【摘要】 将再生微粉以0、10%、20%、30%、40%的取代率取代水泥后制备的混凝土试块分别在标准养护7 d、14 d时进行冷冻形成10%、20%的初始损伤率，继续养护至28 d后进行冻融循环试验。通过质量损失率、动弹性模量、微观结构变化，并结合应力-应变模型进行曲线拟合等指标反映初始损伤和冻融循环的耦合作用对混凝土性能的影响规律。研究结果表明：初始损伤度增大会降低混凝土抗压强度和抗冻性，每增加10%的初始损伤，抗压强度下降8%～12%，冻融循环次数增加也导致混凝土抗压强度持续降低。0次冻融且无损伤时抗压强度最高，为38.45 MPa,100次冻融后仍保持33.46 MPa。在相同条件下，20%取代率的混凝土抗冻性最佳，结构较为完整且孔隙最少，40%取代率的混凝土抗冻性最差，结构较为松散且有害孔较多。更多还原

【Abstract】 The recycled micropowder was replaced with cement by 0,10%,20%,30% and 40% replacement rates,and the concrete test blocks prepared were frozen at 7 d and 14 d of standard curing,respectively,to form an initial damage rate of 10% and 20%.Continue to cure until 28 d before conducting freeze-thaw cycle experiments.The influence of the coupling effect of initial damage and freeze-thaw cycle on concrete performance is reflected by the mass loss rate,dynamic elastic modulus,microstructure change,and curve fitting combined with the stress-strain model.The results of the study show that the increase of initial damage reduces the compressive strength and frost resistance of concrete.For every 10% increase in initial damage,the compressive strength decreases from 8% to 12%.The increase in the number of freeze-thaw cycles also leads to a continuous decrease in the compressive strength of concrete.The compressive strength was the highest when there was 0 time freeze-thaw without damage,which was 38.45 MPa.After 100 times freeze-thaw,it still maintained33.46 MPa.Under the same conditions,the concrete with 20% substitution rate has the best frost resistance,the structure is relatively complete and the pores are the least.The concrete with a 40% replacement rate has the worst frost resistance,and the structure is loose and there are many harmful pores.更多还原