Effect of a Novel Vibration Mixing on the Fiber Distribution and Mechanical Properties of Ultra-High Performance Concrete

Abstract

A novel double-axis vibration mixing technology is presented to further enhance the performance of ultra-high performance concrete (UHPC). It improves the problem of inefficient zone in concrete mixing and enhances the homogeneity of concrete through the coupling of vibration and velocity fields during mixing. The X-CT scan results demonstrate that this novel technology improves the fiber distribution coefficient from 0.512 to 0.581. Moreover, the standard deviation of fiber orientation is reduced, the proportion of invalid fibers is decreased, and the pore space distribution is more uniform. The mechanical experimental results show that the new vibration mixing technology improves the mechanical properties of UHPC, and the percentage of early strength improvement is more significant; the impact compressive strength and the toughness of UHPC are also strengthened. The vibration mixing technology is expected to achieve the reduction of raw materials dosage with the same mechanical properties to reduce the cost and carbon emission.

An overview of progressive advancement in ultra-high performance concrete with steel fibers

“…The standard concrete mixer is used for mixing UHPC. Figure 8 shows the steps of UHPC mixing, as presented by Zheng et al (2022), similar to conventional concrete. The superplasticizer and water are added after mixing powdered ingredients for almost 10 min, and the mixing process is repeated for another 5-10 min.…”