نشریه عمران و پروژه
سال دوم شماره 12 (پیاپی 22، اسفند 1399)

In the last two decades, the increase in quality and strength in new concrete technology has grown significantly. One of the new generation concretes that is considered as a powerful and efficient concrete in the construction industry today is fiber concrete, which has improved mechanical properties such as higher tensile strength and even improved compressive strength. This concrete, which has a compressive strength in a range of 15 to 200 MPa, is mainly used in the construction of structures resistant to dynamic loads and thin walls, and its use in new construction projects has a high potential. In the present study, the role of human hair as fibers in reinforcing concrete and the characteristics of hardened concrete have been investigated and its details have been studied from the point of view of mechanical characteristics. For this purpose, 6 types of mixing schemes with different percentages of crushed hair (0-1-2-3-4 and 5% by volume) were considered and the desired mixtures were reached and molded with the help of lubricant. Tests of compressive strength, tensile strength, modulus of elasticity, and water absorption were performed to evaluate the mechanical and physical properties of concrete. The results of compressive strength of the samples showed that 2% of the consumed hair caused a 9.8% increase in compressive strength compared to the control design. Tensile strength also increased by 34.3% in the same percentage of consumption compared to the control design. The modulus of elasticity increased by 8.65% in 1% of hair consumed and then decreased. Water absorption had an increasing trend and in 2% consumption, showed a 24.2% increase compared to the control.

Road maintenance is considered as one of the major and important factors in the pavement management system (PMS). Regarding the type of data collection in this study, the observation method based on index PCI (Pavement Condition Index) according to ASTM D6433 standard was used. Research aims to assess the priority of road maintenance using the Pavement Condition Index (PCI). Locations for this research were the roads at the EMU campus to length 10 km in Northern Cyprus and 16 road segments were taken from each district. There were 9 distress types that had been recorded. We intend to add to this project a new dimension by analyzing the EMU campus road. The results of the research as obtained from the method of PCI and prioritization can be identified as follows: five road segments are in good condition, four are satisfactory, six are in fair condition, one is in a failed condition, and one road segment is in serious condition. In total, 15 of 16 road segments are in stable condition. The result generally indicates that the road was 80.63% in satisfactory condition. In general, it can be concluded that road pavements are constantly exposed to various types of stresses such as heavy traffic load, temperature, humidity and bed soil displacement, which over time lead to damage such as cracks in the Alligator cracking, Patching and Utility cut, Block cracking, Long and Trans cracking, Rutting, and Asphalt Bleeding are in the pavement. Patching and Utility cut, Alligator cracking and Long and Trans cracking were assessed as the most severe.

Recently, with the advent of nanotechnology and the manufacture of nanoparticles, a huge change has taken place in the functional demands of materials. The role of the pavement surface layer, which is made of asphalt mixtures, in the performance of pavements is inevitable. The use of nanotechnology in the construction of transportation infrastructure is roughly equivalent to the human effort to send humans to the moon in the 1960s. In 2005, the idea of building asphalt for highways that could repair themselves seemed far-fetched to many. Therefore, the asphalt industry still needs a transformation so that people can see the possibilities of nanotechnology and understand its benefits. Due to the compositional nature of the asphalt mix, the potential for improvement in the mechanical properties of asphalt using nanotechnology is very important. Modification of nanomaterials began with engineering changes in the molecular structure of asphalt with the aim of influencing the properties of these materials. Nanoscale modifiers can react with bitumen to change the chemical and molecular structure of the bitumen, which can lead to better asphalt performance. In recent years, the use of nanoparticles in changing the behavioral and chemical properties of asphalt has been considered by researchers and researchers have conducted numerous experiments to study these properties in order to improve the properties of asphalt mixtures made with nanoparticles, but this science still needs To more extensive research in order to achieve more comprehensive and accurate results. This paper reviews the studies on the effect of different nanoparticles on the production of cold asphalt in factories produced with emulsion bitumen.

Infrastructure and development projects in any country constitute the infrastructure and development of that country. In the implementation of these projects, financing is an important and primary concern due to the lack of infrastructure and infrastructure in the country on the one hand and the lack of capital resources on the other hand, capital has an undeniable role in this. Financing projects is one of the most common investment methods in any country. Undoubtedly, how and how to finance the projects for each level of existing institutions depends on the nature of the project. Paying attention to financing has a high share in solving the problems of financing and launching projects. Therefore, the purpose of this study is to rank the methods of financing from external sources in construction projects. The present study is applied in terms of purpose and descriptive-survey in terms of the nature of the method. In order to collect data, a questionnaire based on multi-criteria decision making method (network analysis method) was used, which was completed by five senior financial engineering experts with at least 10 years of experience in financing projects of construction companies in the west of Tehran. The collected data were analyzed by Super Decisions software. The results of financing ranking showed that international loans with a relative weight of 0.314 ranked first, BOT contracts with a relative weight of 0.21 and finance with a relative weight of 0.171 took second and third place. Findings of the study show that in general, the criterion of higher rate of return with a relative weight of 0.64 than the criteria of lower risk with a relative weight of 0.26 and a ceiling of more funds with a relative weight of 0.1 is of higher importance in financing from external sources in the project. Have civil engineering and should be given more attention.

This research aims to analyze road construction workshops based on measuring the safety atmosphere of the work environment based on the Nordic questionnaire in the workers of active workshops in Kerman province. The research method has been descriptive-analytical. The statistical population of this study includes all workers of active workshops in Kerman province. After explaining the work process, they were asked to complete the standard questionnaire for measuring the safety of the Nordic safety atmosphere, which includes 7 main dimensions. The sample size is 164 workers in the road construction field. The available sampling method is also used to determine the sample size. To collect information, the standard questionnaire of Nordic safety atmosphere (2006) was used. Questionnaire 7 dimensions of management safety and commitment, management, and safety management, management safety justice, employee safety commitment, safety priority and non-acceptance of employee risk, education and training Learning to trust safety and reliability covers the safety of the immune system and consists of 50 items. To analyze the data, SPSS software version 23 has been used. The results show that the average scores of workplace safety atmosphere and some dimensions, namely management safety and power, employee safety commitment, safety priority and non-acceptance of employee risk, training and learning and confidence in safety ability are desirable and management safety priorities and commitment, management safety justice and confidence in safety efficiency are not desirable.

Project management techniques such as project retrieval and evaluation and the critical path method help audit managers to be able to allocate audit staff well to related tasks and carry out auditing as planned. Project retrieval and evaluation techniques and the critical path method simplify An audit project plan helps managers a lot and shows short-term and long-term goals to employees and managers. Therefore, managers can better use these techniques to plan for employees and assign them to new tasks, and on the other hand, this They will also be able to modify the audit program more efficiently and accurately.