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DEGRADATION AND ECOLOGICAL RESTORATION OF ESTUARINE WETLANDS IN CHINA

Study on Durability against Dry-Wet Cycles and Chloride Ion Erosion of Concrete Revetment Materials at the Water-Level-Fluctuations Zone in Yellow River Delta Wetlands Rui Sun 1 & Dongmin Wang 1,2

&

Yiren Wang 3 & Lei Zhang 1 & Yue Gu 1

Received: 17 February 2020 / Accepted: 5 June 2020 # Society of Wetland Scientists 2020

Abstract This study was aimed at exploring the durability of concrete revetment materials at the water-level-fluctuations zone of the Yellow River Delta Wetlands. The simultaneous effect of mineral admixtures (i.e., fly ash, slag, and silica fume) and polypropylene fiber on the resistance of concrete revetment materials to chloride erosion, was presented. Under the artificial simulation environment of dry-wet cycles and chloride ion (Cl−) erosion coupling, the evolutions of macro-mechanical properties and the microscopic composition of mineral admixtures-fiber-blend concrete was investigated via compressive strength tests and X-Ray Diffraction (XRD), Mercury Intrusion Porosimetry (MIP) test, for durations of 120 days. The results showed that, under the longterm dry-wet cycles and chloride ion coupling erosion, fly ash and slag provide additional Al2O3 to react with Cl−, and tend to produce Friedel’s salt with smaller interlayer spacing, thereby realizing concrete possessing higher chemical binding capacity with Cl−. The improvement in the physical adsorption capacity of concrete with Cl−, which was due to the formation of additional hydration products of calcium-silicate-hydrate (C-S-H) gel. These materials showed exhibited good resistance to dry-wet cycles and Cl− erosion resistance, and thus were deemed to be suitable for the preparations of concrete revetment materials at the waterlevel-fluctuations zone. Keywords Dry-wet cycles . Chloride ions erosions . Water-level-fluctuations zone . Concrete . Mineral admixtures

Introduction To protect levees against the impact of water waves and maintain the stability of the shoreline, hard revetment materials based on marine concrete have been developed and have gradually become widely used. The durability of marine concrete is often threatened by environmental deterioration and climate

* Dongmin Wang [email protected] 1

School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing, Beijing 100083, China

2

Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou University, Binzhou 256603, China

3

School of Civil Engineering, Sun Yat-Sen University, Guangzhou 510275, China

change (Huang and Wu 1983; Wu 2010; Mohammed et al. 2019), and serious economic losses have been incurred in many countries and regions due to the shortening of its service life (Angst et al. 2009; Stewart et al. 2011; Lin et al. 2014). The total cost of damages due to corrosion in China in 2014 was 2127.82 billion yuan, which accounted for 3.34% of China’s gross domestic product in 2014, implying that each Chinese citize