Civil engineering materials refer to all kinds of materials used in civil engineering. Engineering materials are the material basis of civil engineering. The performance and quality of engineering materials directly affect the basic requirements of firmness, applicability, economy and aesthetics of engineering. In the civil engineering cost, the material cost accounts for a large proportion, generally about 60%. If we can use the building materials economically and reasonably, reduce the loss, we can reduce the project cost and improve the economic benefits.
In the process of engineering design and construction, it is bound to be restricted by the variety and performance of engineering materials, and the emergence of new materials promotes the development of architectural and structural forms, the improvement of structural design methods and the innovation of construction technology. The progress of material science and technology promotes the development of building engineering technology; the emergence of light and high strength materials promotes the development of modern buildings to high-rise and large span. With the development of new thermal insulation materials, waterproof materials, sound-absorbing materials and various decorative materials, the functions of buildings have been improved.
All buildings and structures are made of different materials. Materials with different properties play different roles in various parts, such as structural materials should have required mechanical properties; roof materials should have thermal insulation and impermeability; ground materials should have wear resistance; materials exposed to atmospheric environment for a long time should be able to withstand wind, rain, sunlight, freezing and so on, that is to say, they have good durability. Mastering the nature of civil engineering materials is the basis of scientific design and construction.
Civil engineering materials can be divided into narrow sense of civil engineering materials and broad sense of civil engineering materials. In a narrow sense, civil engineering materials refer to all materials directly used to build civil engineering entities, which is also the content of this book. In a broad sense, civil engineering materials refer to all the materials used in the process of civil engineering construction.
前 言
土木工程材料是指在土木工程中使用的各种材料的总称。工程材料是土木工程的物质基础。工程材料的性能和质量直接影响到工程的坚固、适用、经济和美观等方面的基本要求。在土木工程造价中,材料费所占的比例很大,一般在 60%左右。若能经济合理地使用建筑材料,减少损耗,就能降低工程成本,提高经济效益。
在工程设计和施工过程中必然要受到工程材料在品种和性能等方面的制约,而新型材料的出现又促进建筑和结构形式的发展、结构设计方法的改进和施工技术的革新。材料科学技术的进步推动了建筑工程技术的发展;轻质高强材料的出现,推动了现代建筑向高层、大跨度发展。新型保温绝热材料、防水材料、吸声材料以及各种装饰材料的不断产生,使建筑物的各项功能得到了提高。
所有的建筑物、构筑物都是由不同的材料建造而成的。不同性质的材料在各个部位发挥着不同的作用,如结构材料应具有所需要的力学性能;屋面材料应具有绝热、抗渗性能;地面材料应具有耐磨性能;对于长期暴露于大气环境中的材料,要求能经受风吹、雨淋、日晒、冰冻等,即具有良好的耐久性。掌握土木工程材料的性质是科学设计和施工的基础。
土木工程材料可分为狭义的土木工程材料和广义的土木工程材料。狭义的土木工程材料是指直接用于建造土木工程实体的所有材料, 这也是本书所要介绍的内容。广义的土木工程材料是指土木工程建设过程中所用到的所有材料。
Land is the basis of human survival, is an important means of production, but also the source of all social material wealth. Nowadays, the population, resources, environment and food problems are all related to land. Reasonable planning, development and utilization of limited land resources to realize the sustainable development of society and economy have become an important topic of concern of governments all over the world and the focus of academic circles. China is the largest developing country in the world with a large population. The per capita land, cultivated land, woodland and grassland are 0.84 Hm2, 0.11 Hm2, 0.11 hm2 and 0.25 Hm2, respectively, which are only 60% - 80% of the world’s average level of similar land use, ranking 120th, 114th, 120th and 84th in 160 countries in the world. With the development of social economy and the continuous growth of population, the contradiction between people and land in China will be increasingly acute. Therefore, it is very important to cherish and reasonably utilize extremely limited land resources and coordinate the relationship between people and land. Since China’s reform and opening up, urban and rural development is in the process of scale expansion, which has induced many contradictions and conflicts. The contradiction between limited land resources and unlimited development needs will exist for a long time in China’s social development. Economical and intensive land use is the way to solve the problem in this state, but it is not the ultimate goal to use land economically and intensively. The ultimate goal is to make efficient use of land, promote development and ecological harmony. For a long time, China’s economic development is mainly driven by the extensive mode of cheap land and cheap labor force, resulting in the low degree of land intensification, and the scale of construction land is close to the future index. However, construction land still plays an irreplaceable role in promoting economic development. The sustainable use of construction land will exist for a long time with the development of human society. At present, it is not enough to pay attention to the utilization and benefit of the stock land. Only by making the stock land play a revolutionary role in the transformation of the development mode is the foundation that the developed regions should set an example for the national development strategy.
