Effect of temperature on the in-situ and post-heating residual strength of FRC tunnel segments by means of Simplified Barcelona test

• Grant number: 15/25457-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2016
• End date: August 31, 2018
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Antonio Domingues de Figueiredo
• Grantee: Dimas Alan Strauss Rambo
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The occurrence of a fire into a tunnel lining can lead to tremendous losses and casualties. In the case of tunnels produced with reinforced concrete segments, even a short exposure time at moderate temperatures can lead to a severe degradation of the cementitious matrix and, in some cases, of the reinforcement. The occurrence of spalling is still more critical, given that it can evolve to a total collapse of the structure. The use of synthetic macrofibers helps to avoid cracking and spalling in tunnel segments. However, when subjected to elevated temperatures, causes losses in reinforcement capacity of segments. In this context, this project aims to investigate the effect of elevated temperatures on the mechanical behavior of FRC (fiber reinforced concretes) tunnel segments by means of Simplified Barcelona Tests. Samples extracted from the tunnel concrete segments will be tested after an exposure period of 1h at constant temperature in two different testing conditions: In-situ (hot condition) and residual (after cooling). Targeted constant temperatures considered will be in a range of 25°C to 600°C, in view of the main dehydration processes present in the Portland cement matrix. Thermogravimetry (TG) and X-ray diffraction (XRD) analysis will be used to study matrix phase changes as a function of temperature. Scanning electron microscopy (SEM) will be addressed in order to investigate the damage processes in the plain matrix and in the fiber-matrix interfaces. The results will be used through AES model to evaluate the possible reduction of the strength capacity of the tunnel segments. Such results will also provide important parameters for future designs of FRC tunnel segments in terms of structural safety, damage tolerance and maintenance.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SERAFINI, RAMOEL; DANTAS, SERGIO R. A.; SALVADOR, RENAN P.; AGRA, RONNEY R.; RAMBO, DIMAS A. S.; BERTO, ANTONIO F.; DE FIGUEIREDO, ANTONIO D.. Influence of fire on temperature gradient and physical-mechanical properties of macro-synthetic fiber reinforced concrete for tunnel linings. CONSTRUCTION AND BUILDING MATERIALS, v. 214, p. 254-268, JUL 30 2019. (17/00125-9, 15/25457-9)

CRUZ BORGES, LEONARDO AUGUSTO; MONTE, RENATA; STRAUSS RAMBO, DIMAS ALAN; DE FIGUEIREDO, ANTONIO DOMINGUES. Evaluation of post-cracking behavior of fiber reinforced concrete using indirect tension test. CONSTRUCTION AND BUILDING MATERIALS, v. 204, p. 510-519, APR 20 2019. (12/24281-6, 15/25457-9)

STRAUSS RAMBO, DIMAS ALAN; BLANCO, ANA; DE FIGUEIREDO, ANTONIO DOMINGUES; FERNANDES DOS SANTOS, EDSON RODRIGO; TOLEDO FILHO, ROMILDO DIAS; MARTINS GOMES, OTAVIO DA FONSECA. Study of temperature effect on macro-synthetic fiber reinforced concretes by means of Barcelona tests: An approach focused on tunnels assessment. CONSTRUCTION AND BUILDING MATERIALS, v. 158, p. 443-453, JAN 15 2018. (15/25457-9)