1.Foreword

China has insufficient natural resources as compared with its large number of population. Its possession rate per capita of coal, oil, gas, arable land, water and forest just account for 1/2, 1/9, 1/23, 1/3, 11/4 and 1/6 in terms of average value in the world. Its cultivable land ( high-yield land is less) only makes up 13% of the territory and the arable land per capita is only 1.43 mu, and the stand-by resources are in serious shortage. China has a shortage of water resource with possession rate of 2200 m3 per capita. Some areas in the north and west parts of China are internationally recognized in badly need of water. 2/3 of 600 cities are facing insufficient water supply, and 1/6 cities thereof are in serious shortage of water. China’s oil reliance on overseas supply exceeds 30%, and its reserves of key mineral resources is less than (1). With the fast development of the Chinese economy, China will consume more and more resources as causes more unfavorable impact.

Building industry is one of the key industries in national economy. Its material consumption makes up 15% of total material consumption. The energy consumption in construction accounts for 28% of total energy consumption. The pollution caused by building-material production and construction-related activities accounts for 34% of total pollutions. Moreover, utilization ratio of energy and resources is very low in building construction and utilization, and energy consumption per unit in construction is 2-3 times higher than that in developed countries under the same climate circumstances, 10-25% more in steel consumption, and 80 kg more cement consumed per cubic concrete, etc,. In recent years, annually completed building area reaches 1.6-2 billion sqm, and by 2002 completed building area comes to nearly 40 billion sqm, most of which are high-energy-consumption buildings. The most of newly-constructed buildings belong to high-energy-consumption buildings.

Therefore, it is strongly encouraged, in building construction, to save land, save energy, save water, save materials and protect environment, and this encouragement is playing a key role in the sustainable development of Chinese economy, and it is also the key connotation of green building in China. So the Chinese government sets up related research, enact concerned regulations and laws, highly advocates green buildings featuring above-mentioned “four savings, one protection”. In 2004, the Ministry of Construction and the Ministry of Science & Technology began to organize implementing the science & technology research project of “Key Technical Research of Green Building” which was planned for“ Tenth Five Year Plan”, and the priority of the research was to establish evaluation standard and technical guideline of green building in China, to develop key technology and complete equipments which conform to the standards of green building and possess self-owned intellectual property rights. The priority of the research was also to build up, by systematic combination of technology and demonstration of the project, a self-renovation system and a research & development base in terms of core technology of Chinese green building. In the second half of 2004, the Ministry of Construction officially established the “National Prize for Renovation of Green Building” which indicated that China had entered into the stage of popularizing the green building. Soon in Dec. 2005, the Ministry of Construction published “The Technical Guideline of Green Building”, and in March 2006, the Chinese government enacted “The Evaluation Standard of Green Building” which became the standards to be followed in evaluation of green building. The construction and development of green building will be a prevailing trend in the building industry in China.

CSCEC has been attaching importance to technical development in green building. Beginning from the end of 1980s, CSCEC participated in the energy-saving building project initiated by the Chinese government and the British Ministry of Construction, it has done a lot of research and development works since then on designing and construction of green buildings and developing green building materials. Here is a brief introduction as follows.

