Characterization Of Wet Mix Shotcrete For Small Line Pumping

Author : Xiongxin Wang
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Download or read book Understanding the Placement Mechanism of Wet-Mix Shotcrete and the Influence of Material Properties written by Xiongxin Wang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shotcrete refers to the construction technique that concrete or mortar is conveyed through a hose and pneumatically projected onto substrate surfaces. Shotcrete is broadly used in civil engineering for rehabilitation of existing structures as well as new construction. However, shotcrete construction often suffers from inevitable rebound of aggregates and other placement problems, which may lead to low efficiency, material waste, poor construction quality, and work environment hazard. These placement problems are directly associated with the spray behavior of shotcrete, which are governed by the material properties, such the flowability and viscosity of the shotcrete mixture. The current research aims at fundamentally understanding the placement mechanism of wet-shotcrete, and the influence of various materials parameters on the placement and hardened properties of shotcrete by directly characterizing the spray behavior and correlating that to the final material placement. In this study, a series of wet-mix shotcrete experiments is conducted. The full spray behavior of wet-mix shotcrete is characterized using a high-speed camera and image analysis technique. The placement and rebound, and qualitative hardened properties of shotcrete are also experimentally determined. A correlation between the spray behavior and the placement and hardened properties of the shotcrete is then established. For the mortar droplet with larger size and higher velocity, it tends to be more easily deposited on the receiving surface, causes a higher placement and build-up thickness, less rebound and better compaction. With the material flowability increases, smaller droplets with lower velocities are generated during the spray process, correspondingly results in less in-place materials and higher rebound with lower build-up thickness and larger porosity. Similarly, while the material viscosity increases, larger droplets are produced, which leads to higher placement, less rebound and larger build-up thickness with smaller porosity.