Model essay on civil engineering materials 1: teaching summary of civil engineering materials course;
By studying? Civil engineering materials? Courses should not only enable students to learn knowledge, but also exercise their abilities and broaden their horizons; Not only mastered the knowledge of this course, but also laid a good foundation for the study of other professional courses. So, do it right? Civil engineering materials? Teaching is of great significance
Keywords: civil engineering; material
First, classroom teaching
(A) highlight the key points
? Civil engineering materials? It is impossible to explain all the course contents in a limited time, and we should prioritize and highlight the key points according to the nature of our major. Take Civil Engineering Materials [1] edited by Cheng et al. as an example, the key contents of this course are: introduction, chapter 1 (basic properties of civil engineering materials), chapter 2 (inorganic cementitious materials), chapter 3 (cement concrete), chapter 4 (mortar), chapter 6 (steel for civil engineering) and chapter 7 (asphalt). Through the study of introduction, students can have a general understanding of civil engineering materials. Civil engineering materials? Have a general understanding of this course; The first chapter makes students understand the basic properties of civil engineering materials, including physical properties, mechanical properties and durability, and at the same time understand the basic theory of material science, that is, the composition, structure and structure of materials and their relationship with material properties; Chapter two, chapter three, chapter four, chapter six and chapter seven respectively explain the performance and application of several most commonly used civil engineering materials in engineering. Chapter five (building materials), chapter eight (wood), chapter nine (synthetic polymer materials) and chapter ten (building functional materials) are the contents of students' autonomous learning, but teachers should guide and encourage students to think positively and dare to ask questions in the process of autonomous learning. In classroom teaching, the content of key explanations should be thoroughly explained, so that students can master it in a down-to-earth manner and learn something; Avoid covering everything and not seeking solutions. Moreover, with the key content as the basis, students will not find it difficult to study other chapters independently. The organic combination of key classroom explanations and students' autonomous learning not only helps students to master systematic theoretical knowledge, but also gives students a space for autonomous learning, which is conducive to cultivating students' questioning spirit and ability to solve practical problems, and developing students' imagination and exploration consciousness.
(2) Scientific explanation
? Civil engineering materials? The content of the course is relatively loose, and it is easy to feel straightforward or even boring when explaining; If carefully arranged and scientifically explained, the effect will be very different. For example, ordinary portland cement includes portland cement, ordinary portland cement, slag portland cement, pozzolanic portland cement, fly ash portland cement and composite portland cement. If you talk about cement one after another according to the textbook, students will feel repetitive, piled up, messy and even confused. Therefore, this part should be scientifically integrated, focusing on the mineral composition, hydration and coagulation hardening process, technical properties and so on of portland cement. When introducing portland cement mixed with active substances, it is necessary to grasp the potential activity of active mixed substances and the secondary hydration reaction of cement mixed with active mixed substances, and then give the * * * characteristics and personalities of various cements by comparison, so as to make the contents compact, the context clear and easy for students to master. Knowing the similarities and differences of technical performance, it is easy to further master the engineering application of various cements. For another example, in modern cement concrete technology, additives have become an important part of cement concrete. Therefore, for the systematic and complete content, ordinary textbooks (such as literature) will? Additives? Put it in? What are the components of ordinary concrete? Let me introduce you. However, additives are used to improve the performance of concrete. If you don't know the performance of concrete, it is difficult to deeply understand the role of additives. So when teaching, you should make appropriate adjustments. Additives? Release? What are the main properties of concrete mixture? And then what? What are the main properties of hardened concrete? It will be more convenient for students to understand and remember the course content in the future. In a word, it is very important to organize and explain the course content scientifically. Civil engineering materials? Classroom teaching plays a multiplier role.
