Researching And Developing Multifunctional Additives Of Cement Stabilized Macadam Base

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.