PROPERTIES OF CONCRETE SLUDGE AND ITS ADAPTABILITY AS FINE MATERIAL IN ASPHALT CONCRETE

摘要

A great quantity of concrete sludge hasoccured in ready mixed concrete plants and is currentlybeing disposed of as an industrial waste material at highcost. In addition, a great quantity of lime stone powderis needed for the production of asphalt concrete, whichexpends a lot of natural resources. For saving the naturalresources and reusing the waste material, it will bevaluable to replace natural resources by recycling waste material.The adaptability of concrete sludge as a fine material inasphalt concrete was investigated in the present study.Since the original concrete sludge taken from readymixed concrete plants has high moisture content, it mustfirst be dried and crushed. In the test, the concretesludge was dried in an oven and crushed by a LosAngeles machine. Then total 4 kinds of dried sludgepowder, belonging to two types of concrete sludge, wereprepared. The properties of dried sludge powder and itsadaptability as a fine material in asphalt concrete wereinvestigated. As the object of study, two types of asphaltconcrete were selected, and the Marshall stability, waterresistance, wear resistance and dynamic stability ofasphalt concrete were determined. Tests on asphaltconcrete without dried sludge powder were also executed as a control.Test results show that the dried sludge powder influencesthe properties of asphalt concrete. It is shown that thedynamic stability decreased due to the use of dried sludgepowder in all cases. However the properties of asphaltconcrete, such as Marshall stability, water resistance, wearresistance etc. were improved by mixing dried sludgepowder in some cases. Results also show that the influenceof dried sludge powder on asphalt concrete was low whenthe types of asphalt concrete, the types and content of driedsludge powder were suitable. As the conclussion, there is thepossibility that dried sludge powder can be used as a finematerial in asphalt concrete, especially in the case of sludge cake.