Applied Mechanics and Materials Vols. 548-549

Abstract: This paper aims to find the gaps in knowledge in the study of green design performance for refurbishment projectsduring design process in the Malaysian construction industry. This includes critical review and analysis of findings by other well known researchers on the need to establish the theoretical frameworks of green design performance in refurbishment project. Literature review found that project characteristics and design team attributes are the variables. The literature review forms the basis for findings the gap in knowledge that is useful for authors to further research in this area of study.The paper concludes with the discussions on how each variables correlate with another variables which eventually formed the theoretical framework and hyphotesis.

Abstract: It has been proved that the construction schedule management was an uncertain problem. Traditional CPM method was a good way to define the total duration and critical paths but can not solve uncertainty. The paper use CPM to define the duration and critical path firstly, then defined the parameters with Delphi and make Monte Carlo simulation. Through simulation results, it is found that the probability to finish the work on time was only 35.3%. The following step is to make sensitivity analysis, through the calculation, the work which has large influence was found and treat as key control points. It is proved that Monte Carlo simulation is useful to solve the problem of construction schedule management.

Abstract: With the wide application of FRP reinforced concrete structure, the durability of FRP reinforced concrete structure causing more and more attention . This paper introduce domestic and foreign research situation of durability of FRP reinforced concrete structure in three aspects including FRP material, epoxy resin and FRP reinforced concrete structures .

Abstract: In this work, methods of introducing water-resistance to foamed gypsum were firstly adopted to investigate the influences of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion on the mechanical strength、water absorption and softening coefficient. Scanning electron microscopy (SEM) was conducted to investigate microstructure of gypsum and phase composition of substances on plaster surface as well as the mechanisms. The result showed that sulphoaluminate cement reduced the water absorption of foamed gypsum, which decreases to 38.9% when dosage was 10%; Redispersible latex powder reduced the water absorption of foamed gypsum, which decreases to 35.6% when dosage was 5%; Stearic acid emulsion reduced the water absorption of foamed gypsum, which decreased to 30.1% when dosage was 3%; The combing use of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion maked the water absorption decrease to 15.2% and the crystals became short and dense and a layer of organic hydrophobic membrane covered the surface of crystals and which makes gypsum less soluble and more suitable for use in humidity environment.

Abstract: The ordinary Portland cement was used to prepare foamed cement by the chemical foaming method. In this paper, the effect of superplasticizer on the water absorption and softening coefficient of foamed cement has been studied. The results show that the superplasticizer could improve foam structure, reduce the water absorption, and enhance the compressive strength and softening coefficient. The water resistance could be improved. When the dosage of superplasticizer was 0.3% (the quality of cement), compared with blank sample, the water absorption reduced 27.9%. When the softening coefficient was 0.68, softening coefficient increased 19.2%. The action mechanism of superplasticizer has been explored.

Abstract: The effect of admixtures on the mechanical properties of recycled fine aggregate cement mortar was studied. The result indicated that compared with blank samples the 28d flexural strength, the compressive strength and osmotic pressure of cement mortar were increased by 15.6%, 35.5%, 41.1% respectively when adding silicone waterproofing agent 0.2wt%, naphdalin series water reducer 1.0wt%, polycarboxylate superplasticizer 0.8wt%. The micro-morphology and hydration products of mortar specimens was observed by SEM, XRD respectively.

Abstract: Wenchuan earthquake caused a large number of masonry structure cracks, crack grouting become a very important link in the process of engineering structure reinforcement repair. This paper makes the statistical analysis on the structural seismic damage crack characteristics first, then determine the mechanism and characteristics of the cracks. Analysis of the reinforcement and repair mortar bond strength and practical range, put forward some requirements for crack repair and grouting material. Combined with grouting equipment, formed an earthquake damage of structure crack grouting construction technology in practical engineering , set up a complete system of grouting technology. Have a positive effect for the long-term development of repair reinforcement technology in China.

Abstract: Combining with the Pearl river underwater tunnel engineering project example from Huangsha to Fangcun in Guangzhou, this paper introduces the 3-dimensional finite element analysis ANASYS of immersed tube tunnel. According the data extracted from the actual project, immersed tube tunnel surrounding medium were studied and mechanical analysis of the interaction and its basic theory calculations. Then, calculate the results, through the establishment of model constraints division, loads and boundary conditions imposed on the grid and the immersed tube tunnel numerical simulation obtained the reasonably accurate analysis results. According to the figure of stress and strain, people can see the display of it easily .It is convenient for the design of the tube tunnels.

Abstract: In order to find the reason of concrete cracking in some construction. The mechanical property and micro-analysis of cores were tested, which drilled from cracked concrete floor. The test results indicated that alkali–aggregate reaction occurred, leading to the cracks in concrete floor. X-ray diffraction and scanning electron microscope facilitate the occurrence analysis and evaluation of cracked concrete.

Abstract: There are several factors impacting on the indoor airflows, such as building openings, ambient wind speed, occupants’ behavior and so forth. This paper concentrates on the impact of windows and interior doors on airflows in a rural multi-storey residential building. The indoor airflow simulation was carried out by using the CFD software. 3 states of interior doors were set, and 60 regions were arrayed in bedroom to observe the variation of airflows. According to data of regions, the uniformity of airflow and the thermal comfort were analyzed. Simulation results identified that closing interior doors will increase the mean age of indoor air about 7 times as it under the condition of opening doors, which is from 90s to 666s. It also shows that transom windows is beneficial to improve natural ventilation efficiency, as it can raise the average wind velocity by 40% when interior doors are closed.