微表处沥青混凝土抗磨耗性能影响因素

通过湿轮磨耗试验,对矿料级配、水泥含量及改性乳化沥青含量这3种微表处沥青混凝土抗磨耗性能的影响因素进行分析。试验结果表明:在级配范围内,矿料级配对微表处抗磨耗性能影响较小;湿轮磨耗值随着水泥含量和改性乳化沥青含量的增加而逐渐减小,并呈二次多项式分布,微表处抗磨耗性能相应增强;过多的水泥含量和改性乳化沥青含量并不能改善微表处混合料的抗磨耗性能,应通过试验确定水泥含量和改性乳化沥青含量。     

MS-3型微表处在高速公路预防性养护中的应用

以广东西部沿海高速公路为依托,对MS-3型微表处在该工程中的配合比设计作了介绍,阐明了微表处施工的工艺流程、技术要点及现场补给工艺,并对微表处后的路面性能进行了检测,指出该路面的抗滑性与封水性均达到了预防性养护要求。     

纤维对改良微表处混合料性能的试验

路用纤维作为微表处混合料的添加剂,目前国内还没有得到大面积推广应用。通过对比分析纤维微表处和普通微表处的水稳定性、抗磨耗性、抗车辙、马歇尔稳定度性能,全面评价了纤维微表处的优良路用性能,并简单分析了纤维改善微表处路用性能的简单机理。最后,通过试验路的应用情况,表明添加纤维后微表处具有优良的路用性能。     

聚酯纤维-橡胶颗粒微表处混合料路用性能与降噪特性

通过常规拌合试验、粘聚力试验、负荷轮车辙试验,优化聚酯纤维和橡胶颗粒的掺量,进而采用低温SCB试验、剪切疲劳试验研究纤维橡胶微表处混合料的低温性能与耐久性,并选取轮胎振动衰减与室内轨道下滑试验,研究评价纤维橡胶颗粒微表处混合料的减振与降噪特性。结果表明,掺加橡胶颗粒能延长微表处混合料的拌合时间,但橡胶颗粒对微表处混合料的抗磨耗性能、低温抗裂性和抗车辙性能有负面影响;掺加0.2%聚酯纤维后,微表处混合料的路用性能与抗疲劳性能明显改善;聚酯纤维-橡胶颗粒微表处混合料比普通微表处混合料有更好的路用性能和减振、降低路面噪声的性能。     

微表处湿轮磨耗值影响因素的探究

本文通过湿轮磨耗实验,研究了微表处混合料在水浸泡条件下的抗磨耗性能,总结出沥青酸值和粉料掺加量两个显著的影响因素。简而言之,在低于某酸值条件下,即使增大沥青混合料的油石比,微表处混合料的耐磨耗性能仍然不能满足规范要求。此外,0.075mm粒径以下的矿粉掺量,也是微表混合料抗磨耗能力的另一重要影响因素。     

微表处混合料性能及其应用

分析了微表处混合料配合比设计参数对混合料性能的影响,并通过湿轮磨耗试验和负荷车轮粘附砂试验对微表处混合料的性能指标进行了阐述,并论述了其在工程应用中应注意的问题,以推广微表处混合料的应用。     

聚合物改性乳化沥青微表处研究进展

为进一步提升沥青路面微表处使用品质,系统调查了国内聚合物改性乳化沥青微表处研究与应用现状,分析了聚合物改性乳化沥青微表处原材料类型及特点,对比评价了不同类型聚合物改性乳化沥青微表处性能。结果表明,聚合物改性乳化沥青微表处可拌和时间均能满足规范要求,且耐磨耗性能表现良好,其中树脂类表现突出,均值仅为231 g/m~2;相比树脂类及其他类型改性乳化沥青微表处,SBR,SBS改性乳化沥青微表处抗车辙性能明显提升,达34.78%～45.4%;此外,四种聚合物改性乳化沥青微表处水稳性能表现相当,30 min和60 min粘聚力均满足规范要求。     

掺加RAP的微表处混合料性能研究

为了多元化高效利用废旧沥青路面材料,并验证大掺量再生料(RAP)用于微表处混合料的可行性,试验研究了RAP掺量、乳化沥青用量等对再生料微表处混合料施工性能和路用性能的影响。结果表明,随RAP掺量增大,微表处混合料的施工和易性提高、粘附砂量增大,开放交通时间延长,但RAP掺量超过50%后,再生料微表处混合料粘聚力不符合JTG/T F40-02—2005《微表处和稀浆封层技术指南》要求。再生料微表处混合料的耐磨耗性能、抗车辙性能、水稳定性和低温抗裂性能随RAP掺量的增加而降低,因此用于填充车辙时,建议RAP掺量不宜大于40%。     

