再生骨料混凝土不同龄期的力学性能

Mechanical Properties of Recycled Aggregate Concrete in Different Age

将废旧混凝土试块破碎加工成再生粗骨料，按照与天然粗骨料颗粒级配相一致的原则重新配制，然后以0％（质量分数，下同），50％和100％这3种粗骨料取代率、相同配合比配制再生骨料混凝土（RAC），测试其不同龄期的力学性能．结果表明：随着粗骨料取代率的增加，相同养护龄期的RAC立方体抗压强度、轴心抗压强度以及弹性模量均有不同程度降低；RAC的7d抗压强度增长较快，360d抗压强度较28d的提高34,4％～47．8％；28d轴心抗压强度与相同龄期的卓方体抗压强度呈线性关系；弹性模量随养护Ⅵ间的延长有所提高，与天然骨料混凝土（NAC）相比，RAC的360d弹性模量降低13．9％～24．2％．

Waste concrete cubes were broken into recycled aggregate, the gradation of which was in accord ance with corresponding natural aggregate, and then recycled aggregate concrete（RAC） with three replace ment rates of coarse aggregate of 0%, 50% and 100% （by mass） were mixed according to the same mix proportion. The mechanical properties of the RAC were tested in different periods. The test results show that with the replacement rate growing, the cube compressive strength, axial compressive strength and e lastic modulus of RAC in the same curing age all decrease in different degrees. The cube compressive strength of RAC cured 7 days increases rapidly. Compared with 28-day compressive strength, the 360-day compressive strength increases 34.4%to 47.8% The 28-day axial compressive strength of recycled aggre- gate concrete is linear with its cube compressive strength. As curing time increase, the elastic modulus of recycled aggregate concrete improves. The 360-day elastic modulus of RAC can be 13.9%to 24.2% lower than that of natural aggregate concrete（NAC）.