Aggregate Crushing – An Effective Technique in the "White to Black" Transformation

As one of the early forms of road construction, concrete pavement has faced issues such as cracking, misalignment, bottom voids, and broken slabs due to the increase in heavy vehicles, traffic volume, and extended usage time. Moreover, repairing concrete pavements is more challenging and time-consuming than asphalt pavements, with uncertain results. At the end of the service life for concrete pavements, when other maintenance measures no longer ensure the road's performance,破碎改造 (破碎改造) is one effective approach.

There are two methods for the disposal of broken materials: one is to remove them from the original site, and the other is to utilize them in place. Utilizing the in-situ broken materials allows for the full utilization of old road resources, aligning with China's requirements for a resource-saving and environmentally friendly society. Consequently, this approach has become a trend in the renovation of old cement concrete road surfaces.

Aggregate crushing technology is an effective method for in-situ crushing and reusing old cement concrete pavement. The crushing of concrete pavement requires a balance between structural reduction and increased risk of reflective cracking. While ensuring the structural integrity of the original concrete slabs, the effective modulus after crushing should minimize the likelihood of reflective cracking. The effective modulus of the crushed aggregate is closely related to the particle size after crushing, and there exists a reasonable particle size range that allows the effective modulus to reach an appropriate level. Aggregate crushing technology perfectly meets this requirement.

Pavement fracturing technology should only be applied when conventional maintenance methods fail and it is absolutely necessary to resurface and reconstruct. The loss of strength in the fractured sections is irreversible and serves as a means of reconstruction, necessitating the addition of a new structural layer for the pavement.

Fragmentation technology relies on specialized equipment, primarily two types: one is a multi-impact crusher, which breaks the blocks by the lifting and falling of multiple heavy hammers; the other is a resonance crusher, which breaks old concrete blocks through high-frequency low-amplitude vibrations generated by the vibration beam of the equipment.

Resonant Crusher

Since 2002, Shandong Province has been the first in China to introduce multi-impact crusher stone crushing equipment. The Provincial Department of Transportation Highway Bureau, Southeast University, and Shandong Provincial Highway Construction (Group) Co., Ltd. jointly researched the related technology. In 2005, the technology passed the expert evaluation, and in 2008, it won the First Prize of Shandong Province Science and Technology Progress. By the end of 2008, the technology had been applied domestically over 900 kilometers, and it was basically mature.

Of course, in addition to the crushing and screening technology, there are various other techniques for breaking up old pavement slabs. Due to the varying破碎 effects, the paving structure and the expected service life differ, necessitating a comprehensive technical and economic comparison to select the optimal technology solution for the renovation of old cement concrete roadways.