HIGH PERFORMANCE ADMIXTURES FOR SELF-COMPACTING CONCRETE : MECHANISM AND APPLICATION IN CHINA BUILDING
In this paper, the basic functional mechanism of high performance admixture (HPA) in SCC is discussed combining with the development of modern concrete admixture. Major applications of JM-SCC in China construction including hydraulic hydropower, transportation and industrial building, such as the Three Gorges Dam, the Gongboxia Hydropower Station, the Nanjing-Hangzhou Express Way, etc. are presented.
Self-compacting concrete. Development, present use and future
Self-compacting concrete was first developed in 1988 in order to achieve durable concrete structures. Since then, various investigations have been carried out and the concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making it a standard concrete. Recommendations and manuals for self-compacting concrete were also established.
Development of a Humidification¿Dehumidification System in a Quonset Greenhouse for Sustainable Crop Production in Arid Regions
This paper presents a pilot design for a humidification–dehumidification system in a Quonset greenhouse. The objective of this study was to investigate the potential of saline/brackish water evaporation and freshwater condensation to provide an alternative source of freshwater for irrigation in a greenhouse. Two humidifiers, each comprising a wall of evaporative cooling pads were used to increase water vapour inside the greenhouse as much as possible; and two dehumidifiers (i.e. condensers) condensed the water vapour. Preliminary testing of the performance of the greenhouse showed an increase in water vapour close to saturation after the second wall of cooling pads. The temperature of the water flowing in the dehumidifiers was always lower than the dew-point temperature of the air passing through them. Hence, condensation could occur and was observed on the dehumidifier. However, condensation was insufficient to result in a measurable quantity. Recommendations for design improvements of condenser are suggested.