不同改性剂改性沥青性能分析

通过常规试验和SH RP沥青试验,对国内外常用的几种不同改性剂改性沥青的性能进行了对比研究,同时结合相应改性沥青混合料的高温性能、低温性能和疲劳性能研究,比较了不同改性沥青的路用性能。     

广西道路沥青气候适用性分析

根据广西的地形、地貌及气候特点,结合收集的气象资料,在分析计算广西沥青路面高温、低温设计温度的基础上,采用美国Superpave和中国沥青气候分区方法,分析确定了适用于广西地区的道路沥青PG分级和气候分区。     

高掺量橡胶改性沥青性能研究及优选

橡胶沥青的掺量大小对沥青的性能和使用成本都有显著的影响。为了提高橡胶改性沥青掺量的同时兼顾其性能,本研究选择20%、30%、40%、50%4种掺量的橡胶改性沥青,通过温度扫描试验和弯曲梁流变试验评价不同掺量的橡胶改性沥青的高温性能与低温性能,并根据规范要求确定PG分级。通过拟合半对数坐标下车辙因子-温度曲线,对比了老化前后各个沥青的感温性。结果表明：高温流变性能方面,老化前后车辙因子大小均表现为40%RA>30%RA>50%RA>20%RA,当胶粉掺量超过40%以后,高温性能显著下降。随着胶粉掺量的提高,胶粉改性沥青的高温性能先上升后下降,考虑高温性能,则胶粉掺量不宜超过40%。从半对数坐标的拟合结果来看,掺量在20%～40%之间时,胶粉能提高沥青的温度稳定性。低温性能方面,随着胶粉掺量的提高,胶粉改性沥青的低温变形能力和应力松弛能力逐渐增强。综合温度扫描试验和BBR试验的结果,得到4种胶粉改性沥青的PG分级结果：20%RA为PG82-22,30%RA/40%RA为PG88-28,50%RA为PG82-34。综合考虑性能和经济性,在实际工程中较为推荐30%掺量和40%...     

SBS改性沥青常规指标与SHRP性能指标的关系

笔者选取了具有代表性的4种国产重交通道路石油沥青和4种专用型道路沥青改性剂,在试验室里采用高剪切的改性工艺制备得到16种SBS改性沥青;运用常规试验方法和SHRP试验方法,对制备得到的SBS改性沥青的高低温性能进行了研究;在综合分析各种沥青的试验结果的基础上,提出了常规高低温指标与SHRP高低温性能指标之间的关系.     

SHRP沥青性能分级量度的探讨

利用SHRP胶结料试验仪器,基于表征沥青路用性能的流变力学指标,测试了不同标号、不同老化程度的道路沥青在一定适用温度范围内的性能特征.分析结果表明,胶结料高温指标车辙因子G＊/sinδ对于不同标号沥青的响应程度较低温指标劲度模量S明显偏大.也即,6℃量度的SHRP温度分级在反应不同沥青使用高温与使用低温性状的差异时并不协调.进一步分析得出,与目前针入度级方法比较,在评定试验沥青低温性能的量度方面,SHRP方法的温度分级量度偏大.     

Utilizing naturalistic driving data for in-depth analysis of driver lane-keeping behavior in rain: Non-parametric MARS and parametric logistic regression modeling approaches

It is known that adverse weather conditions can affect driver performance due to reduction in visibility and slippery surface conditions. Lane keeping is one of the main factors that might be affected by weather conditions. Most of the previous studies on lane keeping have investigated driver lane-keeping performance from driver inattention perspective. In addition, the majority of previous lane-keeping studies have been conducted in controlled environments such as driving simulators. Therefore, there is a lack of studies that investigate driver lane-keeping ability considering adverse weather conditions in naturalistic settings. In this study, the relationship between weather conditions and driver lane-keeping performance was investigated using the SHRP2 naturalistic driving data for 141 drivers between 19 and 89 years of age. Moreover, a threshold was introduced to differentiate lane keeping and lane changing in naturalistic driving data. Two lane-keeping models were developed using the logistic regression and multivariate adaptive regression splines (MARS) to better understand factors affecting driver lane-keeping ability considering adverse weather conditions. The results revealed that heavy rain can significantly increase the standard deviation of lane position (SDLP), which is a very widely used method for analyzing lane-keeping ability. It was also found that traffic conditions, driver age and experience, and posted speed limits have significant effects on driver lane-keeping ability. An interesting finding of this study is that drivers have a better lane-keeping ability in roadways with higher posted speed limits. The results from this study might provide better insights into understanding the complex effect of adverse weather conditions on driver behavior.     

SBS改性沥青抗裂特性的SHRP试验研究

为了探求SBS改性沥青的抗疲劳性能和低温抗裂性能,以三种常用的国产沥青为基质沥青,SBS为改性剂,通过选择合适的工艺条件,制备得到成品SBS改性沥青.运用SHRP试验方法中的动态剪切流变仪(DSR)、弯曲梁流变仪(BBR)分别对三种SBS改性沥青的RTFO PAV残留物的流变特性进行了试验研究,结果表明:在较宽的温度域范围内,经RTFO PAV老化的SBS改性沥青试样的复数剪切模量G 、相位角δ、疲劳开裂因子G Sinδ、低温蠕变劲度S及蠕变速率m值与试验温度T之间存在着良好的相关性.     

SHRP沥青数据库蜡含量数据分析

通过分析SHRP(美国战略性公路研究计划)研究数据,表明路用性能与蜡含量之间没有令人信服的关系,路用性能更受到其他因素的影响,如沥青化学组成和流变性能等.     

Domix改性沥青及混合料的路用性能研究

介绍了外掺剂Domix的性能及其作用机理.应用SHRP试验方法对不同Domix掺量的沥青结合料进行了动态剪切试验、135℃粘度试验和小梁弯曲蠕变试验,并对加入Domix改性剂后的沥青混合料进行了车辙试验、弯曲破坏试验、疲劳试验和冻融劈裂试验,结果表明,加入Domix后,沥青混合料的各项路用性能都得到了较大程度的提高,尤其是高温稳定性得到了极大的提高.并对添加Domix和SBS改性剂的沥青混合料进行了经济分析,结果表明Domix具有较好的经济性.