集料的颗粒物质特性与离析机理研究
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摘要
离析是造成沥青混凝土路面早期损坏的一个重要原因。国内外对于离析的研究主要集中在离析评价标准等方面,对材料产生离析的机理研究甚少。为更加有效地控制离析,有必要对离析的机理展开研究。像集料这样的由大量散体颗粒和空隙构成的颗粒物质体系有着许多独有的特性。本文以组成较为简单的集料为对象,从其颗粒物质特性角度去研究集料的运动特征及离析机理,为沥青混合料离析机理的研究探索一条新的路径。
本文首先阐述了颗粒物质领域的相关研究成果,论证了结合颗粒物质理论研究集料离析的可行性。然后根据混合料生产过程中的各环节分为三个方面来研究集料的离析，即集料成堆过程、料仓出料过程和运输振动过程。三个过程的离析现象研究均通过自行设计室内试验,分析试验结果,总结得到其离析机理。结果发现：集料成堆过程中,随着料堆倾角的增大,总体离析指数不断增大；当倾角达到休止角时,总体离析指数仍在增长,但各层离析指数趋于恒定。集料成堆过程中离析的主要机制是休止角离析。料仓出料过程中,对离析产生影响的有外部条件,也有集料本身特性。外部条件包括装料高度、料斗倾角及落料高度等,其中装料高度的影响最为重要；集料的粒径比、细料含量及平均粒径等属性也对料仓出料过程的离析有重要影响,粒径比越大,越容易发生严重的离析,细料含量越多,离析发生的几率越小,平均粒径的影响与料斗的出口尺寸有关,料斗出口尺寸与平均粒径的比例越大,离析程度越小。并提出渗透离析是料仓出料离析的主要机制。振动过程中的颗粒分离表现为随着振动时间推移,上中下各层中粗集料含量的偏差值逐渐趋于恒定,渗透机制对振动过程中颗粒的离析仍然起着重要作用。
Segregation is an important factor that causes the early damage of asphalt concrete pavement. Studies on segregation at home and abroad focus on its evaluation criteria or some other aspects, lacking of research on its mechanism. In order to control segregation more effectively, it is necessary to start research on the mechanism of it. The system like aggregates that consists of particles and voids is defined as granular matter, which has many special characteristics. In this paper, the movement characteristics and segregation mechanism of aggregates will be studied from the perspective of its granular characteristics, which is aimed at finding a viable method to study segregation of asphalt mixture. In this tentative research, the objects of the experiments are simple.
First of all, the relative research of granular matter is related and the feasibility to study aggregates segregation combined with the granular matter theory is demonstrated. Then, aggregates segregation is studied in the following three processes:heap forming, discharge from silo and undergoing vibration caused by transport. All the studies are carried with the following steps:experiment designing, data analysis and mechanism summary. The conclusions are as follows. In the heap forming process, as the angle of aggregates heap increases, both of the overall and layering segregation indexes grow. When the heap's angle equals to the angle of repose, the overall segregation index still increases while the layering segregation index tends to be a constant. The author believes that the angle of repose segregation is the main mechanism in the heap forming process. When aggregates discharge from silo, both of the external conditions and aggregate properties affect the segregation in this process. The external conditions include the loading height of aggregates, the angle of hopper and the discharge height. The most important factor among them is the loading height. The aggregate properties also have significant impact on segregation in this process, such as the particle size ratio, the fines content and the average particle size. The larger of particle size ratio, the more prone to severe segregation. The probability of segregation reduces with the increase of fines content. The influence of average particle size on segregation is related to the outlet size of hopper, as the ratio of outlet size of hopper and the average particle size increases, the segregation degree reduces. The author concludes that it is the infiltration segregation mechanism that works when aggregates discharge from silo. The study on segregation of aggregates under vibration is carried on a modified vibration compactor. The result shows that after a certain vibration time，the deviation of coarse aggregate content in each layer keeps on a constant value, and infiltration segregation mechanism still plays an important role in this process.
