Applied Mechanics and Materials Vols. 71-78

Abstract: Soft ground with low bearing capacities is found to large areas in the world. In order to increase the bearing capacity of soft ground and to decreases settlement, some methods were developed for improving the mechanical properties of ground. As a stiffener of soil improvement, bamboo chips were used in this study. Bamboo is one of the fastest-growing plants on Earth and with a large distribution around the world. As a natural material, it is even better for environment and has excellently mechanical characteristic. The bamboo chips were mixed into the test specimen as a stiffener of soil improvement. Unconfined compression test were performed with test specimen, then mechanical characteristics of reinforced soil by cement and bamboo chips were investigated. From the test results, the strength and ductility characteristic of soil improvement are rather better when the bamboo chips are mixed.

Abstract: The degradation of reinforced concrete structures due to chloride penetration has a significant influence on structural durability. In this study, an experiment is conducted to investigate the effects of the aggregate type, mixing method, and admixture type on the chloride penetration resistance of concrete. Based on the experimental results, it is found that, since more pores and microcracks are included in recycled aggregates, the chloride penetration resistance of recycled aggregate concrete is larger than that of natural aggregate concrete. Slag is more efficient than fly ash in increasing the chloride penetration resistance of recycled aggregate concrete. It is also found that the mixing method has a significant influence on the chloride penetration resistance of recycled aggregate concrete. These conclusions can provide theoretical evidence for the design optimization of recycled aggregate concrete properties.

Abstract: This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The warm mix asphalt (WMA) refers to technologies that allow a significant reduction of mixing and compaction temperatures of asphalt mixes through lowering the viscosity of asphalt binders. In this paper, Shell90 # and SK70 # are two matrix asphalt with Sasobit® modifier to prepare for WMA's penetration and ductility, and calculate the equivalent crisp points, evaluate the low temperature performance at 5°C and 15°C, respectively. The results indicate that compared with the Shell90# without and with 5% Sasobit®, its penetration and ductility were reduced by 24.5%, 65.5% at 15°C. For SK70#, its penetration and ductility were reduced by 25.0%, 67.1%. WMA equivalent crisp points test with Shell90 # and SK70 #, compared with the matrix asphalt reduced by 10.03°C and 4.02°C, the addition of 3% Sasobit® to two matrix asphalt binders may also reduce ductility by 22.5% and 26.2%, respectively at 5°C.

Abstract: The article presents an study on the rheological properties of cement grouts with different water-cement ratios of 0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.9,1.0,1.1,1.25,1.0,2.0,5.0 and10.0.It was to investigate different water-cement ratios of cement grouts effecting its flow pattern properties, and thus determinate the conversion point of them among Newtonian fluid, Bingham fluid and Power-law fluid. It confirmed that,when take into accounts of all negative factors possibly affecting the experiment, including asynchronous loading steps, water temperature, apparatus deflection and so on, W/C(water-cement ratio) = 0.75 is a inflection point,which Power-law fluid converted into Bingham fluid, while at W/C =1.25 the cement grouts suffered a conversion from Newtonian fluid to Bingham fluid. This research results supplied, improved and expanded the knowledge of the flow pattern properties of cement grouts and conversion condition with different water-cement ratios, and so it has important theory meaning and realistic value and may contributes to the engineering practices.

Abstract: Northeast heat supply is an eternal demand, it would cost tens of thousand of moneys for heat supply, on the other hand, the resource of coal and fossil fuels is non-renewable source of energy, in the future it will be consumed, so it is still a serious problem to solve the winter heat supply. At the same time, the hot dry rock has three essential factors including a huge number, renewable and not polluting the environment, which will open up new ways on heat supply in cold area. Based on its advantages the paper will design a heated system more effective than the technology of shallow ground source heat pump, meanwhile analysis the key technology during exploiting the hot dry rock progress, then the thermal conductivity of rock under high temperature and high pressure and the heat transfer ability between rock and water as well as pipe material and insulation technology, all of which will realize the key technology about the dry-heat rock heating. In conclusion, if the key technology on heated system would be settled, it will bring breakthrough about using the hot dry rock on heated supply in cold areas.

Abstract: With the background of global warming and energy crisis, the low carbon economy and low carbon city gradually call people’s attention. The core of low-carbon city and economy is to reduce carbon emissions and energy consumption. A low-carbon city relies on its low-carbon city planning. This article analyzes the connotation of low-carbon city and puts forward the notion of using low-carbon ideas in planning industrial structure, road transport planning and layout of the city to construct a better city.

Abstract: High-strength flowing concrete is made of large volume of gelled materials and high rate of sand, but low content of coarse aggregate and small grain diameter, which makes it easy to have a greater contraction, resulting in reduced strength and durability of concrete[4] .So the right amount of expansion admixture is needed to ensure that there is no shrinkage or micro-expansion of the concrete. In this paper, the right mixing ratio of the concrete will be achieved, which is consistent with needs of project, by designing tests of mixing ratio of different gelled materials (cement, fly ash, silica fume and expansion admixture) and mix design of high-strength fluid and micro-expansion concrete with the CAN admixture inside and by measuring its performance.

Abstract: Boron mud haydite adsorbent which was made of boron mud, bentonite, flyash, saw dust, was applied in treatment of high turbidity wastewater. The removal rate of turbidity was used as the index, and the pH the value, the flow, the filler height, the saw dust content, the size and the processing time were studied. The results showed that the removal rate of turbidity which raw turbidity was 795~820NTU could reach 94% when the pH was 12, the flow was 1200s•L-1, the filler height was 50cm, the size was 4mm, the saw dust content was 40g, and the processing time was 60min.The study provided a new way in the preparation of adsorbent and an application of high turbidimetric wastewater treatment.

Abstract: With the development of economy and growth of population, China’s building materials has seen tremendous growth in recent years, more attention is paid to help manage the sustainability challenges of building materials. This paper tries to build a conceptual framework to integrate The Natural Step Framework, Life Cycle Assessment and Ecological Footprint and attempt to analyse how it works in the management of a sustainable transition.

Abstract: To improve the porosity of ceramsite concrete can also improve its sound-absorbing property. In this paper, the expanded perlite, polypropylene fibers and foaming agent were added to improve the porosity of the ceramsite concrete. The results show that these three kinds of raw materials can enhance the sound absorbing properties of samples. The relations between porosity and the sound absorption in different sound frequencies through microstructure analysis were established. The study also found that the polypropylene fiber can improve the strength of materials, on the contrast, expanded perlite and foaming agent can significantly reduce the strength. The mechanisms were analyzed by SEM photos.