Study On The Properties And The Modification Of Recycled Concrete

With the rapid development of the building industry, the building waste produced in the architecture industry also increase rapidly, which influences the environment and is harm to the society. After waste concrete are crushed, removed impurities, classification, they can be used as recycled aggregates. The technology of using recycled aggregates to confect recycled concrete not only may resolve the environment pollution produced by the waste concrete, but also may save crude aggregates resource, and bring the prominent social benefit, economic benefit and environmental benefit. It is a sustainable development road that can save resources and energy, alleviate the earth environment load and support the ecosystem balance.This paper summarizes that recycled concrete brings the influence to the environment and its domestic and international research status and development, and puts forward developing the recycled concrete technology is the need of social sustainable development. The paper designs a set of technics flow of producing recycled aggregates and uses scrap concrete in Wuchang vehicle factory to manufacture some recycled aggregates, and researches the basic properties of recycled aggregates such as apparent density, absorption, crush index, compacted density, porosity, etc. and analyses the properties change of recycled aggregates after the respective surface treatment with the polymer and polysilicone waterproofing agents, and then obtains the result that their absorption decreases and their properties improves after recycled aggregates are surface treated.The paper designs some teams of different mix proportion concrete according to the different replacement of the recycled aggregates and fly ash, and researches their working properties and mechanical properties, and analyses influence factors of the working properties and the mechanical properties of the recycled concrete such as the replacement rate of recycled aggregates, thereplacement amount of fly ash, surface treatment of recycled aggregates, adding the high range water reducing agents and mineral admixture, etc.The paper researches the durability of recycled concrete as to the sulphate-corrosion resistance, the permeability resistance, the frost-resistance, etc. and analyzes some factors, as to the replacement of recycled aggregates, the replacement of fly ash, the surface treatment of recycled aggregates, adding high range water reducing agent and mineral admixture, bring the influence to the properties of recycled concrete, and analyzes the economic feasibility of the application of the recycled concrete. It offers the advantageous support for the application of recycled concrete.The paper researches less on the structures and the properties of the structures of recycled concrete, and it deserves further research. At the same time in order to extend the application of recycled concrete, some standards and criterions must be established for the construction of recycled concrete. It need the support of the governmental industry policy and the guarantee of national law and statute. The government must establish compulsory special statute for the treatment of building waste, to promote the quick development of recycled concrete, a sort of new-style green concrete, at our country.