Applied Mechanics and Materials Vols. 253-255

Abstract: This paper will provide a review of the current research on the material characterisation and mechanical behaviour of polymer enhanced silica aerogels. Aerogels have been in existence for many years; however, the engineering applications of aerogels have been limited due to their poor mechanical behaviour. Recently a new type of polymer enhanced silica aerogel, a nanostructured form of silica has been developed. The new material is having a low density, very low thermal conductivity, excellent acoustic insulation and high mechanical which makes it ideal for energy efficient building material. This paper will discuss the start-of-the-art development of this material and issues to apply the material in energy efficient buildings.

Abstract: Papers removed due to plagiarism. The original was published by http://www.sciencedirect.com/science/article/pii/S0008884611000986

Abstract: High strength concrete (HSC) has large application because of good performance and high durability. Optimizing mix proportions has main effect on the compressive strength of HSC. In this paper, optimizing mix proportions are investigated by Taguchi method, factors of water to cementitious material ratio (W/C), fine aggregate to total aggregate ratio (FI/AG), silica fume as supplementary cementitious material and cementitious material content were selected at three levels. After testing L9 orthogonal array and analyzing results by Taguchi method, the best optimized mix levels were predicted by Taguchi. Then optimum mix was constructed and tested. It was concluded Taguchi forecast is true about optimized mix levels.

Abstract: The article analyses the possibility of using geopolymers as a matrix of sprayed concretes intended for realisation of constructions in the environment with an increased fire risk. Thanks to their specific properties, geopolymers show a high resistance to extreme temperatures. Thus, using geopolymers as a matrix shows a considerable potential in the light of development of sprayed concretes resistant to high temperatures.

Abstract: When assessing a condition of reinforced concrete structures the expert companies mostly place emphasis mainly on determination of material physico-chemical parameters (such as concrete strength parameters, reinforcement placing etc.). These figures are, of course, very important for example for structural analysis of a structure, but for complex assessment of a condition are these data fully insufficient. This article illustrates the role of physico-chemical analysis when assessing a condition of reinforced concrete structures using a specific example.

Abstract: Recently, hybrid coupled shear system, where steel coupling beam couple two or more RC shear walls are frequently applied for medium and high-rise building subjected to earthquake. This paper addresses the seismic performance of PSH2C wall - steel coupling beam with stud bolts in the connection region. Test variables included stud bolts in embedded steel coupling beam and types of material, such as PSH2C and concrete, in the wall. The results show that PSH2C wall – beam connections (PSH2C-ST and PSH2C-SB) exhibit better hysteretic response than normal concrete wall – beam connections (HCWS-ST and HCWS-SB).

Abstract: Bearing capacity of RC beam calculated by using typical dynamic computing methods can not define the truly distributed internal force all over the deflection from the beginning of load; the main reason is the change of the form of deflection and internal force to time are not taken into account. The dynamic responses of simply supported beam under shock wave are established. Based on beam dynamic equations, some formula set to solve the problem of random load is gained by using the free vibration mode method. The expression of the bearing reaction of beam is reverse under shock wave. In order to avoid bearing separation, special structure measure must be adopted.

Abstract: Research on performance of waste ceramics and ultra fine sand was carried on. And based on it, waste ceramics were crushed as recycled ceramic sand, and substituted for parts of ultra fine sand to make mortar. The feasibility, economic and social benefits of a combination of recycled ceramic sand and ultra fine sand was analyzed. The study provides us with a new solution for waste ceramics disposal and ultra fine sand usage.

Abstract: The influence and influence mechanism of three different kinds of fibers, xylon fiber, polyester fiber and basalt mineral fiber, on the pavement performance of Stone Matrix Asphalt (SMA) are investigated for optimizing the pavement performance of SMA in this paper, by comparative analysis of high temperature performance, water stability and low temperature performance of SMA with the three different types of fibers. The results suggest that there are large differences in the performance of SMA with the three kinds of fibers above mentioned, because of the different dispersibility and adsorption capacity of each fiber, and SMA with basalt mineral fiber has the best behavior in pavement performance.

Abstract: Air-entraining agent improved the concrete structural viscosity under high-frequency vibration was the reason for this characteristics. For the phenomenon that road concrete early cracking, evaporation rate and early cracking testing was done to compare the different between three curing agents by the influence to moisture loss and crack formation. Studies have shown that: curing agent not only played a role that moisturizer, but also shortened the time of its moisture loss. Then, the quantity length and width of concrete cracks were significantly inhibited because of increasing the amount of curing agent.