Effect of aggregate gradation on low temperature performance of asphalt paving mixtures

Low temperature cracking has become one of the important factors that diminish asphalt pavement’s ride quality and service life.Especially in cold region,cracking caused by low temperature is the main distress form.This paper discussed the effect of aggregate gradation on the low temperature performance in asphalt paving mixtures.A total of 11 asphalt mixtures with 11 different aggregate gradations and one asphalt binder content were studied.Volumetric properties of the coarse aggregate and asphalt mixtures showed aggregate grading has a significant impact on the degree of aggregate interlock in asphalt mixtures.A trend is existed in the low temperature performance with the change of gradation.With the aid of mathematic statistics,it indicates gradation affects the low temperature performance significantly.The findings also indicate the relationship between the degree of aggregate interlock in asphalt mixtures and the low temperature performance:With the stone-to-stone contact developed,the mixture has a high energy to resist contract and deformation at low temperature.The properties of fine aggregate and asphalt play an important part in resisting low temperature cracking in floating structure.But it provides lower energy to resist low temperature cracking compared to the skeleton structure.     

城市高架桥梁面层沥青混合料的选用

从城市高架自身特点及对桥梁沥青面层要求出发,对SMA、OGFC、AC粗级配(C型)类等常用桥梁沥青面层混合料的路用性能和施工工艺进行了综合比较。同时,结合工程实际,总结以往经验,分析各自适用条件,从而为实际工程应用提供指导、借鉴。     

节能环保理念在石家庄二环快速路提升工程中的体现

对既有路况较差、通行能力不足、景观效果较差的城市道路进行拓宽改造,是目前我国很多地区正在或即将面临的实际问题。以石家庄二环快速路提升工程为例,论述如何在道路红线受限、建设条件苛刻的条件下,引入新的设计理念,积极采用新材料、新技术、新工艺,体现低碳节能的环保理念,进而为类似工程建设提供借鉴。     

高粘性沥青应力吸收层防治反射裂缝研究

为提高半刚性基层沥青路面的防反射裂缝能力,采用高粘性沥青、改进的Superpave方法设计了富沥青、砂粒式的应力吸收层沥青混合料.试验研究表明,高粘性沥青应力吸收层混合料具有极好的低温变形、抗疲劳及弹性恢复能力,并具有较高的抗拉伸能力,能有效延缓沥青路面反射裂缝的发生,采用此材料铺筑的试验路和观测结果验证了室内试验的结论.     

城市枢纽型互通立交主线分合流设计

随着城市互通立交形态多元化的演变,传统的立交形式已经不足以适应一些特殊的路网节点。一个立交中出现多个主线流向,使得公路主线分合流设计在城市道路设计中也开始得到应用。结合中环线浦东段申江路立交设计,对主线分合流设计在城市互通立交设计中所涉及的几个主要问题进行简要的分析与探讨。