Laboratory Manufacture And Performance Investigation On Phosphate-based Rapid Patching Material Involved In Cold Recycling Of Asphalt Pavement

The technology of asphalt pavement cold recycling has attracted wide attention due to its distinguished environmental benefits,economic advantage and social returns.The purpose of this paper is to develop a new asphalt pavement patching material,named Cold Recycling Rapid Repairing Material(CRRRM),aimed to repair asphalt pavement diseases,primarily including rutting,cracks and potholes.The research of this paper mainly includes:(1)the basic properties of the waste asphalt mixture;(2)the main stabilizer of cold recycling process-magnesium phosphate cement(MPC);(3)CRRRM basic formula determined through the orthogonal test,and further optimization;(4)CRRRM's construction technology and pavement performance research.The basic formula experimental research results showed that intermediate aggregates could be maintained after crushing and screening of waste asphalt mixture.As expected,the aged asphalt was characterized by increased softening point whereas reduced penetration and ductility.In magnesium phosphate cement,the best mole ratio for borax and magnesium oxide is 0.2.In terms of CRRRM,the optimum water to MPC ratio is 0.35 whereas the optimal magnesium phosphate cement dosage,water glass dosage and fly ash dosage is 20%,5%and 5%,respectively.The experimental results of the optimizing CRRRM indicated that both rubber powder and water soluble polyurethane could improve CRRRM's appearance and toughness and the improvement of toughness by rubber powder was proved more significant.In addition,emulsified asphalt greatly affected CRRRM's mechanical property,water stability and low temperature performance.Both the water stability and cracking resistance at low temperature could positively be influenced by blending with certain amount of emulsified asphalt.