Title:
Sustainable CSA Cement-Based Precast Concrete Tunnel Lining Reinforced with GFRP Bars: Challenges and Opportunities
Author(s):
Simone Spagnuolo
Publication:
Web Session
Volume:
ws_S23_SimoneSpagnuolo.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/2/2023
Abstract:
In underground construction field, one of main methods for the excavation of tunnels is represented by the mechanized excavation method. Tunnel lining is built by means of precast segments, placed by TBM and used as support elements for its advancing phases. During the construction phases, one of the main aspects has to be considered, concerns the logistics of the segments: segments must be at the right place at the right time. To this ends, specific demands are posed on their storage and transportation. The use of low CO2 emission concrete based on calcium sulfoaluminate (CSA) binders allows the production of the elements to be speeded up, a reduction in the number of segments stacked waiting for the required strengths to be achieved and provides a more eco-sustainable process, avoiding the use of steam curing. Due to lower pH generated by CSA cement compared to common Portland one, the steel reinforcement was replaced by low CO2 emission Glass Fiber Reinforced Polymer (GFRP) cage able to resist low-pH values. Based on the experimental and analytical results, the proposed solution, in the next future, could bring sustainable improvements in this field. In fact, the possibility to establish an in-situ pultrusion process of the GFRP bars, the fast curing of the CSA cement-based concrete and the reduction of stacking space could allow for on work-site full prefabrication. This perspective will enable improving the health and socio-economic aspects tied to the reduction of pollution and traffic congestion of the urban areas.