为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为...为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为变量,进行室内连续配筋混凝土-沥青混凝土(Continuously Reinforced Concrete Pavement-Asphalt Concrete,CRCP-AC)层间同步碎石封层(Synchronous Crushed Stone Seal Coat,SCSSC)抗剪模拟试验。结合三维有限元分析结果,确定了同步碎石封层最佳参数组合,提出了改善层间抗剪强度的建议。试验结果表明:集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力对同步碎石封层层间抗剪强度产生了显著影响;相较于4.75~9.5mm粒径的集料,为获取更高的抗剪切强度,在工程实践中宜选择9.5~13.2mm粒径的碎石作为同步碎石封层用撒布料;使用粒径为9.5~13.2mm的集料时,最佳参数组合为沥青洒布量1.6kg/m^(2)+碎石撒布量8kg/m^(2)。展开更多
Two types of stress relaxation tests were carried out to investigate the incubation time for incipient precipi-tation of Ti（C,N） in deformed austenite and （Ti,Mo）C in ferrite of ferritic Ti-Mo microalloyed steel T...Two types of stress relaxation tests were carried out to investigate the incubation time for incipient precipi-tation of Ti（C,N） in deformed austenite and （Ti,Mo）C in ferrite of ferritic Ti-Mo microalloyed steel The size dis-tribution, amount and chemical composition of precipitates were obtained by using physicochemical phase analysis, and calculated according to thermodynamics and kinetics. The experimental results demonstrated that the incubation time was reduced with increasing Ti content, and prolonged with the addition of Mo. After 30 % deformation at 850 ℃, the nucleation of strain-induced Ti（C,N） was a relatively slow process. On the other hand, the temperature where the nucleation rate of （Ti, Mo）C in ferrite was the highest descended first and then ascended with increasing Ti content, and so did the temperature where the incubation time was the shortest. The key point is that the tempera-ture of steel containing about 0.09 % Ti is the lowest. The mass fraction of MC-type particles with size smaller than 10 nm in steel containing 0.09% Ti and 0.2% Mo reached 73.7%. The size distributions of precipitates in steel containing 0.09% Ti were relatively concentrated compared with that in steel containing 0.07% Ti.展开更多
文摘为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为变量,进行室内连续配筋混凝土-沥青混凝土(Continuously Reinforced Concrete Pavement-Asphalt Concrete,CRCP-AC)层间同步碎石封层(Synchronous Crushed Stone Seal Coat,SCSSC)抗剪模拟试验。结合三维有限元分析结果,确定了同步碎石封层最佳参数组合,提出了改善层间抗剪强度的建议。试验结果表明:集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力对同步碎石封层层间抗剪强度产生了显著影响;相较于4.75~9.5mm粒径的集料,为获取更高的抗剪切强度,在工程实践中宜选择9.5~13.2mm粒径的碎石作为同步碎石封层用撒布料;使用粒径为9.5~13.2mm的集料时,最佳参数组合为沥青洒布量1.6kg/m^(2)+碎石撒布量8kg/m^(2)。
基金Item Sponsored by National Key Technology Research and Development Program in 11th Five-Year Plan of China (2006BE03A0)
文摘Two types of stress relaxation tests were carried out to investigate the incubation time for incipient precipi-tation of Ti（C,N） in deformed austenite and （Ti,Mo）C in ferrite of ferritic Ti-Mo microalloyed steel The size dis-tribution, amount and chemical composition of precipitates were obtained by using physicochemical phase analysis, and calculated according to thermodynamics and kinetics. The experimental results demonstrated that the incubation time was reduced with increasing Ti content, and prolonged with the addition of Mo. After 30 % deformation at 850 ℃, the nucleation of strain-induced Ti（C,N） was a relatively slow process. On the other hand, the temperature where the nucleation rate of （Ti, Mo）C in ferrite was the highest descended first and then ascended with increasing Ti content, and so did the temperature where the incubation time was the shortest. The key point is that the tempera-ture of steel containing about 0.09 % Ti is the lowest. The mass fraction of MC-type particles with size smaller than 10 nm in steel containing 0.09% Ti and 0.2% Mo reached 73.7%. The size distributions of precipitates in steel containing 0.09% Ti were relatively concentrated compared with that in steel containing 0.07% Ti.