本文首先阐述了颗粒物质领域的相关研究成果,论证了结合颗粒物质理论研究集料离析的可行性。然后根据混合料生产过程中的各环节分为三个方面来研究集料的离析，即集料成堆过程、料仓出料过程和运输振动过程。三个过程的离析现象研究均通过自行设计室内试验,分析试验结果,总结得到其离析机理。结果发现：集料成堆过程中,随着料堆倾角的增大,总体离析指数不断增大；当倾角达到休止角时,总体离析指数仍在增长,但各层离析指数趋于恒定。集料成堆过程中离析的主要机制是休止角离析。料仓出料过程中,对离析产生影响的有外部条件,也有集料本身特性。外部条件包括装料高度、料斗倾角及落料高度等,其中装料高度的影响最为重要；集料的粒径比、细料含量及平均粒径等属性也对料仓出料过程的离析有重要影响,粒径比越大,越容易发生严重的离析,细料含量越多,离析发生的几率越小,平均粒径的影响与料斗的出口尺寸有关,料斗出口尺寸与平均粒径的比例越大,离析程度越小。并提出渗透离析是料仓出料离析的主要机制。振动过程中的颗粒分离表现为随着振动时间推移,上中下各层中粗集料含量的偏差值逐渐趋于恒定,渗透机制对振动过程中颗粒的离析仍然起着重要作用。
Segregation is an important factor that causes the early damage of asphalt concrete pavement. Studies on segregation at home and abroad focus on its evaluation criteria or some other aspects, lacking of research on its mechanism. In order to control segregation more effectively, it is necessary to start research on the mechanism of it. The system like aggregates that consists of particles and voids is defined as granular matter, which has many special characteristics. In this paper, the movement characteristics and segregation mechanism of aggregates will be studied from the perspective of its granular characteristics, which is aimed at finding a viable method to study segregation of asphalt mixture. In this tentative research, the objects of the experiments are simple.
First of all, the relative research of granular matter is related and the feasibility to study aggregates segregation combined with the granular matter theory is demonstrated. Then, aggregates segregation is studied in the following three processes:heap forming, discharge from silo and undergoing vibration caused by transport. All the studies are carried with the following steps:experiment designing, data analysis and mechanism summary. The conclusions are as follows. In the heap forming process, as the angle of aggregates heap increases, both of the overall and layering segregation indexes grow. When the heap's angle equals to the angle of repose, the overall segregation index still increases while the layering segregation index tends to be a constant. The author believes that the angle of repose segregation is the main mechanism in the heap forming process. When aggregates discharge from silo, both of the external conditions and aggregate properties affect the segregation in this process. The external conditions include the loading height of aggregates, the angle of hopper and the discharge height. The most important factor among them is the loading height. The aggregate properties also have significant impact on segregation in this process, such as the particle size ratio, the fines content and the average particle size. The larger of particle size ratio, the more prone to severe segregation. The probability of segregation reduces with the increase of fines content. The influence of average particle size on segregation is related to the outlet size of hopper, as the ratio of outlet size of hopper and the average particle size increases, the segregation degree reduces. The author concludes that it is the infiltration segregation mechanism that works when aggregates discharge from silo. The study on segregation of aggregates under vibration is carried on a modified vibration compactor. The result shows that after a certain vibration time，the deviation of coarse aggregate content in each layer keeps on a constant value, and infiltration segregation mechanism still plays an important role in this process.
