Engineering application and stability verification of non-premixed UHPC production technology

Abstract

In this paper, the ''non-premixed mixing technology with conventional equipment'' suitable for industrial large-scale production of Ultra-high-performance concrete (UHPC) is proposed, that is, UHPC is not premixed with powder, the conventional concrete batching plant is finely adjusted, and the ordinary concrete feeding and mixing process is used to produce UHPC. Relying on the UHPC bridge deck of the Wujiang River Special Bridge of the Dejiang-Yuqing Expressway, the coarse aggregate UHPC is produced, totaling more than 1600 m3. The engineering practice shows that the time required from feeding to mixing of UHPC in each batch is 8.5–11.5 mins, the production efficiency of UHPC is high by adopting this technology; The compressive strength and flexural strength data of 54 groups of retained samples under the two curing regimes (standard curing and steam curing) conformed to normal distribution, and the standard deviations of compressive strength were 7.05 and 9.42 MPa for the two curing regimes, and 2.00 and 1.79 MPa of flexural strength. The fluctuation of concrete quality is small, and the strength inspection and evaluation meet the requirements; The relationship between the concrete strength of the two curing regimes was compared and analyzed, and suggestions for quickly predicting the concrete strength were given. The use of this technology makes the UHPC production method detached from the premix preparation, which significantly simplifies the production process of UHPC and increases the transparency of UHPC production technology. This paper provides a new idea for the industrial production of UHPC, in order to further promote the large-scale and engineering application of UHPC.

Keywords

• Ultra high performance concrete
• Non premixed
• Production process
• Strength distribution
• Inspection and evaluation