Concrete Road Reconstruction -- Background of Resonant Crushing Technology

Currently, the methods for renovating old concrete road surfaces are generally categorized into two major types: non-crushing and crushing.

The main methods for handling broken cement board panels include sub-base grouting, surface jointing, or replacing the old panels with new layers after removal. However, these methods all have certain drawbacks: poor durability, inability to fully resolve reflective cracking issues, long construction periods, high construction costs, and the wastage and secondary transportation of a large amount of road materials, which can cause damage to the surrounding environment.

The crushed board category involves breaking up concrete slabs to serve as the subgrade or sub-subgrade for new asphalt pavements, effectively eliminating reflective cracking. It offers numerous benefits in terms of environmental friendliness, road durability, and vehicle suitability. Therefore, the technology for crushing old concrete road surfaces is a promising method for the current transformation 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 approximately at a 30°-45° angle to the road surface, with the bottom fragments slightly larger and interlocked, which有利于 maintaining good bearing capacity in the crushed structure. The surface fragments are slightly smaller, and their mechanical pattern is more similar to graded crushed stone. Domestic research indicates that "the mechanical properties of the resonant crushed layer are closer to flexible subgrade, with an anti-deformation capability that is 1.5 to 3 times that of high-quality dense graded crushed stone." Therefore, the overall crushed layer remains a flexible subgrade with considerable structural bearing capacity.

Currently, the semi-rigid subgrade used in our country has inherent, insurmountable drawbacks: thermal shrinkage, drying shrinkage, and brittleness, 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, 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 resonance fracturing technology is to eliminate 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 lifespan, and ease of maintenance.

The Resonance Crushing Technology, achieved through the RB-500 Resonance Crusher developed by the United States-based Resonance Technology Company, was introduced at the end of the 1980s. It has undertaken approximately 75% of the U.S. cement road reconstruction projects. Concurrently, resonance business has been expanded to countries like Canada and Mexico. The equipment was introduced to China in 2004, with extensive resonance crushing experimental projects conducted in Shanghai, Zhejiang, Jiangsu, Sichuan, and other regions.

Relying on the resonant technology from the United States, we have successfully developed the RPB-GP60 high-frequency resonant crusher with independent intellectual property rights, tailored to the current state of domestic cement road surfaces. This equipment boasts several advantages over American-made counterparts, including higher frequencies, uniform crushing effects, lower failure rates, and the ability to leave no edge or corner 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 the complex road conditions in our country. Currently, it can achieve full-depth crushing of old cement slabs, with particle sizes fully compliant with national technical standards.