Research On Application Of Recycled Cement Concrete Aggregate In Asphalt Pavement

Being in the peak of infrastructure construction, a large amount of waste concrete is generated everyyear in China. Meanwhile vast high-quality gravel is needed in the construction of asphalt pavement.Utilizing of waste concrete in asphalt pavement may not only solve the problem of natural aggregateshortage but also help deal with construction waste. This thesis studies of application of recycled cementconcrete aggregate in asphalt pavement. Aimed to provide theories for application of RCA in asphaltpavement, detailed research is made on respects of crushing and production process of RCA, intensificationand property evaluation of RCA, performance and parameters of both cement stabilized and asphalt treatedRCA.To provide foundation for determination of preprocessing size, a crushing model is established on thebasis of average particle size of waste concrete, a standard for crushing ratio is proposed as well. Theproperties of three types of RCA, generated by primary crushing, secondary crushing and tertiary crushingprocess, respectively, were contrasted so as to analysis which layer RCA can be successfully applied in.Based on composition property of waste concrete, categorized generating process of RCA is presented.The self-rolled recycled aggregate concrete was utilized and its micro-character and chemicalcomposition of RCA were researched through X-ray\SEM and FIRT. And the engineering properities ofRCA were tested. It is found that exist of voids and microfractures in RCA leads to its properties of highwater absorption and crushing value, low density and strength. Organic silicon resin, metatitanic resinacceptor and silane resin acceptor was adopted to intensify RCA, and the intensification effect of organicsilicon resin was the optimum on the basis of comprehensive pavement performance. After beingintensified by organic silicon resin, both crushing value and water absorption of RCA decreased, satisfyingthe requirement of each pavement layer of all-class roads.Cement Stabilized Recycled Concrete Aggregate (CSRCA) with different RCA content were designedand their properties, including unconfined compressive strength, compressive resilient modulus, splittingstrength, flexural strength and fatigue resistance, were respectively tested. Accordingly, growth models ofeach mechanical index, relation model of mechanical indices, and fatigue equation were established, andthe influence factors were analyzed at the same time. The strength criteria for controlling of fatiguecracking was put forward on the basis of pavement loading response and strength and fatigue characteristicof RCA. Parameters of structure design of CSRCA pavement were proposed.Asphalt Treated Recycled Concrete Aggregate (ATRCA) with different RCA content were designedand performances including Marshall indices, high temperature stability, low temperature crackingresistance, water stability and fatigue resistance were tested. Theory of surface energy was used in the studyof adhesion between RCA and asphalt. Finally, parameters of structure design and criterion ofhigh-temperature of ATRCA pavement were proposed.The integrated design method of pavement and structure for CSRCA base or subbase and ATRCAbelow layer were proposed, respectively. And also design examples were described.