Research On Construction Waste Regenerated Autoclaved Aerated Concrete

With the accelerating process of China’s economic construction, the construction industry for a period of development is at full speed, which the resulting hundreds of millions of construction waste become a difficult problem in front of people associated with broken and constructed buildings. A large number of construction waste placed nowhere, some directly landfill and more directly deposited in the open air cultivating land, which cause environmental pollution. At present, the recycling of the construction waste has attracted many attentions of the society from all the country.From the quantity and quality of construction waste, what mainly for dealing with is recycling waste concrete. As a result, most of the research focuses on the application of recycled concrete aggregate whose recycling ways is so narrow and low efficiency,while for the waste concrete is applied to the new building wall materials’ research is less.This paper was mainly prepared for the research on using construction waste autoclaved aerated concrete. In order to achieve maximum utilization of waste concrete.Test firstly studied the properties of the waste concrete raw materials; Secondly studied waste concrete as a single siliceous raw material prepared for regeneration aerated concrete with comparison to fly ash aerated concrete, and did the research on dopping with different proportion of fly ash instead of waste concrete preparation recycling autoclaved aerated concrete products, so that obtain construction waste regeneration of aerated concrete’s formula; And then studied the water material ratio, dosage of lime, cement and aluminum powder of the four factors which effect on the properties of products in the process of preparing regenerated aerated concrete with the methed of single factor test, and studied on grinding waste concrete to different fineness, calcineing waste concrete with high temperature and adding chemical agents for these three techniques of waste concrete inspired; Finally, had basic analysis of the strength forming mechanism and benefit of construction waste regeneration to autoclaved aerated concrete.Through analysing the chemical composition and mechanical properties of the waste concrete, the test results show that the composition of waste concrete is with high content of Si O2, hydrated calcium silicate content is higher in XRD spectrum, waste water consumption standard consistency and setting time of concrete and stability all meet the standard requirements, the proportion of waste concrete with 40% mixed to cement mortar strength of 28 d has reached to 32.5 cement’s strength, all indicts that waste concrete itself is a certain activity.Waste concrete preparation for autoclaved aerated concrete mixture ratio test results show that using waste concrete as single siliceous raw materials prepared for product whose strength is too low, but in the case of fly ash and waste concrete mixed which successfully made products whose dry density is 624.19 kg/m3 and the compressive strength is 3.57 MPa. Single factor test results show that the influent factors of product is water material ratio, dosage of lime, cement, aluminium powder which has a best value respectively. When the value of water material ratio is 0.6, lime content 18%, cement 12%, aluminum powder 0.09%, their performance is up to an optimal value under the condition of products corresponding. When the waste concrete is grinded for 55 min, the inspired active will be best; Waste concrete calcined by high temperature what increased its activity to a certain extent,, and the activity of waste concrete is enhanced by the calcination temperature, 900 is best, ℃ and also the most strong products; After adding different proportions of Si O2 powder,products strength has a certain extent.Analysis of the strength forming mechanism and benefit of construction waste recycled autoclaved aerated concrete results show that the crystallization products’ SEM scan images contain more good flake cuny mullite, hydration products’ morphology is better. Manufacturing energy consumption of per unit volume renewable aerated concrete products save 0.39 kgce than common sintered clay brick, production cost is 98.29 yuan and equivalent to half of the market price. It has remarkable economic and social benefits.