桥面微表处施工技术在银川绕城高速公路的应用研究

通过试验研究，确定了适合宁夏地区地材特点的微表处原材料；对乳化沥青的配伍性进行了反复的试验分析，确定了基质沥青和乳化沥青生产技术参数；进行了MS—II型和MS—III型混合料的配合比设计；对桥面水泥混凝土上铺筑微表处进行了详细的施工工艺设计和总结，为在宁夏干旱炎热地区进行桥面预防性微表处养护取得了经验；通车后对路用性能...     

沥青路面微表处养护措施长期路用性能研究

通过对广东省七条高速公路近年来微表处实施路段各路用性能指标(PCI,RQI,RDI,SRI)的对比分析,研究各路段微表处措施实施后的长期路用性能,并对其三种常见的病害类型:纵向裂缝、横向裂缝和坑槽的累计增长趋势进行统计分析,结果表明实施微表后的各路段具有良好的抗滑性能和封水性能,可以有效的恢复和改善路面的坑槽、裂缝等各种病害。     

The effect of mineralogy, texture and mechanical properties of anti-skid and asphalt aggregates on urban dust

In northern latitudes mineral dust is formed when cars use studded tyres and roads are sanded to obtain more traction on the icy surfaces. Anti-skid and asphalt aggregates with different textural, mineralogical and mechanical properties were tested with an indoor road simulator fitted with studded and friction tyres. The particle size distribution and proportions of dust from pavement and anti-skid aggregate were analyzed using SEM-EDX. The wear on the road pavement depends on the properties of the anti-skid and asphalt aggregate (particle size distribution, mechanical/physical and textural properties). Anti-skid aggregates, which contain mainly hard minerals (e.g. feldspars and quartz) and which have a low resistance to fragmentation, should be used with caution as they may break more easily into smaller particles and are likely to wear the pavement. By using high-quality anti-skid aggregates it is possible to reduce the amount of urban dust.     

预拌耐冲磨透水混凝土及其性能研究

研究了不同强度等级预拌耐冲磨透水混凝土的性能,探讨了预拌透水混凝土增强剂、β-活性氧化铝及抗冲磨材料对预拌耐冲磨透水混凝土的力学性能、收缩性能及耐磨性能的影响。结果表明:同一粒径下不同强度等级的预拌耐冲磨透水混凝土,加入增强剂能够有效改善其工作性能,降低收缩;加入β-活性氧化铝能够促进水泥中的物质与其极速反应生成钙矾石,同时降低氢氧化钙的含量,加快C3S的水化,从而进一步提高透水混凝土的强度;加入抗冲磨材料可减少其硬化后在透水渗水过程中的质量损失,提高透水混凝土的抗冲击耐磨损性能;β-活性氧化铝协同抗冲磨材料和预拌透水混凝土增强剂对透水混凝土的力学性能和耐磨性能的改善效果更佳。     

锰合金渣粗集料对路面混凝土性能的影响

将块状锰合金渣破碎成颗粒后制备为连续级配的锰合金渣粗集料,并以25%、50%、75%和100%的取代率取代天然粗集料以研究其对路面混凝工作性能、力学性能和耐磨性能的影响。结果表明:锰合金渣粗集料的针片状颗粒含量和吸水率大于天然粗集料,但按照适当比例级配后适用于各类路面混凝土;路面混凝土的坍落度随着锰合金渣粗集料取代率的增大而有较大幅度的减小;锰合金渣粗集料取代率小于50%时对路面混凝土的力学性能和耐磨性能影响不大,取代率超过50%以后路面混凝土的力学性能和耐磨性能相对于基准组分别提高了约10%和30%,利用锰合金渣粗集料可制备性能优良的路面混凝土。     

Effect of cutting tool blunting on the performances of various mechanical excavators used in low- and medium-strength rocks