2. Green Building Design
Whether a building is green or not shall be determined by the design.
All building design institutes of China Construction have rich experience in this respect and would like to brief it hereby.
2.1 High-rise building with reinforced concrete blocks
As normal bricks are forbidden to be used in some of the cities in order to protect the plowland, and as the existing knowhows of multiple building blocks can not satisfy the requirments of energy and material saving, China Construction’s Northeast Design Institute started 10 years ago the research of technology of reinforced concrete blocks for high-rise buildings, and successfully worked out the high quality mortar and hole-filling concret for making up new blocks; through numerous tests and analysis, basic intensity data of blocks have been acquired and after further experimentation and credibility analysis on the block wall, a shearing force wall’s weight-bearing calculating pattern has been established, thus resolved the problems of earth-quaking resistance.And, based on the trial buildings with reinforced concrete blocks, technical specifications had been compiled to insure the design and construction quality, which had also been adopted by the State Standards “Specifications for Block Structure Design”GB50003-2001.
Highrise reinforced concret blocks are similar in bearing nature with reinforced concrete itself. When the wall thickness is 190mm, the building using blocks can reach a height of 20 storey, which is rather appicable and economic, while the cost can be reduced 10%-20%, steel bar saved 30%-50% and the construction period shortened 25%. That is why we say it is of green building structure.
2.2 The compound insulation structure design technology for the Southern new structure requirement
CSCEC Southwest Building Design Institute is located in Southwest China, thus well known of the enerny-saving technology for buildings under the southern climate. The recent developed “The compound insulation structure design technology for the Southern new structure requirement” has resolved the all-in-one problem of structure bearing, heat preservation,heat insulation,and sound insulation, reduced wastage of cement and steel, making contribution to energy-saving and material-saving and to a cozy coditions inside the building under southern climate.
2.3 Light Steel Structure Energy-saving House Technology
Light steel structure energy-saving house has the character of green building: the structure is light—about 30% lighter than brick-concrete structure; and 20% lighter than concrete shearing force wall structure. Thus reduce the excavation quantity of foundation, avoiding mass underground water-drawing. It is good in energy saving too, as light standard energy-saving pre-fabricated wallboard can be used, it has a very good heat preservation, about 50% up compared to common bricks. It is also good to environment protection when conducting construction, as a large quantity of sand,stone and mortar can be reduced and all steel materials can be recycled when dismantlement time comes.

