PSI - Issue 28

N.A. Kosheleva et al. / Procedia Structural Integrity 28 (2020) 1883–1891 Author name / Structural Integrity Procedia 00 (2019) 000–000

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depends on the shape of the sample. The maximum shrinkage of the samples occurred in the period before the initial setting time of the cement, which limits the use of the embedded fiber-optic sensors for recording this process. Figure 9 shows strain graphs for a cylindrical cement sample (sample 1), a prismatic cement sample (sample 2), as well as for a cylindrical concrete sample (sample *(Kosheleva, Serovaev and Gusev, 2020)). The presented strain values were averaged for each sample over all embedded FBGs.

Fig. 8. Samples shrinkage during first 72 hours.

Fig. 9. Mean strain value plot for different samples.

Placing several fiber-optic point sensors along the length of the samples provides information on the strain distribution pattern. The dependence of strain on the length of the sample is shown in Fig. 10. The data are given for the moments of time when the mean value for all sensors of each sample reaches its maximum (sample 1 - 13 hours after casting, sample 2 - 14 hours after casting)

Fig. 10. Strain distribution along the length of the samples.