Name: EDSON ANDRADE DE SOUZA
Publication date: 18/03/2025
Examining board:
Name |
Role |
|---|---|
| ARNALDO GOMES LEAL JUNIOR | Presidente |
| CAMILO ARTURO RODRIGUEZ DIAZ | Examinador Interno |
| CARLOS ALBERTO FERREIRA MARQUES | Examinador Externo |
| MARIA JOSE PONTES | Coorientador |
Summary: Smart concrete is a structural element that can combine both sensing and structural capabilities. In addition, smart concrete can monitor the curing of concrete, positively impacting the design and construction approaches. In the concrete, if the cure is not well developed, the structural element may present generated cracks in this early stage due to shrinkage, decreasing the structural mechanical strength. In this paper, a system of measurement using fiber Bragg gratings (FBG) sensors for monitoring of the curing concrete was developed to evaluate the autogenous shrinkage strain, temperature, and relative humidity (RH) in a single system. Furthermore, K-type thermocouples were used as reference temperature sensor. The results presented a maximum autogenous shrinkage strain of 213.64 , 125.44 , 173.33 to FBG4, FBG5, and FBG6, respectively. Regarding humidity, the measured maximum relative humidity was 98.20 %RH, which was reached before 10 hours. In this case, the recorded maximum temperature was 63.65 °C and 61.85°C by the FBG2 and thermocouple, respectively. Posteriorly, the concrete specimen with the FBG strain sensor embedded was underwent a bend test simulating the beam behavior. The measurement system can transform a simple structure like a beam into a smart concrete structure, in which the FBG sensors’ signal was maintained by the entire applied load cycles and compared with FBG strain sensors superficially positioned. In this test, the maximum strain measurements were 85.65 , 123.71 , and 56.38 on FBG7, FBG8, and FBG3, respectively, in which FBG3 also monitored the autogenous shrinkage strain. Therefore, the results confirm that the proposed system of measurement can monitor the cited parameters throughout the entire process of curing concrete. Furthermore, we compared FBG and electronic strain gauge (ESG)
sensors in strain measurement applied to a concrete specimen in a compression test. The results show that FBG sensors can be applied superficially to several concrete structural elements, and compared with ESG sensors, the optical sensor can provide accurate measurements and information with more detail when submitted to environments with high electrical noise.
