【作者】 张桂霞；

【导师】 胡力群；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2010， 硕士

【摘要】 骨架密实结构的水泥稳定碎石粗集料过多造成的离析会使水泥稳定碎石基层压实不足,造成路面早期病害严重。本文从掺加外加剂的角度,研究掺加外加剂(高效减水剂和粉煤灰)能否改善水泥稳定碎石基层的易密性。需要注意的是,在本文中,粉煤灰是作为外加剂使用的,而不是作为水泥的替代物。首先确定了水泥稳定碎石外加剂的掺加顺序,即为使外加剂的效果达到最好的发挥,应采用后掺法。针对不同外加剂掺量的水泥稳定碎石进行了振动击实试验,确定了单掺减水剂或粉煤灰、双掺减水剂和粉煤灰,最大干密度最大时,减水剂和粉煤灰的掺量。在已有的评价材料易密性方法的基础上提出了一种新的评价骨架密实型水泥稳定碎石易密性的指标—振动成型时间,并通过大量试验得出,当单掺CT高效减水剂时,掺量为1.0%时,振动成型时间最短；当单掺粉煤灰时,掺量为30%振动成型时间最短；当同时掺加CT高效减水剂和粉煤灰时,减水剂掺量为1.0%,粉煤灰掺量为20%时,振动成型时间最短。振动成型时间越短,说明材料越容易密实。针对几种最能改善水泥稳定碎石易密性的外加剂掺量,进行水泥稳定碎石路用性能试验,试验结果表明,最能改善骨架密实型水泥稳定碎石易密性的几种外加剂掺量,也可以起到改善水泥稳定碎石路用性能的效果,具体表现为单掺减水剂或者粉煤灰、双掺减水剂和粉煤灰,使得骨架密实型水泥稳定碎石的强度、刚度、疲劳寿命大幅度提高,干缩系数、温缩系数明显减少。同时,试验结果还表明,双掺减水剂和粉煤灰,二者的效果得到叠加,改善骨架密实型水泥稳定碎石易密性和路用性能的效果更好。因此,在骨架密实结构的水泥稳定碎石的施工过程中,使用掺加外加剂来改善其易密性的方法可以推广使用。更多还原

【Abstract】 Plenty of coarse aggregates consisting in cement stabilized macadam which belongs to framework dense structure leads to segregation phenomenon. Cement stabilized macadam base can not being compacted enough is result from this phenomenon, and then serious pavement distresses occur. In this text, the possibility of additives(fly ash and water reducing admixture) improving the compactability of cement stabilized macadam base is researched. Using way of fly ash need to be pay more attention to.Fly ash is used as additives,and is not used as alternatives. In this text,firstly, the adding order of alternatives is researched, and in order to achive the best effect, latter admixing method is used in this text. According to cement stabilized macadam which contains different admixture amounts, vibration hit-soliding experiments are done.As maximum dry density reaches the maximum, mixing amount of additives(fly ash and water reducing admixture) which can be uni added or double added is determined. Based on methods of assessing the compactability of materials,a new method is suggested, vibration formation time.In this text, according to a lot of experiments, main conclusions are achived:when water reducing agent dosage is 1.0%, vibration formation time is shorest; when fly ash dosage is 30%, vibration formation time is shorest; when fly ash dosage is 20% and water reducing agent dosage is 1.0%, vibration formation time is shorest. More shorter of vibration formation time,the more easy to be compacted. According to mixing amount of additives which have best effects in improving the compactability of cement stabilized macadam base belonging to framework dense structure, pavement performances are measured, and the results showed that the pavement performances of cement stabilized maca belongs dam to framework dense structure are also improved.The concrete manifestations are:when fly ash or water reducing admixture is added,or fly ash and water reducing admixture are added at the same time, strength、fatigue life and rigidity are improved,and shrinkage coefficient and temperature contraction coefficient decrease; When fly ash and water reducing admixture are added simultaneously, their effects in improving the compactability and pavement performance are more significantly. In the construction process of cement stabilized macadam which belongs to framework dense structure, adding additives to improve compactability can be extended.更多还原