引文
[1]沈金安. 关于沥青混合料的均匀性和离析问题[J]. 公路交通科技,2001,18(6)：20-24
[2]陆坤权, 刘寄星.颗粒物质[J].评述,2004,33(9)： 629-635,33(10)： 713-721
[3]雷宇.沥青混合料离析成因与控制方法研究[D].西安：长安大学,2007
[4]Cross S. A., Brown E. R. Effect of segregation on performance of hot mix asphalt[R]. Auburn:Highway Research Center, Auburn University,1992
[5]Stroup-Gardiner M., Brown E. R., et al. Segregation in Hot-Mix Asphalt Pavements (NCHRP Report 441) [R]. Washington D. C.:National Academy Press,2000
[6]Tashman L. E., Masad B. P., et al. Internal structure analysis of asphalt mixes to improve the simulation of superpave gyratory compaction to field conditions[J]. Journal of the AAPT,2001, Vole.70:605-645
[7]Hunter E., Airey G. D., Collop A. C. Aggregate Orientation and Segregation in Laboratory Compacted Asphalt Samples[J]. TRB, Washington D. C.: National Research Council,2004
[8]Wu J. X., Romero P. Analysis of Multivariate Models to Evaluate Segregation in Hot-Mix Asphalt Pavements[J]. TRB, Washington D. C.: National Research Council, 2004
[9]张学锋, 刘松, 张武矛等. 沥青混合料离析处理方法[J]. 交通科技,2001年第3期：23-25
[10]王端宜,李维杰,张肖宁.用数字图像技术评价和测量沥青路表面构造深度[J].华南理工大学学报(自然科学版),2004,32(2)：42-45
[11]王端宜, 张肖宁, 王绍怀. 表面离析作为沥青混凝土路面施工质量评价指标的研究[J]. 公路,2005年第1期： 54-58
[12]付辛,彭勇. 沥青混凝土路面离析评价方法新构想[J]. 公路,2005年第8期：343-346
[13]彭余华.沥青混合料离析特征判别与控制方法的研究[D].西安：长安大学,2006
[14]唐娴. 沥青混合料离析机理与评价指标[D]. 西安：长安大学,2008
[15]丁银萍.HMA级配离析特性的研究[D]. 大连：大连理工大学,2009
[16]沈金安、李福普、陈景.高速公路沥青路面早期损坏分析与防治对策[M].北京：人民交通出版社,2004：71-72
[17]陈克鸿, 黄宗远, 林文生. 级配变化对沥青混合料性质及路用性能的影响[J].筑路机械与施工机械化,2007年第1期：15-18
[18]李立寒, 麻旭荣.级配离析沥青混合料性能的试验研究[J].同济大学学报(自然科学版),2007,35(12)：1622-1626
[19]彭余华,沙爱民.沥青路面不均匀的影响因素分析[J].公路交通科技,2006,23(6)：9-13
[20]彭勇, 孙立军.沥青混合料路面离析原因研究[J].公路交通科技,2007,24(5)：67-70
[21]刘洪海,张建.沥青路面离析的材料和设备机理研究[J].武汉理工大学学报,2009,31(4)： 159-162
[22]郑晓光,朱云升,丛林.应用构造深度评价沥青混合料离析[J].公路,2005年第12期： 175-179
[23]王金辉, 林方雷.国外热拌沥青混合料离析评价方法简介[J].公路交通科技(应用技术版)
[24]陈少幸, 张肖宁.应用PQI评价沥青路面离析的研究[J].公路交通科技,2006,23(5)： 11-15
[25]麻旭荣,李立寒.沥青混合料级配离析判别指标的探讨[J].公路交通科技,2006,23(2)：48-51
[26]鲍德松,张训生.颗粒物质与颗粒流[J].浙江大学学报(理学版),2003,30(5)：514-516
[27]孙其诚, 王光谦. 颗粒物质力学导论[M].北京：科学出版社,2009：3-11
[28]孔维妹, 胡林, 吴宇等. 颗粒物质中的奇异现象. 大学物理,2006,25(11)：52-55
[29]史庆藩, 阎学群, 厚美瑛等. 振动混合颗粒形成的反巴西果分层及其相图的实验观测.科学通报,2003,48(4)：328-330
[30]姜泽辉,陆坤权,厚美瑛等. 振动颗粒混合物中的三明治式分离[J].物理学报,2003,52(9)： 2244-2248
[31]吴晶. 振动颗粒的分离与对流[D]. 哈尔滨： 哈尔滨工业大学,2007
[32]栗苏文,夏建新,曹斌.颗粒流动特殊现象探析[J].泥沙研究,2005,6：65-69
[33]Savage S. B., McKeown S., Shear stresses developed during rapid shear of dense concentrations of large spherical particles between concentric rotating cylinders[J]. J. Fluid Mech.,1983, Vol.127:453-472
[34]张长森. 粉体技术及设备[M]. 上海： 华东理工大学出版社,2007,250-250
[35]吴守一, 赵杰文. 农业散粒物料的偏析和脉动流化分选. 农业机械学报,1991年第3期： 29-35
[36]Ketterhagen W. R., Curtis J. S., Wassgren C. R., et al. Modeling granular segregation in flow from quasi-three-dimensional, wedge-shaped hoppers[J]. Powder Technology,2008:127-143
[37]邓学均. 路基路面工程[M]. 北京： 人民交通出版社,2005,315-317
[38]严载盛, 朱仁君.鳞状堆料混匀中和效果的测定[J].宝钢技术,1992年第6期：1-5
