فهرست مطالب

  • Volume:3 Issue: 1, 2013
  • تاریخ انتشار: 1392/01/20
  • تعداد عناوین: 7
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  • Effect of Reclaimed rubber Modification on the Rheological Properties and Rutting Resistance of Asphalt Binders
    Javad Poursharifi, Poria Hajikarimi Pages 1-6
    In this paper, the effect of reclaimed rubber modification on the rheological characteristics of asphalt binders is studied. Reclaimed rubber with the extent of 12, 16 and 20 is added to the neat asphalt binder and then shear complex modulus is obtained for neat and modified asphalt binder via Dynamic Shear Rheometer (DSR) test. Using Christensen-Anderson- Marasteanu (CAM) model, master curves of shear complex modulus and phase angle are determined and compared for both neat and modified asphalt binders. Implementing master curves and the CAM model, a standard method for determining the high service temperature of asphalt binders is used and the effect of reclaimed rubber modification on rutting resistance is studied. Results have shown that adding reclaim rubber to the neat asphalt binder improves its rheological properties and rutting resistance.
    Keywords: Reclaimed rubber, Rheological properties, Rutting, Master curve, CAM model
  • The Behavior of Type of RC Column-to-Steel Beam Connections and Scrutiny Of Behavior Coefficients
    Hassan Aghabarati, Mehran Seyed Razzaghi, Kavian Parhizkar Page 7
    (RCS) frames which are systems that dwell of concrete columns and steel beams , by optimizing the act of compressive strength of concrete and bending strength of steel due to not only a decrease in building weight in comparison to concrete structures but also having a better action in long spans frames .
    In this paper for analysis RCS behavior, a category of nonlinear Push Over analyses were achieved on typical low to mid-rise RCS buildings. 1,2,3,4 and 5 span frames with span length of 6 meters in 1 to 5 stories were elected for this project.
    The systems were controlled by using FEMA-273 and ATC-40 codes.
    Keywords: Hybrid RCS frame system, Composite structures, nonlinear Push Over analyses
  • Offgas Treatment Approaches By Focusing On Biofiltration Methods in Asphalt Factories
    Saeed Nemati Pages 7-10
    In the considered foundry emits offgas containing VOCs (especially ethanol). In order to reduce the VOC content, a compost based biofilter has been installed. In this approach, the polluted air stream enters a pre-conditioning chamber where temperature and humidity is adjusted for asphalt factories. Biofilteration has already been well established as an air pollutant control alternative. There are some physical, chemical and biological parameters which influence biofilter performance such: filter media , oxygen availability , moisture content , pH and etc. . In the considered factory emits offgas containing VOCs (especially ethanol) . It shows that may be there are still some VOCs in offgas which are not degraded by biofiltration. Biofiltration is not a suitable choice for treating the offgas of the certain foundry. Optimum off-gas temperature is between 25 and 37 DC but in this case, the bed temperature is less/more than the optimum range. In considered situation, it may be necessary to substitute biofiltration by another technology which can remove VOCs and odoriferous compounds completely. Different factors may affect the decision on application of these technologies, and also the effectiveness and cost of these technologies: VOC concentration, VOC species, and presence of halogenated VOCs, presence of catalyst poisons, particulate loading, moisture content, gas flow rate, and ambient temperature.
    Keywords: VOC, Aaphalt, Biofilter, Treatment
  • The Effects of Shallow Tunnels on Nearby Structures
    Mohammad Azadi, A. Zahedi Pages 11-15
    Nowadays, underground structures play vital role in developing different countries. Such structures are constructed in many civil activities such as development of road and railways, subways, water, gas and sewage lines, underground subways, nuclear wastes land filling, fuel storage and military installations. With an appropriate drilling method being selected, instabilities created in tunnels may be controlled, the volume of maintenance systems required in structures may be decreased, and extra costs arising from it may be decreased as well. Excavation of surface tunnels may bring about changes on the surface and in the adjacent structures. Settlement on the surface and instabilities in adjacent structures as a result of stress induction are among the most important changes of this kind. Plaxis software has been used in the research to evaluate the technical parameters of tunnel such as tunnel diameter, tunnel depth from the earth surface, drilling method and distance from adjacent structures. Meanwhile it investigates the effects of urban tunnel drilling as lifelines on adjacent structures and render the results in the form of a diagram.
    Keywords: Tunnels, Lifelines, Adjacent structures
  • Implementing IWRM in Iran Recommendations Based on Global Experiences
    Abbasali Tayefi Nasrabadi, Atefeh Dehghan Touranposhti Pages 17-22
    IWRM is an empirical concept which has been founded on the experience of water practitioners. In other words, it is not a scientific theory to be confirmed or rejected. In turn, it is a set of guidelines derived from conventional understanding of key elements of water management. Experience shows that the countries and governments who start reforms in water sector, focus on policy making, and law/regulation developing in the first place. Some challenges of IWRM implementation pertain to the integrity and the extent on the integrity. Ideally speaking, the implementation of IWRM required the integration of all aspects. In order to achieve this, coordination is the first step. IWRM implementation might take several decades to reach the point at which one can claim the water resources management is being done in accordance with principles. The pace of IWRM implementation is developing countries is slow since these countries have poor institutional capacity for change. IWRM implementation requires balancing the conflicting objectives. Having stakeholders involved is also crucial for carrying out the IWRM approach and its effectiveness. Active, non-governmental organizations or any other civic bodies are also required for the negotiations between inter-sector and stakeholders at various levels, to take place.
  • The Effect of p-delta 21-Storey Structure in the Variable Arrangement of Lateral Stiffness
    Javad Chegini Pages 23-30
    In recent years, high-rise construction has been rising. A big challenge for engineers and executives in the construction of these structures is the stability of the structures against earthquakes. And this requires the development of appropriate arrangements for structures under lateral system and are braced system. And this requires the development of appropriate arrangements for structures under lateral system and are braced system. Hence, we decided to evaluate the geometry and arrangement of lateral system for 21-storey of steel structures in two main types do. Also the two groups design 6 model geometry lateral bracing system and mega bracings, with and without consideration of P-delta effect for each of the models we will see this, What role will this effect essentially on the response of structures. And in the end, will have an interpretation of the results.
  • Concrete Debris Recycling, Environmental and Economic Effects
    Ali Binaei Haghighi, Leila Shahryari Pages 31-35
    In this paper, first we identify the destruction ways of concrete constructions and the benefits of waste management and the plans to recycle the concrete debris were investigated and it was concluded that the existence of plans to recycle the concrete debris could lead to big economic save ups and by recycling these debris we can create affordable ways for concrete making centers. By the way, by increasing the recycling of such this debris, we can reduce the use of natural resources and help the environment.