(C) the combination of theory and practice
First of all, from the most familiar reality of life. Civil engineering materials are closely related to real life. In fact, everyone has accumulated a lot of relevant experience in real life, but they don't know the truth because they don't have professional knowledge. For example, the damaged cement mortar floor needs to be watered for a period of time after being repaired with cement mortar. I believe many people have seen this practice, but not everyone knows why. When explaining the process of hydration, coagulation and hardening of cement, students will suddenly realize that this is maintenance, and let students know that maintenance needs a certain temperature, humidity and time in time. In this way, students' direct experience from life and theoretical knowledge in books are combined to eliminate students' strangeness to the course and stimulate students' interest in learning. Secondly, a large number of engineering examples are listed. Typical engineering examples are the most effective way to understand and digest theoretical knowledge, pay attention to the engineering application background of materials and avoid explaining materials in isolation from engineering. For example, when it comes to the durability of concrete, for example, the pier of Beijing Sanyuan overpass happened in some places less than two years after it was built? Herringbone? After analysis, it is considered that the main cause of cracks is alkali-aggregate reaction; Example 2: The Chernobyl nuclear power station in Ukraine, due to the leakage of reinforced concrete structure, caused a large area of radioactive pollution, and the ecological environment was seriously damaged. In addition, it can also be explained by numbers. In industrialized countries, more than 40% of the total investment in the construction industry is used for the repair and maintenance of existing structures, and less than 60% is used for new facilities? . Through a large number of examples, let students realize the importance of concrete durability, and understand that the premature failure of many concrete structures is not due to insufficient strength, but insufficient durability. Finally, attach importance to experimental teaching. What is the experimental class? Civil engineering materials? As a very important teaching link of this course, experimental teaching is a good supplement to classroom teaching. In the experimental class, students have an intuitive understanding of the materials learned in books, further understand the properties of materials, and improve their ability to apply materials in the process of doing their own experiments. At the same time, through experiments to verify the basic theory, learn experimental methods, cultivate scientific research ability and rigorous scientific attitude.
(D) Pay attention to the new progress of the discipline
Textbooks are the foundation and foundation of teaching, but it takes time to update them, and the development of civil engineering textbooks is very rapid. Therefore, in the teaching process, we should pay close attention to the latest progress of civil engineering materials research and engineering application, and supplement it to teaching in time. At the same time, with the emergence of new materials and technologies, the quality standards of related materials and related design and construction specifications will also be updated, and this part should be added to teaching in time. This will help students to keep abreast of the development of the discipline, broaden their professional horizons, cultivate innovative consciousness, stimulate the spirit of exploration, and improve engineering quality and awareness.
Second, homework after class.
Homework after class has played a very good role in consolidating and supplementing classroom teaching. Through homework, students can better digest and understand what they have learned in class, and they can flexibly apply what they have learned. In this course, part of the homework comes from the review questions at the back of each chapter of the textbook, which requires teachers to closely follow the key and difficult points of classroom teaching and select from them, such as particle gradation of concrete aggregate and mix design of ordinary concrete. Teachers should carefully correct and summarize their homework, so that students can really master their homework instead of doing it for the sake of doing it. The other part of the assignment is synthesis and discussion. Such as Civil Engineering Materials edited by Cheng and others? Open discussion? Part, this part is forward-looking and can guide and inspire students to do some exploratory work. That is, let students choose what they are interested in, and consult the literature around this content, think deeply and discuss freely. Broaden students' horizons and cultivate their awareness of scientific research.
Three. Concluding remarks
By studying? Civil engineering materials? Courses should not only enable students to learn knowledge, but also exercise their abilities and broaden their horizons; Not only mastered the knowledge of this course, but also laid a good foundation for the study of other professional courses. So, do it right? Civil engineering materials? Teaching is of great significance
refer to
1, quantitative evaluation of bidding risk of international large-scale civil engineering contracting projects, Rui Liu Tianjin University 2003-06-0 155.
2. Research status and prospect of bolt support mechanism in civil engineering Jia, Geotechnical Engineering, August 2003 -3053.
Model essay on civil engineering materials ii: summary of the application of intelligent materials in civil engineering;
Key words:
1 application of intelligent materials in civil engineering
Monitoring of 1. 1 optical fiber in concrete materials
As an optical communication medium, optical fiber material has the greatest advantages of fast transmission speed, low signal attenuation and strong parallel processing ability, and is often used in high-demand communication transmission. Optical fiber and optical fiber sensor are mainly used to monitor the solidification of concrete in civil engineering. The biggest disadvantages of concrete structure are weak tensile strength and easy corrosion of internal steel bars. In the process of large-scale pouring, cracks appear in concrete blocks due to the temperature difference between inside and outside the concrete structure. In this case, optical fiber, as a sensing element, is embedded in the concrete structure to detect, diagnose and predict the dangerous factors that may damage the concrete structure, such as strength, temperature, deformation, cracks and vibration. Furthermore, if the control elements can be connected to the information processing system and smart materials such as shape memory metal can be introduced to form a complete control system, the adaptive function of concrete materials can be realized? This is the frontier subject of intelligent material structure system in civil engineering.