前 言
土地是人类赖以生存的基础,是重要的生产资料,也是一切社会物质财富的源 泉。当今世界所面临的人口、资源、环境和粮食等几大难题,无一不与土地相关, 合理规划、开发和利用有限的土地资源,实现社会、经济的可持续发展,已成为世 界各国政府所关注的重要议题,也成为当今学术界关注的焦点。我国是世界上最大 的发展中国家,人口众多,人均土地、耕地、林地和草地分别为 0.84hm2、0.11hm2、 0.11hm2和 0.25hm2 ,仅为世界同类用地平均水平的 60%~80%,在全世界 160 个国 家中分别位居第 120、114、120 和 84 位,而随着社会经济的发展和人口的继续增长, 我国的人地矛盾将日趋尖锐。因此,十分珍惜、合理利用极其有限的土地资源,协 调人地关系显得尤为重要。 中国自改革开放以来,城乡发展均处于规模扩张过程,诱发了众多的矛盾与冲 突。有限的土地资源与无限的发展需求之间的矛盾将会在中国社会发展中长期存在。 节约、集约用地就是在这种状态下所产生的解决问题的办法,但节约、集约用地并 不是最终目的,高效利用、促进发展、生态和谐才是终极目标。长期以来,我国经 济发展主要以廉价土地和廉价劳动力的粗放式带动为主,致使土地的集约化程度较 低,并使建设用地规模量迫近未来的指标。但建设用地在促进经济发展中依然起着 其他资源所不能替代的作用,建设用地的永续利用将伴随着人类社会的发展而长期 存在。目前,仅仅关注存量土地的利用与利用效益是不够的,使存量土地在发展方 式转变中起到革命性的变革作用,才是发达地区应该为国家的发展战略起表率作用 的根本。
我国是矿业大国,自改革开放以来,随着工业化、城镇化、现代化进程的不断加快,社会经济发展对矿产资源的刚性需求不断加大,地质勘查任务增多,矿业开发活动加剧,对矿山地质环境的破坏越来越严重,以致矿山地质环境治理的速度赶不上破坏的速度,恢复治理任务艰巨而繁重。
矿山是我国环境保护的重灾区,也是环境保护工作相对薄弱的领域。目前,矿山环境问题越来越突出,严重影响和制约着矿业自身乃至整个国民经济的可持续发展。矿业兴衰在经济危机中表现出的影响滞后性和影响长远性已被人们所认识。矿山环境问题已引起国务院和生态环境部、自然资源部等相关部委的高度重视,相继颁布了一系列的法律、法规和规定。
矿区的生态修复已成为我国生态环境建设的重要组成部分,通过对废弃矿区的生态修复,能够有效改善生态环境;同时结合土地整治,对土地资源进行综合利用,缓解人地资源的矛盾。通过矿区的生态修复工作,配合我国社会主义新农村建设,促进绿色 GDP 的增长,实现循环经济,构建和谐社会。
被称为“社会科学之皇后”的经济学,已经越来越引起人们的重视,对其理论的了解,已经成为掌握其他各相关经济学知识的基础和分析现实经济现象的工具。
经济全球化的历史趋势,自然而然地提出了中国经济学现代化的问题。中国经济学的现代化即在吸收西方经济学合理内核的过程中注重立足于中国国情并对其进行了“去粗取精、去伪存真”的制作加工,在解决我国实践中面临的各种问题时,大胆借鉴了西方发达国家反映市场经济一般运行规律的理论与先进方法。
在长期的市场经济学教学过程中,我们深切地感到,研究市场经济问题,应该在尊重中国国情的基础上,大胆地吸取和借鉴西方国家发展市场经济先进的管理经验和有效的运作方法。因此,在编写这本教材时,我们重点分析和讲述现代市场经济的基本概念、基本原理和规律,不再过多地进行社会主义市场经济与资本主义市场经济的比较研究,力求做到求同不存异、求新不照搬,并力求阐述简明扼要、体系内容完整、文字深入浅出。
中国的社会经济能否成功地从一个计划体制的工业和农业经济转型为知识经济, 关系到中国能否实现第三步走的战略目标。 发达高收入国家是在完成了工业化、城市化和服务业化的条件下进入知识化时代的。但是,绝大多数发展中国家,包括中国,是在远没有完成改造传统农业,实现工业化和城市化,服务业化发展水平比较低下的条件下面临知识化挑战的。
随着我国城市化进程的飞速发展和新农村建设进度的不断推进,国家和地方政府对市政刚才建设的重视和投资力度也在逐步加大,市政工程行业也随着经济的迅速增长而快速发展。市政工程建设项目中的施工管理也取得了显著的成绩,但是目前质量事故、费用超支、工期拖延和各种安全事故等问题依然存在,特别是近几年来出现的数起重大工程质量事故,给国家和人民的生命财产造成了巨大损失,而这些事故几乎都是施工管理不规范造成的。
加强市政工程施工技术有利于维护市政工程项目,有效的管理市政工程项目,市政工程建设涉及方面非常广泛,对国家和人们非常有利。对于施工技术的前期优化和策略管理工作,一定要制定详细的方案,把先进的科学技术完美的结合起来,通过科学技术方法,把施工中出问题的针对解决,这样才可以保证市政工程建设的按时完工,提高整体施工建设的工作效率,提高经济利益。
对市政工程中的施工技术工作进行优化,不仅可以提升市政工程的质量,还可促进整个城市的建设发展,所以一定要不断的提高技术力量,根据实际情况,结合当地地区的特点,与现代化相结合,确保整体工程的经济效益,保证工程的质量,可以更好的发展城市建设,提高居民的生活环境。