摘要
水泥稳定碎石具有强度高、稳定性好、抗冲刷性能及抗行车疲劳性能较好的特点,但它在湿度变化(水分蒸发)时易产生干缩裂缝,导致沥青面层表面形成反射裂缝,进而影响路面的使用性能和使用寿命,这一缺陷是很明显的。且随着我国交通状况的变化,半刚性基层沥青路面遭遇到重载交通和早期损坏两大挑战,因此,提出能适应重载交通的长寿命优性能半刚性基层沥青混凝土路面设计方法,对目前重载交通高速公路的半刚性路面工程建设和养护将具有重大的经济效益和社会意义,同时对低等级公路沥青路面、城市道路沥青路面和机场跑道沥青路面的建设与养护也具有指导和参考价值。为此,本文分以下几个步骤进行了研究:
首先,定出所要研究的级配以及水泥用量,然后通过对掺加不同掺量膨胀剂、减缩剂的混合料进行击实试验结果,得出各掺量混合料的最佳含水量和最大干密度。与此同时,对掺与不掺外加剂的混合料做延迟时间击实试验,把其对混合料的影响做一个综合分析,得出延迟时间对掺外加剂混合料的影响结论。
然后,通过对掺加不同掺量膨胀剂、减缩剂的水泥稳定碎石混合料进行抗压强度、劈裂强度、劈裂模量以及干缩试验,选取梁亚军推荐的干缩抗裂系数来评价其抗裂性能,再结合抗压强度对其进行综合比较,得出最佳膨胀剂和减缩剂掺量。
最后,以此最佳外加剂掺量混合料与未掺外加剂混合料的路用性能做出综合分析,得出掺外加剂能有效改善水泥稳定碎石收缩性能的结论。
Cement stabilized gravel has high strength, good stability, anti-erosion properties and better anti-fatigue property, but it is easy to produce desiccation cracks when humidity changes (caused by evaporation), resulting in reflection crack on the bituminous pavement surface, then influences performance and the service life of the pavement. This flaw is very obvious. And along with changes in traffic conditions, semi-rigid asphalt pavement encounters two big challenges heavy load transportation and the early damage. Therefore, it will have the significant economic efficiency and the social meaning to the present construction and the maintenance of the semi-rigid highway pavement surface to propose a long life semi-rigid asphalt concrete pavement design method which is adapt to the heavy-duty traffic. It will also have instruction and reference value to the low grade road bituminous pavement, the urban road bituminous pavement and the runway bituminous pavement's construction and the maintenance. Therefore, this article has conducted the research with following several steps:
Firstly, the study set out to determine the grade and cement consumption, and then get the best amount of moisture and maximum dry density according to the compaction test results of different mixtures with different contents of expansive agent and shrinkage reducing admixture. Meanwhile, makes a generalized analysis of the admixture impact to the mixture by performing the delay time compaction test and gets a conclusion about the impact of delay time to the mixture.
And then ,through the compressive strength, the cleavage strength, the cleavage module as well as the air shrinkage experiment on the cement stabilized mixture with different contents, appraises its crack resistance performance by selecting the shrinkage anti-crack coefficient recommended by Yajun Liang then gets the best contents of expansive agent and shrinkage reducing admixture by recombining with compressive strength.
Finally, makes a generalized analysis about pavement performances of mixture with best amount of admixture and mixture without admixture then gets a conclusion about the effects of improving shrinkage performance of cement stabilized mixture by adding admixture.
引文
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