China Construction Technical Center are taking a complex research on, but not limited to,light steel structure energy-saving houses, which envolves supports, shearing force wall; off-center supports under earthquake condition; typical joints for light steel house and its anti-earthquake nature; heat preservation and energy-saving technology on floor,wall and the house; rusty-proofing and insulation materials for doors and windows; solar-energy knowhows,water and energy-saving applicable technology; ventilation technology; natural lighting, indoor illimination; yawp and enviornment control and etc.
3. Green Construction Knowhows
3.1 Plain concrete facing
Plain concrete facing needs no plastering, spraying, dry hanging or other decoration, thus it saves resources. And its nature has been improved in terms of freez-resisting,insulation and wearing. To use plain concrete is also good for human health, since decoration materials are reduced.
3.2 TCC Building Heat-Preventing Formwork System
Energy-saving takes an important position in green building technology. Feb.23, 2005, Mr.Chou Baoxing, Vice Minister of Construction Ministry set up goals for two stages of building energy-saving: Stage one is that upto 2010, one third of the new buildings of the country shall reach the standard of green and energy-saving, while the total energy consuming of construction for the main cities and towns shall reduce 50%, some of the super-large cities such as Beijing shall reduce 65%. Stage two, when 2020, the whole society’s building energy saving shall reach the goal of 65% reduction.
Thermal insulation of peripheral wall is one of the important processes in energy-saving buildings. The updated insulation techniques leads to more effective thermal insulation. China has evolved insulation techniques from inner side of the wall, midst of the wall to the prevailing method of outer side of the wall. Since 1980s, many developed countries have made efforts in developing wall-insulation techniques and new building system, which makes the permanent thermal-insulation materials available by combining permanent formwork, which is made of thermal-insulation materials, concrete and other filling materials. This technique not only leaves out separate thermal-insulation procedure and shorten working period but olso ensures that the thermal-insulation materials, structure and decoration materials can be combined effectively and the thermal-insulation materials and structure can be integrated as a whole.
After utilizing the common advantages of new building system developed
by foreign countries, China Construction Eighth Engineering Division Co.
Ltd. worked out a applicable building system in China which is called TCC
Thermal-Insulation Building System. The operation of this system is to
use, on the side to preserve heat, the thermal-insulation board together
with special bracket as thermal-insulation formwork, which substitutes
the traditional formwork and serves, associated with traditional formwork
on the other side, as a whole formwork system. When concrete was poured
in and solidified, the structure layer combined with thermal-insulation
layer is ready after thermal-insulation formwork bracket and traditional
formwork were removed.
This system can well satisfy the energy-saving requirement for building industry in China, and it can save formworks, consume less wood, bamboo or steel due to integrity of insulation layer and formwork. The primary estimation shows that this system can save by 17.43 RMB/m2 as compared with separate thermal-insulation technique when plywood, made from wood or bamboo, as formwork is adopted, by 28.40 RMB/m2 when steel board as formwork is adopted, and 17.50 RMB/m2 when assembled-steel board as formwork is adopted. Therefore, this system has a bright future for application.
3.3 The technique of building reinforcement
From the resource-saving point of view, some old buildings in which there still remain useful value can be used safely after they were reinforced rather than being pulled down and rebuilt. In western developed countries, there are large proportion of buildings to be reinforced, and building reinforcement has become a new industry. At present, the following types of buildings in China need reinforcing: （1）buildings, constructed after liberation, approaching or exceeding their scheduled service life; （2） buildings which have defects in design due to designer’s insufficient recognition of lastingness of buildings; （3）buildings to be reinforced due to their structural alteration or their increased load caused by changed function or storey-adding expansion.
There have been some achievements in building reinforcement and renovation in China, but the level of building reinforcement and renovation in general is not so high. The technical center of CSCEC began to work on the project of The Complete Techniques of Reinforcement and Renovation of Building Structure, and to engage itself in systematical researches on the techniques of assessment and authentication of building’s safety, on the theory of designing of reinforcement, construction techniques of reinforcement and reinforcement materials of good quality and steady performance. It is expected that the technique of building reinforcement in China will be promoted to a new stage.
4.Green Construction Management
A part of green building is the green construction which has been well implemented by CSCEC. At present, the green construction covers the following aspects:
（1）decreasing the adverse impact on the environment, including the environment protection of site soil and atmosphere, control of noise impact, prevention and treatment of water pollution, prevention and treatment of light pollution, security control of surrounding areas, protection of long-lived and rare trees and cultural relics, etc.
（2）management in saving energy, water and materials. There are a lot to be improved in optimization of dewatering scheme, minimization of pumping ground-water, effective use of ground-water.
（3）treatment of solid castoff. The solid castoff on the construction site will make impact on saving energy, materials and environment. The solid castoff on the construction site should be given enough attention and treated in principle of quantity reduction, utilization as resources and innocuity.
（4）the civilization on site and people’s health and safety are important parts of green construction, and important factors to put people first and to create a harmonious and healthy atmosphere.
The realization of green construction also relies on a perfect
management system. It is China Construction First Engineering Division Co. Ltd. that was the first to work out the enterprise standard of Management Standard of Construction of Green Building, which standardizes the green construction. The project of Beijing LG Plaza, constructed by China Construction First Division Group Construction & Development Co. Ltd., was listed as model project of Olympic buildings by Research Group of Beijing Olympic Green Buildings and was taken into the book of Samples of Green Buildings which is one of national guidebooks of Assessment Standard of Green Buildings.
In addition to the general practices in the management of constructing green buildings, CSCEC Ltd. worked out The Regulation of Controlling Environment On Construction Site which was issued in June 2005. The Regulation puts forward, for different works, operation procedures, environment factors, 7 requirements for personnel, materials, equipments, procedure control and monitoring, etc, and the Regulation reflects, during construction, the control of construction in different seasons and the control of emergency and accidents. The Regulation is also conducive to environment protect for the duration of the project and to the dynamic management and control, and it provides, for advancing environment management on construction site, a detailed, precise and optimized controlling measures in the whole course of the project. It is this Regulation that is the first time to work out systematically the ration, calculating formula and method which are playing the leading and guiding role in environment protection of building industry in China.
5.Development of green building materials
Green-building’s factor is green materials, and CSCEC Ltd. has done  a lot of works in developing green materials.
5.1 General high-performance concrete
The high-performance concrete can be deemed as the concrete of high workability, high strength mixed with effective water-reducing agent and low water/gel ratio of many blending materials. The high-performance concrete is a green building material featuring its economy in energy and materials, and harmony with environment.
In addition to over-C50 high-performance concrete, CSCEC Ltd. also developed under-C50 high-performance concrete which is called general high-performance concrete as well because under-C50 high-performance concrete is, at present, popularly used on the projects. The general high-performance concrete developed by China Construction Third Engineering Bureau Co. Ltd. achieved breakthroughs in penetration of chlorine-resistant ion, conventional penetration-resistant and volume stability of concrete, and made the lastingness of general concrete possible. The experiment shows that the working life of this concrete lasts more than 50 years for marine project when the thickness of protection layer is ≥40mm, and the working life of this concrete is 30-40 years longer than other ordinary concretes with the same protection layer and under the same working situation. The use of this concrete can save more resources.
5.2 Super Fluidity Fine powder
   To produce high-performance concrete, it is necessary to blend super fluidity fine powder(SUF for short). CSCEC Ltd produces, with self-developed fine-powder-processing technique and surface-nature-changing technique, super fluidity fine powder by using industrial phosphor dregs, which is deserted in northwest of China, as basic raw material with special complex additive mixed.

