Flexural Fatigue Behavior of Prestressed High-Performance Concrete Bridges with Double Mineral Fine Powder Admixture: An Experimental Study
Year: 2024
Type: article
Abstract: High-performance concrete (HPC) is commonly used in the main structures of bridges. HPC is widely applied in the main structures of bridges, yet integrating fly ash and mineral powder as admixtures into prestressed HPC bridges remains some skepticism. To address this, this paper conducts scaled-model experiments to analyze the flexural fatigue behavior of prestressed HPC bridges with double mineral fine powder admixtures (PB-DA). This paper derives the similarity criteria for a simply-supported beam bridge under concentrated load based on similarity theory. Subsequently, following these criteria, a 30m long actual bridge is scaled down to a 6m PB-DA at a 1:5 scale. For this scaled PB-DA, the concentrated load is reduced to 1/25 of the actual bridge while the strain remains the same as in the actual bridge. The double mineral fine powder admixture (D-A) was produced and used to fabricate PB-DA by mixing fly ash and mineral powder. Five PB-DAs were constructed, with C50 and C80 concrete strength grades, and admixture ranges from 10% to 32%. Sinusoidal half-wave constant stress amplitude loading at 5Hz frequency was applied, with 2 million fatigue loading cycles. After fatigue loading, a continuously increasing static load was applied until the PB-DA failed. Experimental results show that the upper part of the PB-DA is compressed, and the lower part is in tension. The PB-DA strain distribution from top to bottom generally conforms to the plane section assumption. During 2 million fatigue loading cycles, 200,000 cycles mark the beam strain and stiffness evolution boundary. Below 200,000 cycles, the PB-DA strain rapidly increases, and flexural stiffness quickly decreases. Beyond 200,000 cycles, the rate of increase in strain and the rate of decrease in flexural stiffness significantly slow down. After fatigue loading, the PB-DA displacement increases exponentially under a continuously increasing static load. The crack distribution is uniform across all PB-DA, with the cracks being sparsest at a 30% admixture. A comprehensive analysis of the above results indicates that all the PB-DAs exhibit good flexural fatigue behavior in this paper. Notably, when the content of the D-A reaches 30%, the degree of strain increases, the reduction in flexural stiffness, and the extent of damage in the PB-DA significantly decreases. This paper's conclusions provide a reference for applying D-A at PB-DA.
Source: Applied Sciences
DOI: 10.3390/app14177511
Authors: Zhiguo Zhang, Haoran Li
Institution: Shijiazhuang Tiedao University
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,728
OpenAlex ID: W4401894501