Resonant Crushing Technology Background for Concrete Road Reconstruction

Current methods for the renovation of old cement concrete road surfaces are generally divided into two categories: non-crushing and crushing.

The main methods for handling broken cement board panels include underlay grouting, surface jointing, or replacing the old panels with new surfaces. However, these methods all have certain drawbacks: they may not be durable, fail to completely resolve the issue of reflective cracks, have long construction periods and high costs, and also lead to a large amount of waste and secondary transportation of road materials, causing damage to the surrounding environment.

The crushed plate type involves breaking cement slabs and using them as the subgrade or base layer for new asphalt pavements, effectively eliminating reflective cracks. It offers numerous benefits in terms of environmental protection, road durability, and driving comfort. Therefore, the technology of crushing old cement concrete pavements is a promising method for the current renovation of such road surfaces.

The Resonant Crushing Technology involves continuously generating high-frequency, low-amplitude vibration energy, which is then transferred to the concrete slab through glass crushing hammers, causing resonance and achieving the crushing effect. The cracks produced by resonant crushing are at approximately a 30°-45° angle to the road surface, with the bottom fragments slightly larger and interlocked, which有利于 maintaining good load-bearing capacity after crushing. The surface fragments are slightly smaller and exhibit a mechanical pattern more akin to graded crushed stone. Domestic research indicates that "the mechanical properties of the resonant crushed layer are more similar to flexible subgrades, with a deformation resistance up to 1.5-3 times that of high-quality dense graded crushed stone." Therefore, the overall crushed layer remains a flexible subgrade with considerable structural load-bearing capacity.

Currently, the semi-rigid subgrade used in our country has inherent, insurmountable defects: thermal shrinkage, drying shrinkage, and cracking, which easily lead to reflective cracks from bottom to top, causing structural damage to the road surface and necessitating "open-heart surgery" style major repairs when the road requires maintenance. In contrast, flexible subgrade differs, with its main mode of damage being functional fatigue on the asphalt surface layer, which can be remedied through preventive maintenance of the surface layer, such as regular resurfacing or milling and overlay, to maintain the original road's good performance. In the renovation of old cement road surfaces, the contribution of the resonant crushing technology lies in eliminating reflective cracks while optimizing the new road structure, making the intermediate structure more stable and compatible, resulting in a flexible subgrade road with good overall integrity and continuous deformation, ultimately achieving high quality, long service life, and ease of maintenance.

The Resonant Crushing Technology is achieved through the RB-500 Resonant Crusher developed by the United States-based Resonant Technology Company. This technology was introduced at the end of the 1980s and has accounted for approximately 75% of the U.S. cement road rehabilitation projects. Concurrently, resonant operations have been expanded to Canada, Mexico, and other countries. The equipment was introduced to China in 2004, with extensive resonant crushing experiments conducted in Shanghai, Zhejiang, Jiangsu, Sichuan, and other regions.

Relying on the resonant technology from the United States, we have successfully developed the high-frequency resonant crusher RPB-GP60 with independent intellectual property rights, tailored to the current state of domestic cement road surfaces. This equipment boasts numerous advantages over American-made counterparts, including high frequency, uniform crushing effects, low failure rates, and no leftover edges on the working surface. Extensive engineering practices across various provinces and regions have proven that this equipment offers more advanced functionality and superior resonance effects, making it highly suitable for China's complex road conditions. Currently, it can achieve full-depth crushing of old cement slabs, with crushing particle sizes fully compliant with national technical standards.