that wavelet transform and moving variance can effectively remove noise in the derivative spectra and improve the accuracy of the spectral analysis model, which means the introduction of Near Infrared Spectroscopy has a great prospect of application in the analysis of building materials.

Abstract: Decoration materials, as an essential part of architectural design, play a prominent role in the success of the entire architectural design. It not only meets the environmental requirements but embodies aesthetic value to some extent. Starting from the selection and application of decorative materials, this paper explored the method of decoration materials application in buildings from the perspective of how to achieve a perfect combination of decoration materials and detail design of a building and how decoration materials echoes with the built environment. In the understanding of material properties,as a full integration of design and technology and art was realized, construction quality was improved. Keywords: building; decoration materials; detail design; environment; new materials; application

Abstract: Sulpho-aluminate cement as the base material, rapid hardening cement-based grouting material can be formulated. In this paper, a study on grouting material fluidity and mechanical properties in different cement-sand ratios and nanoSiO₂s impact on the performance of the grouting material is made. Based on the test, it can be learnt that Sulpho-aluminate cement as the base material, grouting material flow and mechanical properties can better meet the engineering requirements with nanoSiO₂ of 1.0% and in a cement-sand ratio of 1:1.3.

Abstract: By using the 2000kN static and dynamic triaxial test instrument the mechanical properties of the low elastic modulus concrete is studied. The results of the experiment show that the failure modes of the unconfined compression test is crushing-type and the failure modes of the triaxial compression test is shearing-type. Utilizing the Mohr - Coulomb strength theory to design the low elastic modulus concrete cut-off wall is more in line with the actual engineering, but utilizing the first strength theory to design the dam cut-off wall is safer.

Abstract: The study on metakaolins inhibit effect to alkali-silica reaction (ASR) of slate aggregate by the way of accelerated mortar-bar test (AMBT),the results show that when the gel contains 15% metakaolin,the 14d expansion ratio is less than 0.03%,the inhibit reach the wear goal. But when we add the content of metakaolin, the expansion ratios are similar at every age.

Abstract: The cause and prevention of concrete carbonation are core issues in the engineering community. With the improvement of the global CO2 concentration, more and more reinforced concrete buildings are faced with the problems of carbonation acceleration and following threats of steel corrosion which will heavily undermine the safety and durability of R.C. structures. The article from three major aspects, Concrete carbonation mechanism, causes of carbonation and carbonation influences, reviews and summarizes the current researches on carbonation and proposes valuable suggestions.

Abstract: The interval estimation for the presumption of structure concrete strength should be gained because of strong randomness of test data. For further exaltation of accuracy and credibility test concrete strength, analytic solution of inverse regression equation for evaluating concrete strength of building materials is presented herein based on the inverse regression model. The accurate solution for the presumption of concrete strength can be obtained through the analytic solution, detection precision and reliability for the presumption of structure concrete strength can be improved with respect to the traditional point estimation method.