Design And Application Of Recycled Aggregate Concrete Revetment Block

In order to meet both the needs of sustainable development strategy and practical construction,also to alleviate the adverse impact of construction waste on the ecological environment,applying recycled aggregate concrete,served as new green material,into structural engineering has become a research hotspot for the industry development.At the same time,various types of hydraulic masonry projects are turning the orientation from solely unction-based to fitting both the functional and ecological one.As an important defense line of embankment management,traditional masonry slope protection has been widely replaced by concrete block slope protection,which process favourable performance of both the engineering applicability and environmental friendliness.In a sequel,the revetment block made of recycled aggregate concrete emerges as the times require.While,there are also needs for further study about the material characteristics,mechanical properties and structure design issues.In this paper,the recycled aggregate derived from demolition waste of Anjia Cement Plant in Jinan City was chosen as the material,the basic mechanical properties and durability of recycled aggregate concrete have been studied with 13 mix ratios tests in laboratory.Based on this,the effects of types and content for recycled aggregate types against strength,freeze-thaw resistance and carbonization resistance were discussed,and then the optimum mix ratio of recycled aggregate concrete was determined applicable in practical engineering.Meantime,aiming at the design issues of new type of revetment block,the structure and mechanical properties of recycled aggregate concrete revetment block were studied by means of theoretical calculation and numerical analysis.All the work is to provide basis for further research on the design of revetment structure for recycled aggregate concrete with controllable performance and standardized parameters.The specific work carried out in this paper is as follows:(1)Through laboratory tests,the effects of recycled aggregate type,replacement rate and curing age on concrete strength were revealed,and the variation law of concrete strength with recycled aggregate proportion and age was obtained.The advantages and disadvantages of the single-doped coarse aggregate,fine aggregate and double-doped recycled aggregate concrete were discussed in term of the strength of concrete.(2)Aiming at the durability of recycled aggregate concrete,three groups of optimum types of concrete were tested,and the mechanism of surface damage,mass loss,relative dynamic modulus of elasticity and carbon dioxide erosion on recycled aggregate concrete under freeze-thaw cycle was explored.The recycled coarse and fine aggregate concrete was evaluated in the term of durability.(3)A new type of slope protection block with recycled aggregate concrete was designed by implementing theoretical analysis.The planar interlocking structure makes the new block more adaptable to the foundation deformation and has excellent overall performance synchronously.The 5%opening design of the block surface weakens the negative effect of the wave-induced buoyancy on the stability of the slope protection system.Moreover,the overall anti-slip stability of the revetment surface layer was verified by practical engineering.(4)Based on the dangerous sections slope protection project in the lower reaches of the Yellow River,the basic hydraulic and rock parameter were obtained,and the stress and displacement fields of the new recycled aggregate concrete revetment system under the effect of ice cover were calculated by using the finite element software ABAQUS.The overall stability and strength of the revetment system under the influence of ice cover were verified.By means of scheme comparison,the layout and combination of block with highest safety degree in engineering application was eventually determined.Relevant design methods provide a basis for the design of dangerous slope protection with recycled aggregate concrete.