Due to special material and processing, the surface of SUF is in a special status. The research shows that SUF has the super fluidity when applied in the concrete. Meanwhile, resources can be saved if SUF replaces cement. And water cement ratio may decrease to below 0.3 and the slump constant can be 260mm, and the strength can be 80-100Mpa, thus the concrete can be easily pumped. At present, only the SUF produced in this way may produce powder with surface-nature-change technique.

SUF may thin the aperture to below 500A to improve the impermeability, corrosion resistance and anti-carbonation to protect the steel bar. In accordance with the thinning of the aperture and the conductive volume estimated by the requirement of ASTMC1202, the length of service of the concrete works may extend to 120 years. The produce of SUF consumes the industrial phosphor dregs, which helps to protect the environment.
5.3 Photo catalysis
The air quality is facing challenge with the increasing Nox gas and the emission from cars and the growth of urban population. Especially with the improvement of the living standard, more and more people are doing interior decoration. More and more material with formaldehyde, ammonia is used, and acetone, benzene by the painting and wall paper threaten the health. The photo catalysis uses the catalyst to activate water and oxygen, which is similar to photosynthesis and produce the OH free radicals and reactive oxygen species. These may kill the bacteria and decompose organic pollutes to the water and carbon-oxygen, to ultimately purify the air. This is conducive to improve the air quality and protect the environment.
5.4 ISRF
With the progressing of the energy saving, the requirement will be applied in Beijing and Shanghai and the energy shall be saved up to 65%. This will be a challenge to the most energy-saving materials available in the market. Therefore, to develop new energy-saving material is necessary. ISRF developed by the First Engineering Bureau satisfies this need.

ISRF is composed of aluminum-plated film and air cushion film. Aluminum-plated film is plastic and can reflect lights. Air cushion film is to insulate heat and reduce vibration. ISRF takes advantages of the reflection of the aluminum-plated film and heat-insulate of the cushion film. It can insulate heat, moist, and sound and reflect light. It is durable and can be used as the heat-insulate layer for the wall, roofs, floor and tunnels. It will help to save energy up to 65%.
6. Other green construction techniques
6.1 1RX-II heat conduct factor detector
To evaluate how much energy a building built in the energy-saving standard can save by its design cannot reflect the deviation between the real situation and the construction progress, and cannot satisfy the requirement of the quality supervise authorities, therefore the inspect on site is necessary. The First Engineering Bureau developed 1RX-II heat conduct factor detector, and apply the theory on the site. And experiments are conducted on the brick wall, bricks and heat-insulating wall. The experiment shows that the detector is users friendly and stable and up to the requirement of “Site Inspection Standard for Civil Construction (Heating for Residence)” (DBJ/T01-44-2000). The authorities may use the detector to supervise the quality of energy-saving buildings in a fast, convenient and precise way.
6.2 Permeable Road Surface
At present, most of the urban road surface is impermeable. It is difficult for impermeable road surface to exchange the heat and water, and adjust the temperature and humidity of the road surface, which generates “heat island”. Moreover, it is likely to be waterlogged, and affects the comfort and safety. When there is concentrated rainfall, the rain can only be drained by the urban drainage system. While the permeable road surface may collect the rain water, thus save the water and protect the environment.

The complete technology of the permeable road surface developed by CSCEC includes the new road surface material and the construction methodology. By the optimization of the design, the rain may be collected and drained, which helps to reuse the rain. The application of this technology will help to improve the ecological environment and push the reuse of the rain.
 

It has been a government policy to promote the development of green building technology highlighted with saving land, saving energy, saving water, saving materials and protecting environment. To improve the development work of green buildings, CSCEC, in addition to the existing technology it has possessed, shall intensify the effort in technological renovation, uphold and take the lead in the development of green building. CSCEC will implement the government’s policy of technological renovation, develop further in the field of green building technology, continue the effort in innovation, to make new contributions in the development of green building technology.