Full-scale laboratory cutting tests that measure the specific energy (SE) are widely used to evaluate rock cuttability by mechanical excavators, and in particular roadheaders fitted with radial or drag-type bits. Radial or drag-type bits are often changed during operation as they wear and become blunt. In this study, full-scale cutting tests were carried out on different rock types using bits with varying degrees of wear in order to assess the impacts of pick bluntness on cutting forces and the SE. The relationships between wear flats and cutting forces, SE, and various rock properties such as uniaxial compressive strength, tensile strength, indentation index, Shore hardness, Schmidt hammer hardness, and density were examined and are discussed in this paper. The mean cutting force increased 2- to 3-fold and the cutting SE rose 4- to 5-fold with a 4-mm wear flat as compared to a sharp pick. Critical wear flats were plotted for different rock property values, and 25 MJ/m³ was considered the threshold SE above which cutting performance was considered to be poor. Best-fit predictive models based on statistical analysis of the laboratory cutting test results are introduced as a means to estimate SE as a function of bit type, wear condition, and various mechanical properties of the rock. These models can be used to predict the performances of mechanical excavators that use radial tools, especially roadheaders, continuous miners, and longwall drum shearers.     

二硫化钨改性聚四氟乙烯摩擦摆支座摩擦磨耗性能研究

针对摩擦摆隔震支座聚四氟乙烯PTFE摩擦滑移材料存在磨损率高、冷流性和熔体黏度高等问题,在PTFE材料中添加不同掺量的二硫化钨(WS2)。在对摩擦滑移材料基本物理力学性能进行试验研究的基础上,研究支座的摩擦磨损性能,并分析加载速度、压应力与摩擦系数的关系,进而综合给出PTFE材料中WS2含量的建议值,同时利用ABAQUS软件对摩擦副支座进行有限元分析和试验验证。结果表明：添加纳米级2%、4%WS2对PTFE进行改性,能在确保基本物理力学性能的前提下,显著改善PTFE的耐磨损性能,且摩擦系数与纯PTFE相差不大,是改进桥梁用摩擦摆支座性能的一种较好方法。     

Effect of wood dust type on mechanical properties,wear behavior,biodegradability, and resistance to natural weathering of wood-plastic composites

The present work reports the inclusion of different proportions of Mango/Sheesham/Mahogany/Babool dust to polypropylene for improving mechanical, wear behavior and biodegradability of wood-plastic composite (WPC). The wood dust (10%, 15%, 20% by weight) was mixed with polypropylene granules and WPCs were prepared using an injection molding technique. The mechanical, wear, and morphological characterizations of fabricated WPCs were carried out using standard ASTM methods, pin on disk apparatus, and scanning electron microscopy (SEM), respectively. Further, the biodegradability and resistance to natural weathering of WPCs were evaluated following ASTM D5338-11 and ASTM D1435-99, respectively. The WPCs consisting of Babool and Sheesham dust were having superior mechanical properties whereas the WPCs consisting of Mango and Mahogany were more wear resistant. It was found that increasing wood powder proportion results in higher Young’s modulus, lesser wear rate, and decreased stress at break. The WPCs made of Sheesham dust were least biodegradable. It was noticed that the biodegradability corresponds with resistance to natural weathering; more biodegradable WPCs were having the lesser resistance to natural weathering.     

工程机械用高强韧性耐磨铸钢

新研制的高强韧性耐磨铸钢,通过合理的热处理,可以得到优良的力学性能,既可满足斗齿的耐磨性要求,又能保证斗齿的安全使用。     

钒加稀土孕育对ZG20Crl钢强韧性的影响

本文通过试验证明加入钒及稀土后的ZG20Crl钢在力学性能、小能量多冲弯曲抗力、断裂韧性、耐磨性及凿岩机钎卡件的矿山使用等方面均优于原钢种，并对强韧化机理进行了探讨。     

玄武岩纤维对RPC电通量和力学性能影响

活性粉末混凝土（RPC）是一种高耐久性混凝土材料,具有很好的抗渗能力.研究通过对相同配合比的RPC掺入不同类型和不同掺量的玄武岩纤维进行力学性能试验和抗氯离子渗透试验.试验表明,当掺量为3kg/m^3时,玄武岩纤维对试件的力学性能提升较大;长度为6mm的玄武岩纤维,当掺量为5kg/m^3时,对应的试件抗氯离子渗透性能最大;长度为12mm的玄武岩纤维,当掺量为4kg/m^3时,对应的试件抗氯离子渗透性能最大.     

机场道面自密实钢纤维混凝土性能试验

将自密实混凝土技术与钢纤维混凝土技术结合起来,研究了白密实钢纤维混凝土配合比方法、施工工艺、力学性能、耐磨耗性能、抗渗性能和抗裂性能等.实践表明:自密实钢纤维混凝土不仅保证了施工质量、提高性能、而且综合效益好.