Recently, the "Construction Technology for Dry Preparation of Manufactured Sand via Intermixing with Dual-Host Crushing"—jointly developed by Jiangxi Provincial Communications Engineering Group and Fujian Ninon Technology Co., Ltd.—officially passed the scientific and technological achievement evaluation by the China Highway Construction Industry Association. Experts agreed the results are domestically leading, with notable economic/social benefits and broad promotion value. This technology’s core lies in optimizing sand making machine configurations, especially adopting dual VSI crushers (vertical shaft impact crushers) to solve traditional sand making pain points.
On July 22, 2023, the evaluation meeting was held in Hefei. After listening to reports, reviewing materials, and discussing, experts confirmed: 1) Materials are complete and data reliable; 2) The team achieved major innovations via tests and verification—proposing a dual-host sand making process (using two VSI crushers as core sand making machines) with adjustable speeds to flexibly adjust manufactured sand’s fineness modulus, and developing a swing lever device for automatic control of manufactured sand’s powder content.
1. The materials provided by the research team are basically complete and the data are reliable, which meet the requirements for scientific and technological achievement evaluation.
2. The research team conducted a systematic study on the "Construction Technology for Dry Preparation of Manufactured Sand via Intermixing with Dual-Host Crushing" through means such as laboratory tests and engineering verification, and achieved the following major innovative results: A dual-host sand-making process with adjustable rotating speed was proposed, realizing the reasonable adjustment of the fineness modulus of manufactured sand. A swing lever device with multiple exhaust pipes equipped with powder suction heads and discharge ports arranged above the vibrating screen was developed, enabling the automatic control of the powder content in manufactured sand.
Technical Principles and Performance Indicators
This construction method applies to dry preparation of manufactured sand for all construction-use manufactured sand concrete. Its core is a dual-host sand making machine system: a coarse and a fine crushing host, both VSI crushers. The two VSI crushers run at different speeds (10-20% difference by parent rock lithology), achieving different linear velocities and particle kinetic energies for varied crushing ratios. This solves the issue that coarse sand making machines (single VSI crusher) can’t break 0-4.75mm fine particles. Adjusting the two VSI crushers’ feed proportion and particle size lets the sand making machine system intermix manufactured sand of different gradations and fineness moduli to meet diverse needs.
Comparison with Similar Domestic and International Achievements
The project—focused on optimizing sand making machine and VSI crusher tech—has secured 2 invention patents (e.g., for dual VSI crusher control), 2 utility model patents (e.g., sand making machine adjustment structures), 1 design patent, 1 provincial construction method, 1 local standard, 1 transport commission research project, and 5 papers. It also won awards like the China Highway Society’s Micro-Innovation Silver Award. Compared with domestic and foreign similar tech, its sand making machine and VSI crusher-integrated solution ranks leading.
Economic and Social Benefits
(1) The dual-host (dual VSI crusher) sand making machine system’s "dry preparation process" boosts manufactured sand production rate by 15%-25%. For the same output, per-ton energy consumption drops 1.6kw (saving 1-2 yuan/ton), cutting sand making machine maintenance costs—saving over 2 million yuan alone in the Yisui Expressway project.
Prospects for Promotion and Application
By adopting the dual-host (dual VSI crusher) intermixing process for dry manufactured sand preparation—centered on an optimized sand making machine system—extensive production tests have been done on various sand and gravel raw materials. This sand making machine (with dual VSI crushers) has also been applied in engineering practices with good results, improving manufactured sand’s gradation and fineness modulus stability. Thus, this VSI crusher-integrated sand making machine tech has broad promotion value in China.