共查询到20条相似文献，搜索用时 531 毫秒
1.
毕永山 《河北能源职业技术学院学报》2006,6(3):58-60
集料是混合料结构形成的决定性成分,其岩性性质、物理力学指标以及外观形状的差异,对于混合料的工作性能产生很大的影响,集料级配的不同混合料的工作性能差异很大.文中就集料级配对沥青混合料的疲劳性能的影响进行了系统试验研究,得出了相应结论. 相似文献
2.
研究了4种粗集料针片状颗粒含量(0%,原状,30%,40%)对多孔沥青混合料骨架结构和性能的影响.分别采用二维数字图像处理、飞散试验、混合料破碎试验以及渗透试验,评价针片状对多孔沥青混合料的体积指标、骨架接触特性、耐久性、骨架稳定性和渗透性能的影响.试验结果表明:针片状含量对多孔沥青混合料的空隙率、骨架接触线长度、骨架接触点个数、集料破碎率和渗透系数具有显著的影响.由于粗集料针片状的破碎,多孔沥青混合料的有效空隙率、高温性能、长期耐久性以及骨架稳定性随着针片状含量的增大而衰减.与传统密级配沥青混合料相比,由于多孔沥青混合料具有开级配骨架,从而对针片状含量更加敏感,多孔沥青混合料应采用更严格的针片状含量要求. 相似文献
3.
《石家庄铁路职业技术学院学报》2016,(2)
通过一系列试验,对比玄武岩、石灰岩和天然砂三种细集料对矿料级配、沥青混合料高温稳定性和水稳定性的影响规律,同时分析了10%、16%和22%三种天然砂用量的沥青混合料的性能,最终提出针对不同等级公路的天然砂建议用量。 相似文献
4.
《东南大学学报》2017,(3)
为了研究关键因素对密级配沥青混凝土低温断裂性能的影响,采用离散单元法(DEM)和三维颗粒流程序PFC3D模拟弯曲断裂试验.基于随机生成算法和虚拟不规则粗集料库模拟集料级配和不规则形状、沥青砂浆以及空隙率的生成过程.然后,在虚拟试件中添加细观力学接触本构模型进行虚拟断裂试验,虚拟试验结果与室内试验结果对比验证了虚拟试验结果的有效性.此外,基于虚拟仿真采用正交试验研究集料和空隙的体积分数、集料和沥青砂浆的刚度、沥青砂浆内部粘结强度以及集料和空隙的分布对虚拟断裂试验的影响.研究表明,上述因素对断裂性能都有不同程度的影响,其中对弯拉强度和弯曲应变能密度影响最大的是沥青砂浆的粘结强度,对弯拉应变影响最大的是粗集料的体积分数.为了得到较好的密级配沥青混合料低温断裂性能,考虑沥青砂浆和集料的细观结构非常重要. 相似文献
5.
基于离散元方法的沥青混合料虚拟断裂试验(英文) 总被引：1，自引：0，他引：1
为了深入研究沥青混合料开裂特性, 设计了基于沥青混合料二维数字试件的断裂虚拟试验. 在考虑混合料二维截面的集料数量级配和集料不规则形状的基础上, 通过生成程序建立了沥青混合料的二维虚拟试件; 运用离散元方法, 建立了混合料二维离散元模型, 并进行了虚拟的中点弯曲小梁断裂试验; 为了验证虚拟试验方法的正确性, 在实验室内进行了沥青混合料小梁的中点弯曲断裂试验. 室内实体试验与虚拟试验结果的比较发现, 虚拟断裂试验获得的混合料断裂强度与室内试验结果一致, 表明虚拟断裂试验可以作为混合料断裂性能分析的辅助手段. 相似文献
6.
沥青混合料的抗裂性能在很大程度上决定了沥青路面的使用寿命,其粗集料骨架及细观介质成分（FAM）等内部结构组成的差异又会影响沥青混合料的抗裂性能。纤维因其优异的物理力学特性被广泛应用于提升沥青混合料的抗裂性能,为了有效表征纤维沥青混合料的瞬时损伤演化并评估其断裂特性,开发了一种新型测试方法,通过原位动态拉伸（ISDT）试验对沥青混合料细观损伤断裂性能进行表征。为了研究纤维沥青混合料细观损伤与宏观断裂性能之间的关系,设计添加和不添加纤维的沥青混合料,进行宏观半圆弯拉（SCB）及细观ISDT试验,定义荷载-位移曲线的特征参数表征其抗裂性能,并实时观测细观裂纹密度扩展情况。结果表明,随着纤维用量的增加,沥青混合料和FAM的断裂能和断裂韧性有相当的增加趋势,且沥青混合料及FAM的裂纹萌生及扩展存在滞后效应。因此,ISDT试验是评价纤维沥青混合料细观损伤断裂性能的一种有效手段。 相似文献
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沥青混合料作为一种感温性材料,其组成材料的导热系数关系到路面温度场的变化及路面性能.采用XIATECH TC3000型导热系数仪测试四种岩性集料、四种沥青和四种级配类型下的沥青混合料导热系数,并基于灰关联性和分形维数计算混合料组成特性和环境因素与导热系数的灰关联度.研究发现,水分、短期老化和温度环境因素对沥青混合料的导... 相似文献
9.
原材料质量控制分为进场质量检测和原材贮存质量管理两部分。沥青、集料、填料作为组成沥青混合料的原材料,是影响混合料质量的主要因素,因此只有控制好原材料质量,才能实现原材料到优质沥青混合料的良好转化。 相似文献
10.
运用有限元方法建立环氧沥青混合料细观结构模型,对其间接拉伸试验(IDT)进行数值模拟.首先借助图像处理技术得到由集料和沥青砂浆组成的环氧沥青混合料二相细观结构,并通过蠕变试验获取沥青砂浆常温下的黏弹性材料参数,最后结合有限元手段建立包含集料、砂浆等在内的混合料细观结构有限元模型.数值模拟结果表明,有限元计算的混合料劲度... 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
16.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
19.
Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
20.
Anton Franks 《English in Education》1999,33(2):39-49
This paper looks at the way drama works to bring a model of an arts curriculum into reality. He also shows how drama is valuable when discussed as a separate, autonomous subject in the school curriculum as opposed to one subsumed within English. He argues for a view of the arts and gives an example of a sequence of work in an English GCSE class based around Arthur Miller's play View from the Bridge. From this he draws out several strands about the relationship of the drama curriculum to the individual students and teachers, the school, and to culture. He also emphasises the primacy of performance in drama education. 相似文献