Research On Asphalt Pavement Cold In-Place Recycling Technique Using Cement As Additive

Though the highway construction is at the rush period presently in our country, some local roads and freeways should be maintained and reconstructed in succession. As a result, a mass of old pavement materials will be produced. These materials should be recycled instead of being discarded for fear of environment pollution. The old asphalt mixture is also one of them. Its recycling technique has been applied extensively in some developed countries and is just come into use in our country. This paper primary investigates the feasibility and technique of cement stabilized recycled asphalt mixture using in base and subbase course.The old asphalt mixture being dealt with cement is a cold in-place recycling method. The mechanism is that the crushed asphalt mixture and lime soil are reused and is stabilized by cement additive. So the material can be applied in base and subbase course such as cement stabilized aggregate.The physical and mechanical properties of the raw materials and the recycled mixture are studied respectively in this paper by means of indoor experiments. The primary mechanical indexes of the recycled mixture are tested, including the unconfined compressive strength, the resilient modulus and the cleavage strength. The changing laws of these indexes are related to the cement content, the ratio of old asphalt mixture to lime soil and the aged-period. And the relationship of each index is established. Furthermore, the water-resisting property, the frost resisting property, the dry shrinkage property, temperature contraction property and fatigue property are investigated. On the basis of the above-mentioned research, the effect of the raw materials towards the recycled mixture is analyzed. The design parameters and the fatigue test result given in this paper can be available in design, engineering as well in further research.The designing and constructing technics are also developed in this paper and the engineering performance of the recycled mixture used in highway entity pavement is comprehensively evaluated. The research indicates that cold in-place recycling of the old asphalt mixture is a favorable method for highway maintenance and reconstruction and especially should be applied in the region where is scarce of aggregate.