1. Resonance crushing process
The resonance crusher provides high-frequency and low amplitude excitation and blow to the old cement pavement, so that the cement pavement slab can bear the high-frequency and low amplitude blow force in the vibration and realize crushing.
Since the vibration frequency of the vibration crusher is regulated in the resonance zone of the cement pavement slab system, and the exciting force (striking force) is transmitted downward from the surface layer of the cement slab, an energy gradient is formed in which the hammerhead striking energy expands and transmits downward along the action point, resulting in the fragmentation of the surface layer of the cement slab to form smaller particles and larger particles in the middle layer, The lower layer forms large interlocking cracks, which is more obvious with the thicker the cement panel.
Characteristics of resonance crushing construction process:
1.1 particle size: the gravel layer is from top to bottom, from small to large. The particle size of the surface layer is generally less than 5cm, that of the middle layer is generally less than 8cm, and that of the lower layer is generally less than 20cm. When the cement board layer is thin, it generally shows that the surface layer is less than 5cm and the lower layer is less than 15cm; When the cement panel is thick, the surface layer is less than 5cm, the middle layer is less than 8cm and the lower layer is less than 18cm;
When the cement slab is very thick, it generally shows that the particle size of the surface layer is less than 5cm, the particle size of the middle layer is less than 8cm, and the lower layer is less than 20cm. The above tendency is obvious with the increase of the thickness of the cement pavement slab. The thicker the pavement is, the harder it is, the less obvious the middle layer is, and the larger the particle size of the bottom layer is.
1.2 particle state: the surface particles are loose, the middle particles are inlaid and extruded with each other, and the large blocks in the lower layer are inlaid with each other at an angle of about 30o ~ 60o.
1.3 because the cement panel is broken under high-frequency, low amplitude and high-speed impact in the vibration state, it does not completely rely on the reaction of the lower base course, so it has little impact on the base course of the panel.
Because of the above characteristics of resonance crushing, the construction transformation of "white to black" or "white to white" of the old cement pavement as the base course can eliminate the reflection cracks to the greatest extent, retain the bearing resilience modulus of the original pavement structure and reduce the vibration impact on the original base course.
Because of the high frequency and low amplitude operation characteristics of the resonance crusher, it realizes less and no disturbance to the original pavement base, the pipe network structures under the base and the surrounding buildings.
For the larger particles on the surface after crushing, the vibration compaction and secondary surface crushing can be carried out by z-wheel vibratory roller to realize the compaction of surface fragments and homogenization of particle size.
2. Resonance crushing process flow
Traffic control → pretreatment of pavement defects and construction of pavement drainage facilities → marking of pipe network under the pavement and construction boundary of bridge cover → making resonance crushing construction test section to determine construction parameters → construction of resonance crushing of cement pavement and removal of foreign matters on the original pavement after crushing → secondary crushing and compaction by z-wheel vibratory roller → spraying prime coat oil or spraying emulsified asphalt → Pave asphalt mixture surface layer in layers (white to black) or pave new cement concrete pavement (white to white) → construction cleaning and subsequent maintenance.