Articles

Development of Ultra-High-Performance Concrete (UHPC) for Bridge Deck Overlay

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Abstract

With superior mechanical strength and durability, ultra-high-performance concrete (UHPC) is becoming an emerging rehabilitation material for the bridge deck overlay. However, there still exists several challenges to prevent the wide applications of UHPC overlay: (1) the high shrinkage of UHPC leads to high cracking potentials, especially on early ages; (2) the highly flowable UHPC causes difficulties for the sloped casting on the bridge deck; (3) the high mixing difficulty restrains the large-scale production on job sites. To address the aforementioned problems, the Stevens team first optimized UHPC mixtures by properly combining the pre-saturated lightweight sand, expansive agent, and shrinkage-reducing agent, in which the shrinkage was significantly reduced, and mechanical strength was kept at the superior level. Compared to the control mixture, the peak and cumulative cracking potentials of optimized UHPC were reduced by 65% and 60%. Subsequently, the Steven team developed a thixotropic UHPC to facilitate the sloped overlay construction. A new type of well-dispersed nanoclay suspension was utilized to enhance the thixotropy. Results showed the nanoclay addition effectively enhanced the thixotropy of UHPC but slightly reduced the bond strength between the UHPC overlay and substrate. However, after applying the optimal vibration, the bond strength was improved without affecting its shape stability. In the end, the mixing kinetics of UHPC in the mixing process was investigated and a multi-batching method for large-volume production of UHPC was developed.

Keywords: ultra-high-performance concrete, expansive agent, prewet time, cracking potential

How to Cite:

Du, J. & Meng, W., (2023) “Development of Ultra-High-Performance Concrete (UHPC) for Bridge Deck Overlay”, International Interactive Symposium on Ultra-High Performance Concrete 3(1): 49. doi: https://doi.org/10.21838/uhpc.16671

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