Due to the complex terrain, changeable climate and large temperature difference between day and night in northern Guizhou, coupled with the lack of natural sand resources, there are some problems in the preparation of high-performance concrete with machine-made sand, such as segregation, bleeding and poor workability. Therefore, it is more difficult to control the quality of concrete engineering, and the durability requirements of high-speed highway concrete are higher.

The project relied on Zhengxi expressway, South Ring Expressway and Xiuyin expressway. The research group has carried out the following research.

lStudy on preparation technology of machine-made sand high performance concrete based on cementitious system and aggregate system.

lStudy on the determinants and development law of early strength, early crack, fair-faced effect and elastic modulus of manufactured sand concrete

lStudy on complete construction technology of precast T-beam under regional environmental characteristics

lStudy on super high pumping technology of concrete for high pier and column in valley.

The main innovations of the project are as follows.

lPreparation technology of high performance secondary lining concrete with machine-made sand. The research results of the project have effectively solved the problems of difficult construction and quality assurance of concrete for secondary structure, difficult development of fair-faced effect of precast T-beam under the restriction of raw materials, difficult pumping of high pier columns above 150m in the valley and high crack risk.

lPreparation and construction technologies of T-shaped precast high-performance concrete beam by machine-made sand, which improved production efficiency and product quality, ensure the quality stability of finished products, and reduce later repair, which will produce obvious economic benefits.

lComplete set of ultra-high pumping and crack prevention technology for concrete of 150m high column with machine-made sands, which has obvious economic benefits in improving pumping efficiency and ensuring product quality.

Effect of secondary lining concrete of tunnel

T-shaped precast concrete beam

Crack resistant concrete for high pier column

Zhengxi expressway

South Ring Expressway

Xiuyin expressway