I. Product Overview

After years of independent research and development, Huainan Xindongchen Holding Group Co., Ltd. invested RMB 150 million in 2022 to build an intelligent production line for coal-based sintered lightweight high-strength fine aggregate, with an annual output of 2 × 200,000 m³. The line is capable of producing a wide range of products with particle sizes from 0.15 mm to 16 mm, bulk density grades from 600 to 1200 kg/m³, and cylinder compressive strength ranging from 5 MPa to over 25 MPa.

Coal-based sintered lightweight high-strength fine aggregate is made from coal gangue through batching, grinding, homogenization, pelletizing, and high-temperature calcination at around 1200°C in a rotary kiln. The product features stable and uniform quality and has a dense honeycomb-like microporous internal structure. It offers the advantages of light weight, high strength, sound insulation, thermal insulation, seismic resistance, impermeability, resistance to acid and alkali corrosion, and fire resistance. This product is the first of its kind in China and was certified in 2024 as one of the first batches of new materials in Anhui Province.

II. Product Advantages

• Technological innovation: Through technological innovation, the company has, for the first time in China, achieved a process breakthrough from building aggregate design, including strength and bulk density, to aggregate manufacturing, including precise proportioning and homogenization, resulting in excellent product quality.

• Green and environmental advantages: Coal gangue lightweight aggregate meets the national requirements for the development of a circular economy and green building.

• Functional advantages: This material features light weight, high strength, thermal insulation, sound insulation, seismic resistance, impermeability, and Class A fire resistance, meeting the development needs of green and energy-efficient buildings.

• Internal curing advantage: Owing to its microporous structure, the material has a water absorption rate of about 10%. After pre-wetting and mixing, it can continuously release water during the hydration process, significantly reducing concrete shrinkage cracking.

• Customized production advantage: The product is manufactured through an industrialized process, and its strength, bulk density, size, and gradation can all be customized according to customer requirements.

III. Lightweight Concrete

Application direction: Promoting the lightweighting of concrete

Application positioning: Ordinary functional lightweight concrete (LC30 to LC50), high-performance lightweight concrete (LC60 to LC100), and lightweight ultra-high-performance concrete (LUHPC > 100 MPa).

Compared with conventional concrete of similar strength, lightweight concrete made with coal gangue lightweight aggregate can reduce weight by approximately 20% to 30%. This helps reduce the dead load of buildings and the burden on urban foundations, lowers the consumption of steel reinforcement and foundation materials, enables concrete lightweighting, and improves the overall performance and economic benefits of buildings. In addition, it integrates thermal insulation, sound insulation, fire resistance, and structural performance into one material system, offering excellent building energy efficiency. Its thermal insulation performance is five times better than that of traditional concrete, and its impermeability is outstanding, reaching Grade P10.

 IV. Application Cases

1. Application in the Shuangliu Bridge: A pioneering high-end application in a national key project

The Wuhan Shuangliu Yangtze River Bridge has a total length of approximately 35 km, a width of 50.5 m, and dual eight-lane carriageways. The entire line is built to expressway standards, with a design speed of 120 km/h.

It features four major characteristics: large span, wide bridge deck, tall main towers, and new materials.

For the first time in a major domestic bridge project, lightweight ultra-high-performance concrete prefabricated components have been adopted. Designed by Hubei Communications Planning and Design Institute and Wuhan University of Technology, the Shuangliu Yangtze River Bridge uses a composite structure of lightweight ultra-high-performance concrete (LUHPC) prefabricated bridge deck panels. The design strength is 120 MPa, and the concrete density is 2150 kg/m³.

2. Ramp bridge at the Zhongshangang section interchange of the Nansha-Zhongshan Expressway

The design strength is 100 MPa, and the density is 2150 kg/m³.