Reactive Powder Enhance The Strength Properties Of Recycled Aggregate Concrete

Recycled concrete technology has been considered to be the main measures to developthe ecological of green concrete and achieve the goal of sustainable development of buildingresources. Now we do a lot of research on recycled concrete, but research on recycledaggregate and recycled concrete performance enhancement is few, while the recycledaggregate intensive and pretreatment, is an important way to improve the recycled aggregateand recycled concrete. In this paper, in order to better promote the development andapplication of recycled concrete, some strengthened experimental research has been done onrecycled aggregate and recycled concrete. The main contents are:Firstly, the method is used of chemical enhanced and reactive powder slurry to wraprecycled aggregate to achieve the goal of infilling recycled coarse aggregate micro-cracks andgaps in this paper. By preparation of different water-cement ratio active slurry wrappingrecycled aggregate, aggregate of different performance enhancement is obtained. And theproperties of different strengthened aggregates are tested included apparent density, bulkdensity, moisture content, water absorption and crushing index values. Compared withrecycled coarse aggregate, strengthened aggregate apparent density increased byapproximately0.65%, the bulk density increased by about10%, water absorption reduced byabout10%; crushing index value reduced by26.4%. The performance of strengthenedaggregate with active powder prepared water-cement ratio of0.2(hereinafter referred to asRP0.2strengthened aggregate) is optimized.Secondly, concrete block is prepared by using the different strengthened aggregate, andthen into the standard curing. Compression test is carried out for the age of3days,7days,14days,28days. We recorded test data and drew the figure of compression strength-curing age,compressive strength of the concrete block of RP0.2is the maximum. Combined with thebasic performance analysis of strengthened aggregate, active powder slurry optimalwater-cement ratio is0.2.Thirdly, according to the recycled aggregate, natural aggregates, strengthened aggregateon mutual combination, we have completed the concrete compressive strength test, splittingtensile test and bending test. Results show that: for the coarse aggregate as “strengthenedaggregate and recycled aggregate” combination, compressive strength of concrete alldecreases with the increases of strengthened aggregate quantity. As for the “strengthenedaggregate and nature aggregate” and “recycled aggregate and nature aggregate” combination,compressive strength of concrete all increases with the increases of strengthened aggregatequantity and of recycled aggregate quantity. For the coarse aggregate as "strengthened aggregate and recycled aggregate" and "strengthened aggregate and natural aggregate"combination, splitting tensile strength of concrete increases with the increases of strengthenedaggregate quantity. Flexural strength of concrete shows volatility and great dispersion.Finally, chemically strengthened method of recycled aggregate has improved theaggregate basic performance, it makes the surface of strengthened aggregate more rough anddecreases crushed index value, but it contributes little to the compressive strength of concrete,it makes grate impact on splitting tensile strength.