Performance Tests And Analysis On Energy Saving Effect Of Structural Concrete Of Havdite Lightweight Aggregate

In recent years, with the development of higher floor, larger span and larger scale of modern construction engineering, the society put forward higher requirements for high-strength and lightweight aggregate concrete. Due to the advantages of lightweight, high-strength, good heat preservation and thermal insulation properties, good seismic performance and good comprehensive technical and economic effects, high performance lightweight aggregate concrete has become an important development direction of modern concrete. The good qualities of lightweight aggregate concrete owe to the special and porous structure of lightweight aggregate. Because of the limited natural lightweight aggregate, it is significant to research and develop synthetic lightweight aggregate. Currently, clay ceramsite is widely used. Clay is mostly taken from the arable land and it is not consistant with sustainable development strategies. The use of sludge ceramsite can not only avoid a secondary pollution problem but also agree with the principle of harmless, minimization and recycling of soild waste treatment. At present, a lot of research work has been done by domestic and foreign scholars focused on shale haydite,clay haydite, fly ash haydite, perlite and other lightweight aggregate concrete, while the study of sludge haydite concrete is relatively less due to starting rather late of sludge haydite research.In this paper, we prepared one kind of lightweight concrete of strength rating of LC35, density rating of1700or1800and the thermal conductivity of0.65～1.05W/(m· K) using shale and sludge haydite produced by Zhejiang Fangyuan Building Materials Technology Co., Ltd. The physical and mechanical properties, thermal properties and durability and other properties of haydite lightweight aggregate concrete with different sand rate and concrete admixtures were studied. The results indicate that the slump, the loss of slump, apparent density, compressive strength, elastic modulus, early-age contractions, long-time drying shrinkage and thermal conductivity will be influenced to some degree by sand rate of lightweight aggregate concrete. The slump and expansion degree of concrete decline with the increase of sand rate, while the loss of slump extends.Other properties of concrete increase with the increase of sand ratio. Reducing agent has negative effects on compressive strength of lightweight aggregate concrete, while it could markedly decrease the long-term drying shrinkage. The influence of expansive agent on compressive strength is relatively small. The shrinkage-compensating effect of expansive agent is related to its dosage. Air-entraining agents can reduce the compressive strength and decrease the long-term drying shrinkage under the appropriate dosage, while the cracking risk of concrete could increase in improper use.In addition, the building energy consumption of lightweight aggregate concrete for external loading-bearing structure was analyzed by DeST-h energy simulation software. The results show that the total energy consumption can be reduced by20%to30%and heat preservation and heat insulation effects are remarkable when the haydite lightweight aggregate concrete is used in bearing structure of self-insulation structural system.In conclusion, haydite lightweight aggregate concrete has better workability, physical and mechanical properties and durability. Particularly, it plays an important role to solve the enclosure structure energy-saving problem of high-rise building or larger thermal bridge structure because good thermal performance. Therefore, under the background of advocating energy conservation and environmental protection, haydite lightweight aggregate concrete has broad application prospects.