Experimental Study On The Recycled Fine Aggregate Concrete

Along with the continuous progress of human civilization, the concrete material per capital consumption is increasing. At the same time the environmental issue has become increasingly significant. Building garbage is the solid waste produced in the construction of buildings, maintenance, and the process of dismantling. The recycling of construction waste has become a common concern of all countries in the world issues, and also will lead to the recycling of construction waste in-depth study. This article is on the basis of the results of research of the accepting countrie"15"scientific and technological subjects (2004BA809B0305) in the country, and supported by the "11th Five-Year" plan focused on scientific and technological (2006BAJ02B0504) funding for completion.In this paper, particle shaping strengthen technology was used to strengthen the simple-crushing aggregates, and after screening we can get recycled fine aggregate. It made a comparative study on the recycled fine aggregate performance before and after the changes. The paper analyzed four factors that influenced the properties, mechanical properties, shrinkage performance and durability of the concrete. They include: the types of recycled fine aggregate (simple crushing fine aggregate and particle shaping fine aggregate), the replacement of recycled fine aggregate (0, 40%, 70% and 100%), fly-ash content ( 0 and 30%) and binding material content (300 kg/m~3, 400 kg/m~3 and 500 kg/m~3).The results showed that: Particle shaping can significantly improve the performance of recycled fine aggregate. The water consumption of the particle-shaping fine aggregate concrete is lower than the simple-crushing one, and its workability is much better. The Splitting tensile strength and compressive strength equals to the natural concrete and higher than the simple-crushing one. The shrinkage value is smaller than simple-crushing one, and the anti-carbonation performance, antifreeze properties, resistance to chloride ion permeability properties are all better than simple-crushing one.With the increase of fine aggregate replacement, the water consumption of the simple-crushing recycled fine aggregate concrete increases, the compressive strength and splitting tensile strength decreases, the antifreeze properties deteriorates; the water consumption of the particle shaping recycled fine aggregate concrete reduces, the splitting tensile strength and compressive strength increases, the anti-freeze performance does not change significantly. And with the increase of replacement, the contraction increases, anti-carbonation properties weakens and the resistance to chloride ion permeability increases of both of the two recycled fine aggregate concretes.When the Fly ash is added to 30%, the water consumption of the recycled fine aggregate concrete decreases slightly, the splitting tensile strength and compressive strength decreases, the anti-carbonation property decreases and the resistance to chloride ion permeability improved significantly, when 30% of fly ash is replaced, the permeability of the recycled aggregate concrete can evenly reduce 36.1%.With the increase in the amount of binding material, the water consumption of the fly ash concrete reduces while the concrete without fly ash reduces. The splitting tensile strength and compressive strength increases. The shrinkage value increases 5.2% with the additional binding materials for 100kg/m~3, Anti-carbonation and the antifreeze performance enhances, the resistance to chloride ion permeability increase 27.6%, with the additional binding materials for 100kg/m~3 .Particle-shaping recycled fine aggregate concrete has a good performance on the workability, mechanical properties, shrinkage performance, anti-carbonation performance and resistance to chloride ion permeability. It can be applied to the structure engineering.