[39]谢敏王泽. 水运一次料场粉矿堆料方式的实践[J].武钢技术,2000,38(5)：36-43
[40]於海明,龚红菊, 韩英. 谷物休止角圆盘式快速测试仪的设计与试验[J].粮油加工与食品机械,2005年第12期：7-8
[41]余振,朱建新.漏斗形料仓下料倾角的确定[J].设计计算,2005年第4期：17-18
[2]陆坤权, 刘寄星.颗粒物质[J].评述,2004,33(9)： 629-635,33(10)： 713-721
[3]雷宇.沥青混合料离析成因与控制方法研究[D].西安：长安大学,2007
[4]Cross S. A., Brown E. R. Effect of segregation on performance of hot mix asphalt[R]. Auburn:Highway Research Center, Auburn University,1992
[5]Stroup-Gardiner M., Brown E. R., et al. Segregation in Hot-Mix Asphalt Pavements (NCHRP Report 441) [R]. Washington D. C.:National Academy Press,2000
[6]Tashman L. E., Masad B. P., et al. Internal structure analysis of asphalt mixes to improve the simulation of superpave gyratory compaction to field conditions[J]. Journal of the AAPT,2001, Vole.70:605-645
[7]Hunter E., Airey G. D., Collop A. C. Aggregate Orientation and Segregation in Laboratory Compacted Asphalt Samples[J]. TRB, Washington D. C.: National Research Council,2004
[8]Wu J. X., Romero P. Analysis of Multivariate Models to Evaluate Segregation in Hot-Mix Asphalt Pavements[J]. TRB, Washington D. C.: National Research Council, 2004
[9]张学锋, 刘松, 张武矛等. 沥青混合料离析处理方法[J]. 交通科技,2001年第3期：23-25
[10]王端宜,李维杰,张肖宁.用数字图像技术评价和测量沥青路表面构造深度[J].华南理工大学学报(自然科学版),2004,32(2)：42-45
[11]王端宜, 张肖宁, 王绍怀. 表面离析作为沥青混凝土路面施工质量评价指标的研究[J]. 公路,2005年第1期： 54-58
[12]付辛,彭勇. 沥青混凝土路面离析评价方法新构想[J]. 公路,2005年第8期：343-346
[13]彭余华.沥青混合料离析特征判别与控制方法的研究[D].西安：长安大学,2006
[14]唐娴. 沥青混合料离析机理与评价指标[D]. 西安：长安大学,2008
[15]丁银萍.HMA级配离析特性的研究[D]. 大连：大连理工大学,2009
[16]沈金安、李福普、陈景.高速公路沥青路面早期损坏分析与防治对策[M].北京：人民交通出版社,2004：71-72
[17]陈克鸿, 黄宗远, 林文生. 级配变化对沥青混合料性质及路用性能的影响[J].筑路机械与施工机械化,2007年第1期：15-18
[18]李立寒, 麻旭荣.级配离析沥青混合料性能的试验研究[J].同济大学学报(自然科学版),2007,35(12)：1622-1626
[19]彭余华,沙爱民.沥青路面不均匀的影响因素分析[J].公路交通科技,2006,23(6)：9-13
[20]彭勇, 孙立军.沥青混合料路面离析原因研究[J].公路交通科技,2007,24(5)：67-70
[21]刘洪海,张建.沥青路面离析的材料和设备机理研究[J].武汉理工大学学报,2009,31(4)： 159-162
[22]郑晓光,朱云升,丛林.应用构造深度评价沥青混合料离析[J].公路,2005年第12期： 175-179
[23]王金辉, 林方雷.国外热拌沥青混合料离析评价方法简介[J].公路交通科技(应用技术版)
[24]陈少幸, 张肖宁.应用PQI评价沥青路面离析的研究[J].公路交通科技,2006,23(5)： 11-15
[25]麻旭荣,李立寒.沥青混合料级配离析判别指标的探讨[J].公路交通科技,2006,23(2)：48-51
[26]鲍德松,张训生.颗粒物质与颗粒流[J].浙江大学学报(理学版),2003,30(5)：514-516
[27]孙其诚, 王光谦. 颗粒物质力学导论[M].北京：科学出版社,2009：3-11
[28]孔维妹, 胡林, 吴宇等. 颗粒物质中的奇异现象. 大学物理,2006,25(11)：52-55
[29]史庆藩, 阎学群, 厚美瑛等. 振动混合颗粒形成的反巴西果分层及其相图的实验观测.科学通报,2003,48(4)：328-330
[30]姜泽辉,陆坤权,厚美瑛等. 振动颗粒混合物中的三明治式分离[J].物理学报,2003,52(9)： 2244-2248
[31]吴晶. 振动颗粒的分离与对流[D]. 哈尔滨： 哈尔滨工业大学,2007
[32]栗苏文,夏建新,曹斌.颗粒流动特殊现象探析[J].泥沙研究,2005,6：65-69
[33]Savage S. B., McKeown S., Shear stresses developed during rapid shear of dense concentrations of large spherical particles between concentric rotating cylinders[J]. J. Fluid Mech.,1983, Vol.127:453-472
[34]张长森. 粉体技术及设备[M]. 上海： 华东理工大学出版社,2007,250-250
[35]吴守一, 赵杰文. 农业散粒物料的偏析和脉动流化分选. 农业机械学报,1991年第3期： 29-35
[36]Ketterhagen W. R., Curtis J. S., Wassgren C. R., et al. Modeling granular segregation in flow from quasi-three-dimensional, wedge-shaped hoppers[J]. Powder Technology,2008:127-143
[37]邓学均. 路基路面工程[M]. 北京： 人民交通出版社,2005,315-317
[38]严载盛, 朱仁君.鳞状堆料混匀中和效果的测定[J].宝钢技术,1992年第6期：1-5
[39]谢敏王泽. 水运一次料场粉矿堆料方式的实践[J].武钢技术,2000,38(5)：36-43
[40]於海明,龚红菊, 韩英. 谷物休止角圆盘式快速测试仪的设计与试验[J].粮油加工与食品机械,2005年第12期：7-8
[41]余振,朱建新.漏斗形料仓下料倾角的确定[J].设计计算,2005年第4期：17-18