Experimental Study On Mechanical Properties Of Pouring Asphalt Concrete

To explore and study on physical and mechanical properties of pouring asphalt concrete which is made up of the natural gravel as coarse and fine aggregates, combining Xinjiang actual construction, analysis and discuss on asphalt concrete stress-strain relationship, the reasonableness of relevant test method, the mixture of pouring asphalt concrete and some problems in the design and construction process natural sandy gravel, the Stress-strain relationship, rationality of test method and some questions in design and process of construction, by water stability test and triaxial test,. The results show that:(1) Through the mixture ratio test and pouring test about Core-Wall Dams of the pouring asphalt concrete which have been built or are being built,the results show that:asphalt content can be less than9.0%of the lower limit which is floor level of 《Design code of asphalt concrete facings and cores for embankment dams》,if high label asphalt (70(A),80(A) asphalt of Karamay) has used. If porosity of asphalt is small and density is high, viscosity and separating satisfy the standard requirement.(2) The pouring asphalt concrete could be forming by weight and be compaction because of the asphalt content is higher than roller compacted. When the temperature rises,the pouring asphalt concrete could occur large deformation easily. So, the test temperature and the test method of 《Test code for hydraulic bitumen concrete》 are not applicable of pouring asphalt concrete in Marshall test. It is more shitable for construction characteristics and physical properties of pouring asphalt to use static pressure method for specimens and test temperature take20℃(3) Through the water stability test on pouring asphalt concrete, the results show that the coefficient of water stability is almost same in different temperature, in all are greater than0.9of the specification.The test method of 《Test code for hydraulic bitumen concrete》 is not able to evaluate the effect of the water stability of pouring asphalt concrete during the short term.The test method which is suitable for pouring asphalt concrete still needs research and discussion.(4) Through the test of adhesion between natural sandy gravel and asphalt,the results show that:the Boiled time and the sodium carbonate solution concentration of 《Test code for hydraulic bitumen concrete》, can’t distinguish the adhesion between different lithology aggregate and asphalt. The adhesion can be distinguished by extending boiled time of coarse aggregate; the adhesion can be distinguished by improving solution concentration of fine aggregate. The adhesion effect should be better because of wrapped cement and limewater, the effect of limewater is better, with the increasing of concentration; the adhesion effect of fine aggregate should be better because of wrapped cement, the effect of limewater is better with the increasing of cement contents.(5) Through the triaxial tests on pouring asphalt concrete of different asphalt content and different temperature conditions, the results show that the hyperbolic segment range about the stress-strain curves of pouring asphalt concrete wide, the stress-strain curves of pouring asphalt concrete showing the stress hardening form, and with the increasing of asphalt content, temperature, and the phenomenon of stress hardening is more obvious, the hyperbolic segment range increased.The theoretical curve of Duncan-Chang model and modified Duncan-Chang model are consistent with the test curve.(6) Under lower confining pressure,it is very similar between the destruction deviator stress of two model; under higher confining pressure,with the increase of confining pressure, the destruction deviator stress of the modified Duncan-Chang model increase almost flat, growth rate reduce,the destruction deviator stress of the Duncan-Chang model increase almost linearly, its’ value is significantly greater than the destruction deviator stress of the modified Duncan-Chang model.