Abrasion damage of concrete for hydraulic structures and mitigation measures: A comprehensive review

Abrasion damage of concrete induced by sediment-laden flow has been a significant durability problem for hydraulic structures. Due to the complexity of dynamic fields and concrete properties as well as the interaction effects between them, many aspects are still subjected to debate despite the tremendous efforts that have been made. In light of this and in order to further advance our understanding, this work aims to present a state-of-the-art review on critical aspects of the abrasion behavior of concrete. Important theoretical basics and mechanisms behind abrasion-induced concrete damage are presented first and different performance indicators that have been used for abrasion damage characterization are discussed. Following that, relevant abrasion test methods are comparatively reviewed and the effects of important hydraulic parameters and concrete properties on concrete abrasion behavior are analyzed in depth. Moreover, representative prediction models proposed for the estimation of concrete abrasion damage are discussed. In addition, an overview of recent development strategies for improving concrete abrasion resistance is presented. Based on the critical analysis of the research status, some important research gaps and challenges are highlighted

On the growth of national geoparks in China: distribution, interpretation, and regional comparison

Since the year 2000 China has created 139 National Geoparks; it started under the guidance of the former UNESCO\u27s Division of Earth Science, and has therefore become one of the pioneers in this aspect. Many National Geoparks in China have been described over the past decade, but an understanding of the range of various landform features and their connection with geological and climatic constraints has not previously been published. Based on an increasing awareness of National Geoparks, the aim of this contribution is to provide a comprehensive overview of the National Geoparks of China by reviewing the geological heritage and their intrinsic linkages with geological and climatic controls. A regional comparison of the widespread clastic and karst Geopark landforms indicates that the development of these terrains can only be understood within a synthesis of tectonic constraints, climatic changes and lithological properties, whereas the variety of types, forms, scales and development patterns reflect processes in various climatic settings