Applied Mechanics and Materials Vols. 174-177

Abstract: Traditional road green growing material does not take into account the particularity of green traffic areas. Characteristic of the road greening and ordinary green standard is not the same. In road greening projects, vegetation planting layer is required to meet the basic conditions for plant growth, in addition vegetation planted layer need structural requirements. Fired brick and tile waste material have microporous structure. The pore structure is capable of storing water and nutrients, fired brick and tile waste materials have the stronger crushing strength and frost resistance. Fired brick and tile waste can satisfy the dual needs of the structure and plant growth. These characteristics determine fired brick and tile waste to have enormous potential in the road greening projects.

Abstract: Using ordinary material, calculating through the external addition method and then adjusting through experimental tests, the mixing proportion of cement mortar is determined. The testing results show that: when the water cement ratio is 0.50, the fly ash content is too large and the strength of cement mortar will sharply decrease with the increase of its content. Therefore, the fly ash content in engineering cannot exceed 30% of the gelled material.

Abstract: The semi-rigid base asphalt pavement has become the main form of high grade Highway pavement structure in China. But with changes in temperature, humidity and amount of traffic, serious cracking problems also exist in this pavement, affecting pavement performance. Analyses crack type of asphalt pavement and its causes, for serious reflection crack problem of semi-rigid base asphalt pavement, by on different structure type and different cement dose cement stabilized gravel mixture for indoor dry shrink and temperature shrink test research analyse variation law of its dry shrink strain, and dry shrink coefficient, and temperature shrink strain, and temperature shrink coefficient, ect. and provides basis to improve semi-rigid base asphalt pavement anti-crack performance.

Abstract: CdWO₄ nanoflakes and nanorods have been successfully prepared through a mild template-free sonochemical method without any surfactants. The as-prepared samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the ultrasound irradiation played an important role in the formation of CdWO₄ crystals. The results showed that CdWO₄ nanoflakes were first formed at the early stage, and CdWO₄ nanoflakes were transformed into nanorods as the ultrasonic time was prolonged from 0.5h to 1.5h.

Abstract: A lot of cracks appeared on the surface of stainless steel strands, which have been installed for only a few months in a building construction. This paper analyzes the crack morphology, observes the fracture both macroscopically and microscopically, and analyzes its energy spectrum. Based on this, the hardness and chemical component of the steel strands are detected, and combined with metallographic analysis it is concluded that the property of the cracks on these steel strands are stress corrosion crack and the reason is that other strands whose corrosion resistance is much less than stainless steel 316 are mixed into these strands.

Abstract: Fire does great harm to concrete structure's safety and applicability. And it should not be neglected that fire also does great harm to concrete's durability. Due to fire's high temperature and harmful product, concrete in the fire scene undergoes severe chloride erosion. The mechanism that affect fire's erosion on concrete is different from usual conditions, and it deserves further study on both erosion mechanism, influence factors, chloride erosion prevention measures, and the Calcium Silicate Hydrate decomposition under high temperature, which can be of significant meaning in concrete structure damage evaluation and effective structure maintenance and reinforcement after fire.

Abstract: SiC/Cu composite materials were fabricated by powder metallurgy, and microstructure of composite was analyzed by means of metallographic microscope. The high speed steel tool and cemented carbide tool are used as cutters, and machining performance of SiC/Cu Composites were studied by cutting lathe and wire-electro discharge machine. The relationship between wire-electro discharge machining cutting speed and pulse interval were studied by wire-electro discharge machine. The results show that the composite cutting surface roughness increases with increasing of the content of SiC particles when the size of SiC is 40μm, while composite cutting surface roughness decreases with increasing of the content of SiC particles when the size of SiC is 20μm, the cemented carbide tolls have longer life than high-speed steel tools. The surface roughness of composite increases with the increasing of source voltage, but it decreases with increasing of pulse interval in the wire-electro discharge machining cutting conditions.

Abstract: This article uses the thermal analysis to study the kinetics characteristics of Polyurethane foam. The partially oxidized and non oxidized materials were used to study the variation of reaction of the smoldering, and the mechanism of function and activation energy of two substances was obtained. The result show that the oxygenolysis of the non oxidized Polyurethane foam belongs to the second-level chemical reaction, while the oxygenolysis of partially oxidized belongs to the first-level chemical reaction; the oxidization reaction of Polyurethane foam is a process which have lots of reaction steps to mutual promote as well as connection with each steps ; Through the smoldering experiment verify that the response characteristics of the two substances under the same heat flux to a certain extent, and the results agree well with the calculated activation energy.

Abstract: With the process parameters and processing conditions in the mill, a systematic experimental research were conducted to Q345 steel containing niobium austenite grain growth law, and analysis the dissolution and precipitation behavior of Nb carbonitride. The results shows that Nb-microalloyed steel heated to 1180 ~ 1230 °C can significantly improve strength and toughness of steel and performance.

Abstract: The experiment undertaken at the Ramakrishna Mission’s educational campus at Coimbatore, India, targeted developing pre-cast elements for masonry walls that will: reduce construction time; give stony outer appearance to walls; and use environmentally friendly methods, raw materials, and currently available technology. This paper describes methods and equipment for manufacture of pre-cast elements from coursed rubble stones and concrete, called here the Pre-Cast Coursed Rubble (PCCR) blocks, developed during the experiment. It will be clear that use of these blocks in walls speeds construction, requires less skilled labour, improves appearance, and reduces material and labour costs.