Dynamic Detection And Squeezing Technology Research On Cavity Beneath Cement Concrete Pavement Slab

Traffic is economics lifeline of society, expedite of highway will make for social development of economy. This needs to carry on security measuring and monitoring to the highway frequently, so as to ensure the normal use of the highway. With the great development of highway construction in the China, we need a advanced ,late-model proof-testing technology impendency. Cavity beneath slabs is the generally disease of the cement concrete pavement. It is the chief reason of the pavement slabs rupture. In the engineering practice, there isn't effective measure to detect the existence and the destruction degree of the slabs up to the present.Testing of slab vibrating image, used in road non-destructive detection, is a new technology developed recent years. Because of its high measure precision, it can meet the demand of measure error, etc. It will widely used in future. After being transient impacted by hammer, the slab will vibrate freely. The natural frequency of vibration relates to the supporting condition, the destruction degree, etc. In order to offering theoretic basis for the detection of cavity beneath slabs in the engineering, finite element software ANSYS is utilized to analysis the mode of slab in this text, the vibration characteristic of the slab in different conditions is discussed. By analyzing the results in practice, the standard is provided finally. If the cavity beneath slab is serious, the natural frequency is relative low-commonly less than 50 Hz . If the subgrade is well and can support the slab well, the natural frequency is more than 200 Hz generally. Squeezing technology is a kind of remedy with trait of utility and efficiency. In order to get a favorable effect, we must to research into every tache on it. The author also did research on a kind of squeezing material which is made up of cement, sand, fly ash> admixture and water. This material which was developed on the basis of large amount of tests has the proprieties of good self-flowing density> high earlier strength , non-segregation ,non-weepage and non-contractility. For different destruction degree, we gained the material by change its directions. In addition, the author did research on squeezing process and reinforce estimate. Finally, combine the instance highway testing, it further proved the method of vibrating image testing and squeezing technology are feasibility and superiority.