1.2 piezoelectric material
Piezoelectric materials generally refer to crystal materials with voltage at both ends after receiving pressure. The application of piezoelectric materials in civil engineering mainly includes static deformation control, noise control, earthquake resistance and wind resistance of structures. The traditional use method of piezoelectric materials is to sense the vibration of the structure through piezoelectric sensing elements, and realize the sensing and early warning of vibration by using the output results of sensors. On this basis, the appropriate control algorithm is used to control and quantify the input of piezoelectric body, so as to control the structural vibration, which is the research frontier of piezoelectric smart materials at present. With the development of research and technology, the application of piezoelectric intelligent structures in civil engineering should be more and more extensive.
1.3 piezomagnetic material
The application of piezomagnetic materials in civil engineering mainly includes magnetorheological materials and magnetostrictive materials. Based on the principle of magnetorheological materials, when the magnetic field strength is higher than the critical strength, magnetorheology changes from liquid to solid in a short time. Between solid and liquid, according to the characteristics of magnetorheological fluid, it has the characteristics of fast, controllable and reversible, and the energy needed to control the fluid characteristics is low. Therefore, magnetorheological fluid is usually used as the main material of power device in intelligent structure. Based on this, magnetorheological materials can be used in high-rise building structures to realize semi-active earthquake control. Magnetostrictive materials have attracted great attention in recent years because of their broad potential application prospects. Magnetostrictive materials have a strong magnetostrictive effect and can be reversibly converted between electromagnetic and mechanical. This characteristic makes it suitable for high-power ultrasonic devices, sonar systems, precise positioning control and many other fields.
1.4 shape memory alloy
Shape memory alloy is a kind of smart material with shape memory effect. Shape memory alloy can stimulate its shape memory effect under certain conditions after its shape changes. In this process, the material produces recovery stress higher than 700 MPa and recovery strain of about 8%, which has strong energy transmission and storage capacity. Based on this characteristic, the biggest use of shape memory alloy in civil engineering is to realize the self-diagnosis of structure, increase the toughness and strength of materials and enhance the adaptive control of materials. Shape memory alloys can also be developed into intelligent actuators to control structural deformation, cracks and vibration. Shape memory alloys have high phase transition resilience. Combined with this feature, a passive energy dissipation control system of shape memory alloy can be developed to realize pseudo-elastic phase change performance, which can be used for energy dissipation and seismic passive control of civil engineering structures. At present, in the practice of civil engineering, the passive energy dissipation control system of shape memory alloy is usually installed in the position where the structure is greatly affected by the earthquake, such as the floor or bottom of the structure. The deformation of the floor of the structure is sensed through the energy dissipation system, and then the earthquake energy is consumed.
2 Advantages and limitations of smart materials
Intelligent materials used in civil engineering have the abilities of information feedback, self-diagnosis, self-repair and self-adaptation. Practice also shows that the application of intelligent materials in practical civil engineering makes the engineering structure have the characteristics of high strength and durability, and can intelligently execute instructions and adapt to the changes of external environment. The above materials, such as optical fiber, shape memory alloy, piezoelectricity, piezomagnetism, etc., are all high intelligent composite materials in nature, and their biggest limitations are high use cost and high manufacturing cost. This shortcoming makes the application of intelligent materials limited to high-grade and high-standard construction projects, and the application of intelligent materials in ordinary residential buildings is still in the foreseeable future. In addition, the application of intelligent materials needs the support of corresponding technology and supporting materials and equipment, and the requirements for construction technology and technology are higher in construction. Therefore, the application of smart materials can not be widely popularized in all directions at present, but smart materials may be the research and development direction of civil engineering materials in the future.
3 Conclusion
To sum up, the application of intelligent materials in civil engineering makes up for the weakness of traditional building structures in adapting to the environment, and makes the building structure change from manual detection to self-detection, adjustment and adaptation. At present, the application of intelligent materials is limited to a few high-demand and high-standard construction projects. The scientific research on smart materials and related technologies and supporting equipment is the premise and foundation for the wide application of smart materials and civil engineering structures in the future.
refer to
1. Reflections on the Practice Teaching Reform of Civil Engineering Major in Xiulan Hu: Zhu Ming Bridge; Sara; Cheng; journal of architectural education in institutions of higher learning