| With the economic development in China, while the city construction develops so rapidly, the highway reconstruction is meeting new opportunities as well as new challenges. During the process of reconstruction of highways there exists such a method that the former seeded strip is cleaned and then is reinforced together with the new base course so as to widen the highway. With the reconstruction practice of the northern part of 205 State Highway within Binzhou city, the thesis introduces an economical and practical method of dealing with the former seeded strip as well as promoting the integral intensity of reinforced base course, which effectively avoids the longitudinal cracks and the structural destruction of the pavement due to the differential settlement.During the process of reconstruction of the northern part of 205 State Highway within Binzhou city, the following precedures have been adopted as: 1) between 20cm and 80cm beneath the former seeded strip, lime-soil stabilization has been selected due to the local geographical features and the shortage of inorganic matrix;meanwhile the Benkelman beams value of the new roadbed is controlled less than that of the former roadbed, and the benkelman beams value of the top surface of the seeded strip is controlled less than that of the former road surface;2) there forms a simple support top, made of the mixture of lime and pulverized coal and crushed stones, on the steps cut from both sides of U-groove which lies 20cm beneath the surface of seeded strip;meanwhile a piece of typical highway steeled geotextile is used to reduce the stress functioning on the top part of former seeded strip;3) a piece of asphalted geotextile covers the longitudinal joint caused by half-pavement construction to effectively reduce the backscattering cracks and to avoid the destruction caused by the rain water;4) SMA-13 structured asphalt concrete is adopted when the top layer is constructed, for SMA has good property against tracking and slippiness, so as to keep the pavement durable and its structural intensity stronger;and the modulus of resilience is greatly improved by adding the fabric in asphaltconcrete which has a property against tensile-shear.Additionally this thesis puts forward some key steps of construction process and some measures of guaranteeing the construction quality. During the process of constructing macadam pavement with the mixture of lime and pulverized coal, 1) the accuracy of aggregate proportion has been guaranteed by heightening 1 meter the bunker baffle of stabilized soil-mixing machine to avoid material being polluted each other;2) the quality of mixed material has been guaranteed by stalling a vibrating screen with proper mesh size at each laying-off exit of the bunker to avoid the oversize aggregate and lime clusters entering the mixing cabinet;3) the friable state of pavement surface has been avoided by positing professional staff to deal with those rubble aggregate on the edge of paving surface before compaction, to get rid of those aggregate clusters and change the even mixing materials after roller compaction once, and to water the paving surface during the process of compaction;4) the pavement planeness has been guaranteed by using paver with stronger jolt ramming power during the process of paving as well as positing professional staff to keep the planeness through levelling and compacting.The northern part of 205 State Highway within Binzhou city has been in good condition, without any longitudinal cracks on the top pavement above the former seeded strip and on the longitudinal joint parts, since it was reconstructed one year ago, although there are just a few lateral cracks inavoidably caused by the shrinked foundation course. The successful reconstruction of the northern part of 205 State Highway within Binzhou city has practical and immediate significance in both guaranteeing its good quality and cutting its cost. |
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