共查询到19条相似文献,搜索用时 109 毫秒
1.
现场碾压工艺是影响级配碎石层压实特性的重要因素。文章基于大量现场跟踪检测数据,研究了级配碎石层碾压过程中混合料空间结构组成、压实度、厚度随碾压遍数增加的变化规律。研究表明,合理的碾压次数能使级配碎石混合料形成"骨架-密实"空间结构体;级配碎石层压实度随碾压次数的增加呈"自然对数式"增长;级配碎石摊铺层越厚越易获得较高的压实度,宜取20 cm。 相似文献
2.
3.
4.
水泥稳定碎石基层的干缩特性是其最重要的路用性能之一,关系着路面的使用寿命.文章通过试验研究了集料级配、水泥剂量、含水量、压实度等因素对水泥稳定碎石基层干缩特性的影响,为其施工质量控制提供参考依据. 相似文献
5.
为了对比《公路沥青路面设计规范》(JTG D50-2006)中骨架密实级配(GF)和多级嵌挤骨架密实级配(MG)水泥稳定碎石之间的组成与性能差异,并深入研究MG级配水泥稳定碎石的性能,通过室内振动击实试验、力学强度试验和CBR颗粒流模拟技术对两种级配水泥稳定碎石组成结构及路用性能进行了对比研究,结果表明:与GF级配矿料相比,MG级配矿料的CBR值提高了8%~15%;与GF级配水泥稳定碎石相比,MG级配水泥稳定碎石最大干密度平均提高了1.4%,且易于压实,28d抗压强度提高了6%~12%、极限抗压强度提高了8%~20%,劈裂强度提高了8%~15%左右;实体工程应用结果表明,MG级配水泥稳定碎石有更好的抗裂性能。因此,MG级配水泥稳定碎石具有广阔的应用前景。 相似文献
6.
针对碎石基层的集料最大粒径,级配及混合料配合比计算、压实度质量控制4个方面问题进行了探讨,对现行公路基层施工枝术规范某些规定提出自己的见解,和同行们共同研究探讨。 相似文献
7.
8.
文章对AC-20三种矿料级配分别进行旋转压实试验和马氏击实试验,得到两种压实方式下三种矿料级配的沥青混合料体积指标,分析了两种压实方式下沥青混合料的空隙率随4.75 mm筛孔通过率、沥青油膜厚度的变化规律。研究结果表明:相对于马氏击实法,相同级配下旋转压实法得到的沥青混合料具有更大的毛体积密度,旋转压实法更有利于混合料的压实;旋转压实法下沥青混合料的空隙率与4.75 mm筛孔通过率、沥青油膜厚度具有高度相关性,相关系数分别达到1、0.923,对矿料级配具有更高的敏感性。 相似文献
9.
10.
11.
12.
文章针对我国常用的水泥稳定碎石和二灰稳定碎石两种半刚性材料,通过大量的室内试验研究,建立了两种材料动态模量与无侧限抗压强度和静态模量的关系,为没有条件进行动态模量试验的单位进行路面结构设计提供建议。 相似文献
13.
An extensive body of literature addresses the income elasticity of road traffic, in which income is typically treated as a homogenous quantity. Here we report evidence of heterogeneity in cross-sectional estimates of the elasticity of vehicle-kilometres of travel (VKT) with respect to income, when household income is disaggregated on the basis of income source.The results are generally intuitive, and show that the cross-sectional income elasticity of road traffic is not homogeneous as is typically specified in transport planning models. We show that in a number of circumstances the cross-sectional elasticity with respect to aggregate household income is of the opposite sign in comparison to more refined estimates of elasticity disaggregated by income source. If further research confirms that the elasticities we report here are causal in nature, neglecting the elemental effects could result in misleading results affecting practical infrastructure-investment and policy decisions, particularly as the mix of income sources shifts (e.g. if, as society ages, pension income increases as a share of all income).These results are of interest to both researchers and forecasters of travel demand, as well as designers of future travel survey instruments; the latter group must decide how to generate data about respondents’ income. Current expert guidance is to collect a single estimate of aggregate income at the household level. Future travel survey design choices will bound the analyses that can be supported by the resulting survey data, and therefore methodological research to re-visit the trade-offs associated with such choices is warranted. 相似文献
14.
15.
16.
文章通过PLAXIS有限元软件,分析了含硬壳层软土地基在荷载、硬壳层厚度、弹性模量、泊松比变化时的应力扩散特性,得出硬壳层的各种参数对应力分布的影响规律,为软土地基的应力分析提供参考. 相似文献
17.
文章通过抗渗、冻融、化学侵蚀试验及现场摩擦系数测试,研究了涂刷两种新型混凝土保护剂进行表面防水处理对机场混凝土道面耐久性的影响。结果表明:两种混凝土保护剂均能大幅改善混凝土的抗渗性能,降低混凝土冻融后的动弹性模量损失以及道面除冰液侵蚀下的强度损失,且不影响道面的抗滑性能。通过涂刷新型混凝土保护剂进行表面防水处理是提高混凝土道面耐久性的有效方法。 相似文献
18.
RELU-TRAN2, a spatial computable general equilibrium (CGE) model of the Chicago MSA is used to understand how gasoline use, car-VMT, on-the-road fuel intensity, trips and location patterns, housing, labor and product markets respond to a gas price increase. We find a long-run elasticity of gasoline demand (with congestion endogenous) of ?0.081, keeping constant car prices and the TFI (technological fuel intensity) of car types but allowing consumers to choose from car types. 43% of this long run elasticity is from switching to transit; 15% from trip, car-type and location choice; 38% from price, wage and rent equilibration, and 4% from building stock changes. 79% of the long run elasticity is from changes in car-VMT (the extensive margin) and 21% from savings in gasoline per mile (the intensive margin); with 83% of this intensive margin from changes in congestion and 17% from the substitution in favor of lower TFI. An exogenous trend-line improvement of the TFI of the car-types available for choice raises the long-run response to a percent increase in the gas price from ?0.081 to ?0.251. Thus, only 1/3 of the long-run response to the gas price stems from consumer choices and 2/3 from progress in fuel intensity. From 2000 to 2007, real gas prices rose 53.7%, the average car fuel intensity improved 2.7% and car prices fell 20%. The model predicts that from these changes alone, keeping constant population, income, etc. aggregate gasoline use in this period would have fallen by 5.2%. 相似文献