The Mechanical Properties Analysis For Cement Conerete Pavement Based On MHB Rubblization Technology

Cement concrete pavement have been widely used in road construction of our country. With the social economical gallop of our country, traffic stream and axle load were increased, masses cement concrete pavement began to have some structural destruction as cracks, broken and dislocation to some extent which severely influenced the normal character of service, therefore the reconstruction is unavoidable.Rubblization is an important way to deal with old PCC slab and has a development history of more than thirty yesrs in the United States. MHB (Multiple-Head Breaker) as a kind of broken equipment comes into our country in 2002; In the domestic such as shandong and zhejiang province also in the early reconstruction of cement concrete pavement in the application of this technology. Practice, shows that using this technology to eliminate the reflection crack of asphalt overlay is effective. This technology is still in the initial stage of study in China and there are also many problems on process characteristics, working mechanism and the quality control of construction.In this paper, the MHB rubblization decision, formation mechanism of the intensity, the quality control of construction and the physical design of asphalt overlay are futher studyed by ways of combining theory research and finite element analysis methods.The first is evaluate the performance of old PCC slab and application decision of MHB rubblization technology. Based on foreign engineering experiences and results of research, factors contribute to properties evaluation of old pavement including PCI, DBL and soil condition, the most important factor is soil condition. The contrast analysis on the economy of MHB rubblization technology shows that economic critical point is main factor to chose reconstruction program.Then modal transient response method is used to imitate process of rubblization and analisis of stress, and get key parameters for quality control. The crustal stress analysis indicated that the middle of two hammers,the center of hammer and the edge of hammer has the different regularities of the stress distribution in vertical direction.The driving direction almost has no displacement and transverse direction has little displacement, the vertical direction of pavement has maximum displacement.Next, the mechanics characteristic of paved concrete overlay after rubblization is analysed. The paper compares the stress of asphalt overlay on old slab directly and rubblized slab,which shows that stress on rubblized slab is less than on old slab. By increasing the modulus of under layer which shows that the principal stress change little. By changing the height proportion of two main parts of rubblized slab, the result shows that the proportion should be controled between 1:1 and1.4:1, this proportion will keep the intensity of slab and avoid reflective crack as well.At last the paper conclude the construction process for MHB rubblization technology and recommend the physical structure of asphalt overlay.