Experiment on erosion-resistance of highway bridge pile foundation material under salt marshes environment(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年01期
- Page:
- 49-58
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Experiment on erosion-resistance of highway bridge pile foundation material under salt marshes environment
- Author(s):
- YAO Xian-hua; FENG Zhong-ju; WANG Fu-chun; XU Zhan-hui; LIU Ning; YAO Guan-bing
- 1. School of Highway, Chang’an University, Xi’an 710064, Shaanxi, China; 2. School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou 450011, Henan, China; 3. Qinghai Province Highway Research Survey and Design Institute, Xining 630100, Qinghai, China
- Keywords:
- bridge engineering; salt marsh; concrete admixture; erosion-resistance coefficient; microscopic mechanism
- PACS:
- U443.15
- DOI:
- -
- Abstract:
- To solve the durability of concrete materials for bridge pile foundation in salt marshes environment, 13 concrete specimens with different mix proportion designs were adopted, which were embedded in sites with four conditions (field surface, underground water, 0.25 m deep from ground and 1.25 m deep from ground) for 360 d under natural conditions of saline corrosion environment of highway bridge pile foundation, and the influences of various factors, including the admixture type (fly ash, slag, silica fume, expansion agent, cementitious calillary crystalline waterproofing material) rust-inhibitor, sulfate-resistant cement and steel liners on the mechanical properties of concrete erosion-resistance of highway bridge pile foundation were studied. The cube compressive strength and concrete quality were test respectively, and the corrosion mechanism of concrete was revealed by conducting microscopic analysis through scanning electron microscope(SEM), energy dispersive spectrometer(EDS) and X-ray diffraction(XRD). In addition, a regression formula of erosion resistance coefficient of concrete with age was put forward. The results show that embedment condition influences the performance of the erosion-resistance of concrete in some degree. For four embedment conditions, specimens of concrete placed on the surface are most seriously corroded. Otherwise, specimens of concrete buried 1.25 m deep in the soil have the least corrosion, but there is a slight difference between different concrete specimens. The mineral admixtures choosing the right mixing (slag with expansive agent(CMP3), fly ash with silica fume (CMP7), cementitious calillary crystalline waterproofing material with silica fume (CMP9)) can effectively improve the erosion-resistance of concrete, and erosion-resistance coefficients of concrete are all above 0.85 under several conditions, which has a good erosion-resistance performance. Reinforcing bar rust-inhibitors have negative effects on the erosion-resistance of concrete. The regression formula of erosion resistance coefficient of concrete with age provides a reference for the prediction of concrete durability. The corrosion products of ettringite, calcite, Friedel salt and thaumasite are found, and the combination of these products will accelerate the corrosion of concrete. Moreover, when the active ingredient Al2O3 in fly ash is high, it will accelerate the formation of ettringite, which is adversely to concrete.
Last Update: 2018-02-06